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The current study investigates the effect of water spray cooling on the performance of a photovoltaic panel (PV). The advantage of this method compared to other methods is it provides surface cleaning besides the cooling effects which affects the long-term performance of the panel. The performance of a PV panel is correlated to the temperature of the panel and increases by 0.35–0.7% for each degree drop in surface temperature depending on the solar radiation. The goal of this study is to examine the influence of various factors, including the formation and thickness of a water film on the surface of PV cells, the rate of water consumption, and the spray distance on the performance of the PV panel. The evaluation of the PV output power and electrical efficiency indicates that using an arrangement of nozzles with maximum film coverage and minimum overlap between nozzle streams delivers the best cooling performance. Specifically, it is observed that spraying by 5 nozzles with droplet diameters of 113, 49, and 32 μm, causes a mean enhancement in solar panel efficiency by 19.9%, 17.2%, and 15.7%, with a maximum of 22.72%, 18.62%, 16.87%, respectively. These findings underscore substantial opportunities for enhancing the electrical performance of PVs through using spray cooling. [ABSTRACT FROM AUTHOR]

• A numerical simulation was conducted to analyze the susceptibility to crosswinds during the spraying of the air cooler. • The flow field temperature within the skid-mounted CNG air cooler when subjected to crosswind conditions was analyzed. • The installation of baffles enhances the air intake of the cooler, which effectively eliminates the adverse effects of ambient wind. Air cooler is a critical heat dissipation equipment applied in the field of oil and gas storage, which is mainly used to control the temperature during oil and gas storage and ensure the safety of oil and gas storage. After the installation of the spray cooling system on the skid-mounted compressed natural gas (CNG) air cooler Suqiao gas storage, the inlet air temperature of the air cooler decreases, resulting in reduced compressor power consumption. This effectively addresses the issue of unit shutdown due to high temperatures during the summer. However, the actual spray effect on-site reveals the impact of crosswinds, which poses a challenge. In this study, the flow field and causes of the skid-mounted CNG air cooler equipped with a spray cooling system under the influence of crosswinds are analyzed. Additionally, a solution involving the installation of a baffle is proposed. The results highlight that crosswinds have an adverse effect on outdoor spray cooling. With the installation of the baffle, the low-temperature area expands, resulting in lower temperatures. The cooling range is approximately 2 K, effectively counteracting the negative effects of crosswinds. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Iron deficiency is a global nutritional concern, and food fortification is a strategy to address it. However, direct iron fortification can negatively impact sensory attributes. Spray chilling microencapsulation offers a solution while enhancing iron bioavailability. This study aimed to produce iron‐containing microparticles using spray chilling with varying ratios of beeswax and cocoa butter. The ratios had minimal impact on overall yield (73%–75%). The microparticles exhibited β and β′ polymorphic forms, and the inclusion of cocoa butter led to a more amorphous and heterogeneous matrix, resulting in more complex thermal behavior. Higher cocoa butter content improved iron retention (79%–81%) compared with higher beeswax concentrations (69%–70%). LPMs with greater cocoa butter content exhibited reduced iron release, with release kinetics following diffusion and relaxation mechanisms. Iron release across different temperatures ranged from 0.11 to 0.42 mg L−1, influenced by the lipid matrix, particle distribution, and size. The highest release was attributed to smaller, more homogeneous particles containing only one lipid in the matrix. LMPs effectively protected iron release under simulated gastric conditions, allowing significant release in simulated intestinal conditions (36.1%–56.3%). These iron microparticles show potential for use in the food industry, particularly for fortifying various food products, including infant formulas and supplements. [ABSTRACT FROM AUTHOR]

For the problem of high temperature heat damage at 1012102 working face in Yuanzigou Mine, the best spray pressure and nozzle atomization parameters are determined by using the method of spray cooling experiment. The numerical simulation method is used to simulate and analyze the influence of different spray temperature and spray spacing conditions on the cooling effect, and the comfort of human body before and after spray is used to analyze by the linear regression method. The results show that: when the spraying system in the synthesized mining face adopts the group spacing of 10 m, the water temperature is 286 K, and the pressure is 6 MPa, the single group peak temperature reaches 1.3 ℃ compared with the conventional ventilation method. After the application in the field, the temperature of most areas on the sidewalk side of the working face was lower than 26 ℃, the maximum temperature dropped to below 27 ℃, the minimum temperature was as low as 24.7 ℃, which effectively realized the regional cool.

Outdoor atriums have recently been applied with increasing frequency for natural illumination, but they produce a harsh thermal environment easily in summer. Moreover, overheating of the outdoor atrium necessitates air-conditioning to moderate indoor thermal comfort. Simultaneously, the substantial heat emissions from air-conditioning outdoor units worsen the outdoor thermal environment, creating a vicious cycle. Traditional passive evaporative methods involving water and greenery, while capable of regulating the thermal environment, suffer from low evaporative efficiency and pose significant challenges. To improve thermal environment in outdoor atriums, the spray system was employed due to its high cooling efficiency, especially in open or semi-open spaces. In this study, a comparative experiment was conducted to evaluate the effectiveness of using a spray system for evaporative cooling in open outdoor spaces. Furthermore, employing high-efficiency evaporative cooling through spraying to disrupt the vicious cycle of indoor and outdoor thermal environments. The dual goals include regulating indoor and outdoor thermal conditions while also mitigating the local heat island effect. Temperature and humidity distribution within the atrium and adjacent hallways were monitored, along with the impact on air-conditioning operation consumption in neighboring offices. Results showed that the spray system significantly improved the thermal environment in the outdoor atrium, reducing the average and peak air temperatures by 0.94–2.83 °C and 2.92–5.21 °C, respectively. It also resulted in a drop in the average temperature by 0.56–1.62 °C and the peak temperature by 2.31–3.25 °C in adjacent hallways. This effectively eased the issue of overheating in these areas while raising the comfort level in adjacent office spaces. The predicted mean vote decreased from 1.46 to 0.87, indicating a significant improvement in thermal environment in neighboring offices. Furthermore, the daily energy consumption was reduced by 10.6–12.4% in neighboring offices. This study provided the valuable guidance for improving thermal environments within outdoor atrium. [ABSTRACT FROM AUTHOR]

In the continuous casting process, the heat transfer effect of secondary cooling plays an important role in the quality of the slab. The cooling intensity and cooling uniformity of the secondary cooling nozzle need more efficient spray cooling to achieve. Herein, the cold characteristics of different types of nozzles were compared. It is found that the second type of air mist nozzles have more uniform water density and striking force. On this basis, high‐temperature heat transfer experiments for casting billets were carried out to study the heat transfer coefficients of different air mist nozzles in the secondary cooling zone of continuous casting. It is found that the heat transfer coefficient increases as the distance of the temperature measurement point from the nozzle directly below increases. The heat transfer coefficients of the casting billet in both the jet and non‐jet zones are decreasing to varying degrees. When the temperature drops to 600 °C, the second type of air mist nozzle shows a faster temperature drop at the point of measurement, a smaller difference in time taken for temperature drop between jet and non‐jet zones, and faster and more uniform spraying, leading to a more significant trend of increasing heat transfer coefficient. [ABSTRACT FROM AUTHOR]

Probiotics, known for their health benefits as living microorganisms, hold significant importance across various fields, including agriculture, aquaculture, nutraceuticals, and pharmaceuticals. Optimal delivery and storage of probiotic cells are essential to maximize their effectiveness. Biopolymers, derived from living sources, plants, animals, and microbes, offer a natural solution to enhance probiotic capabilities and they possess distinctive qualities such as stability, flexibility, biocompatibility, sustainability, biodegradability, and antibacterial properties, making them ideal for probiotic applications. These characteristics create optimal environments for the swift and precisely targeted delivery of probiotic cells that surpass the effectiveness of unencapsulated probiotic cells. Various encapsulation techniques using diverse biopolymers are employed for this purpose. These techniques are not limited to spray drying, emulsion, extrusion, spray freeze drying, layer by layer, ionic gelation, complex coacervation, vibration technology, electrospinning, phase separation, sol-gel encapsulation, spray cooling, fluidized, air suspension coating, compression coating, co- crystallization coating, cyclodextrin inclusion, rotating disk, and solvent evaporation methods. This review addresses the latest advancements in probiotic encapsulation materials and techniques, bridging gaps in our understanding of biopolymer-based encapsulation systems. Specifically, we address the limitations of current encapsulation methods in maintaining probiotic viability under extreme environmental conditions and the need for more targeted and efficient delivery mechanisms. Focusing on the interactions between biopolymers and probiotics reveals how customized encapsulation approaches can enhance probiotic stability, survival, and functionality. Through detailed comparative analysis of the effectiveness of various encapsulation methods, we identify key strategies for optimizing probiotic deployment in challenging conditions such as high-temperature processing, acidic environments, and gastrointestinal transit. The findings presented in this review highlight the superior performance of novel encapsulation methods using biopolymer blends and advanced technologies like electrospinning and layer-by-layer assembly, which provide enhanced protection and controlled release of probiotics by offering insights into the development of more robust encapsulation systems that ensure the sustained viability and bioavailability of probiotics, thus advancing their application across multiple industries. In conclusion, this paper provides the foundation for future research to refine encapsulation techniques to overcome the challenges of probiotic delivery in clinical and commercial settings. [ABSTRACT FROM AUTHOR]

To reduce the energy consumption of the refrigeration system of the data center and solve the problem of high power consumption of refrigerant pump heat pipe composite air conditioner in summer, the energy efficiency of the unit was improved by installing a spray cooling device on the outside of the condenser, and the performance research and applicability analysis were carried out under different working conditions and in various cities. The results show that the total refrigeration power of fluorine-pump heat pipe composite air conditioner is reduced from 3. 44. 4.51.and 6.48 kW to 2.81,3.66 and 4.89 kW at 15,25,and 35 °C at outdoor temperatures, and the energy efficiency ratio (EER) is increased by 13.4%, 27%, and 30.7%, respectively, compared with the spray cooling device without spray cooling device. Further analysis shows that in the five typical cities of Harbin, Beijing, Kunming, Shanghai, and Guangzhou, the annual energy efficiency ratio (AEER) increased by 4.16%,6.69%.9.88%,10.76%, and 19.65% respectively. The energy efficiency ratio improvement rate of air conditioning increased with outdoor temperature. The energy-saving effect was more significant in cities with a large proportion of medium and high-temperature duration. [ABSTRACT FROM AUTHOR]

Spray cooling is an effective solution for high heat flux dissipation challenges. Accurate prediction of heat transfer efficiency by numerical simulation can reduce the cost of spray cooling in engineering applications. To improve the accuracy of numerical simulation, this study develops a mathematical model for droplet collision and heat transfer response based on experimental data. In spray cooling experiments, droplets are sprayed onto a 200 °C aluminum alloy thermal wall using an atomizing nozzle, temperature is monitored, and the curve of heat flux variation during cooling is estimated from temperature data. Analysis of high-speed photography results provides the droplet diameter, velocity, and spatial distribution. We discover that the average Weber number of droplets, We, has a power-law relationship with the volumetric flow rate, Q, as We ∼ Q1.55. The velocity and position of spray droplets approximately follow a normal distribution, while the diameter follows a Log-normal distribution. By analyzing the relation between heat flux and spray distribution, an experimental-data-based model, named Droplet Collision-Associated Heat Transfer Model, is designed. Integrating this experimental-data-based model with the discrete phase model (DPM), the heat transfer evolution process in spray cooling is simulated with high reliability. Particles sources are generated based on the experimentally obtained droplet parameter probability distributions, DPM is used to capture the trajectories of droplets, and the droplet impact heat transfer correlation model calculates the thermal response of the wall. Compared with experimental results, the simulation error is only 7.49%. Simulation results indicate that spray cooling at high flow rates has better temperature uniformity. [ABSTRACT FROM AUTHOR]

The rapid development of train transportation toward higher speed and heavier load requires superior wheel materials with high strength and toughness. Herein, a 20Mn2SiNiMo bainitic wheel steel is developed and bainitic wheels are produced. The quenching and tempering process of bainitic wheels is studied considering the bainitic ferrite content and stability of retained austenite (RA). The quenching process includes water spraying and air cooling. Proeutectoid ferrite can be suppressed during the water‐spraying process. During air cooling, the bainitic ferrite transformation is promoted and the stability of RA is improved with the extension of cooling time. Corresponding microstructure of as‐quenched steel at wheel rim is bainite with different morphologies, martensite, and RA. The evolution of RA at lower and higher tempering temperatures is dominated by carbon enrichment and carbon consumption, respectively. Yield strength of bainitic wheel steel mainly comes from body‐centered cubic phase (containing martensite and bainitic ferrite). The increase of dislocation density and the decrease of effective grain size are beneficial for yield strength improvement. Bainitic packets with various direction, deformation‐induced martensite transformation of RA, and plastic deformation all play an important role in enhancing the toughness of bainitic wheel steel. [ABSTRACT FROM AUTHOR]

Background: In contrast to traditional impact-based testing, the Dynamic Tensile Tear Test (DT3) has shown great potential to characterise high-grade pipeline steels as it mimics the in-field pipeline conditions. However, material characterisation using the DT3 method has only been performed at room temperature and lower-shelf characterisation has not yet been investigated. Objective: This study investigates a solution to perform low-temperature characterisation and analyse dynamic brittle fracture behaviour using the DT3 setup. Methods: A large-surface spray cooling system using liquid nitrogen was constructed and implemented onto the DT3 system. Cooling performance and temperature uniformity were assessed using thermocouples across a large surface area up to 412 cm2 (2 × 206 cm2). Numerical validation was performed through Finite Element (FE) analysis using the Modified Bai-Wierzbicki (MBW) material model. A combined stress–strain criterion was used to take into account cleavage failure. Results: Temperatures down to -125 °C were reached using the spray cooling system and a fracture tests was performed at -80 °C. The obtained data and resulting fracture surface indicated clear brittle fracture behaviour. An average crack velocity of 152 m/s was measured, which is in the same order of magnitude associated with crack velocities observed in large-scale testing. Conclusions: The constructed spray cooling system proved to be capable of cooling a large volume down to cryogenic temperatures while achieving acceptable temperature uniformity. Lower-shelf characterisation of X70 grade pipeline steel was achieved using the DT3 method and a good correlation was obtained between numerical data and experimental observations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current study focuses on spray cooling applied to the heat exchange components of a cooling tower. An optimization of such processes is attempted by assessing different spray flow rates and droplet sizes. For simplicity, the heat exchanger of the cooling tower is modeled as a horizontal round tube and a cooling tower spray cooling model is developed accordingly using a computational fluid dynamics (CFD) software. The study examines the influence of varying spray flow rates and droplet sizes on the heat flow intensity between the liquid layer on the surface of the cylindrical tube and the surrounding air, taking into account the number of nozzles. It is observed that on increasing the spray flow strength, the heat flow intensity and extent of the liquid film in the system are enhanced accordingly. Moreover, the magnitude of droplet size significantly impacts heat transfer. A larger droplet size decreases evaporation in the air and enhances the deposition of droplets on the round tube. This facilitates the creation of the liquid film and enhances the passage of heat between the liquid film and air. Increasing the number of nozzles, while maintaining a constant spray flow rate, results in a decrease in the flow rate of each individual nozzle. This decrease is not favorable in terms of heat transfer. Graphic Abstract [ABSTRACT FROM AUTHOR]

Against the backdrop of climate policy goals and the EU's aim for a resource-efficient economy, the foundry industry must rethink product range, energy consumption, and production technologies. Light metal casting, which is performed through processes like gravity die casting and high-pressure die casting, requires effective thermal management, which is crucial for optimising mould filling, solidification, cycle times, and part quality. Against this background, this study presents the development and characterisation of a cooling system that completely dispenses with energy-intensive heating/cooling devices. The system is based on a mask shape combined with internal spray cooling. This paper shows the simulation workflow for developing the mould mask and the design of the cooling system and compares the performance with conventional temperature control using channels. In the tests, an 82% higher cooling rate was achieved with Cool-Spray than with conventional temperature control, which was approx. 2.5 mm below the cavity surface. In addition to the more dynamic temperature control, the potential for process control was utilised, and the component quality of the test part was significantly improved compared to conventional temperature control. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-strength concrete (HSC) boasts excellent compressive strength and durability, making it a popular choice in various engineering applications. However, under the impact of high temperatures, HSC tends to crack easily, so it is combined with polyvinyl alcohol fiber (PVA fiber) to explore its engineering application prospect. This paper investigated the physical and mechanical characteristics of HSC reinforced with PVA fibers subjected to different heating temperatures and cooling techniques. The experimental results reveal a correlation between rising temperatures and observable changes in the specimens: a progressively lighter surface hue, an augmented frequency of cracking, and a considerable escalation in the mass loss rate, particularly after the temperature exceeds 400 °C. Regarding mechanical properties, the dynamic elastic modulus and compressive and flexural strength all decrease as the heating temperature increases. As the amount of PVA fiber rises while maintaining a steady temperature, these measurements initially show an increase followed by a decrease. The fiber contents yielding the best compressive and flexural strength are 0.2% and 0.3%, in that order. Considering the influence of cooling methods, water spray cooling has a greater impact on physical and mechanical properties than natural cooling. Furthermore, SEM was employed to scrutinize the microstructure of HSC, enhancing comprehension of the alterations in its physical and mechanical characteristics. The findings of this research offer significant information regarding the high-temperature behavior of HSC, serving as a valuable resource for guiding the design, building, and upkeep of structures that incorporate HSC. Additionally, this study will aid in advancing the progress and utilization of HSC technology. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The performance optimisation of spray cooling heat transfer systems has been identified as a significant step in improving process efficiency, and the application of machine learning tools is a recent development that has enhanced this. This study aims to maximise the heat transfer coefficient for spray cooling at low heat flux levels. The effects of nozzle inclination angle, water pressure, and spray height on heat transfer coefficient were studied. Taguchi L27 orthogonal array technique was used to perform the experiments. A maximum heat transfer coefficient of 181.4 kW/m2K was obtained at a nozzle inclination angle of 60°, spray height of 4 cm, and water pressure of 15 psi. Analysis of variance was performed to find the significance of each variable and its interactions. The results show that for the maximum heat transfer coefficient (181.4 kW/m2K), the optimum levels of the independent variables were A3H1P3, i.e., the highest level of nozzle inclination angle (60°), the lowest level of spray height (4 cm), and the highest level of water pressure (15 psi). The support vector machine outperformed the Random Forest algorithm and Multiple Regression analysis regarding prediction accuracy with a maximum error of 0.15 % and root mean squared error of 0.01.

Near-isothermal compression and expansion may be accomplished by injecting water droplets into the air during the process to increase the overall efficiency. However, little is known about the relationship between spray system parameters and compressed air energy storage (CAES). Furthermore, the experiments about CAES using spray-based heat transfer have not been investigated. The aim of this paper is to study the relationship between the performance of CAES and the spray system parameters by experimentally. The parameters including the spray closing time, the spray opening time, and the nozzle diameter are discussed. Results show that under the same operating conditions, the maximum air pressure in compression chamber reach to constant value when the spray closing time is 0.6 seconds, and spraying water mist within 0.6-1.2 seconds has no heat exchange effect on the air in the cylinder. During the compression process, the smaller the nozzle diameter is, the higher maximum pressure in compression chamber is. During the expansion process, if we ignore the energy consumption of spray system, the larger the nozzle diameter is, the more the expansion output is. Further investigation is recommended to optimize spray parameters based on different CAES systems. [ABSTRACT FROM AUTHOR]

In the case of products made of steel, the presence of an oxide layer, which is formed during the steel production process as a result of high temperature, has a significant impact on the process of heat removal from the surface of the cooled material. For this reason, it is necessary to take into account the presence of the oxide layer in mathematical and numerical models used to simulate the distribution of the temperature field in cooled steel products. These models are based on the boundary conditions identified for given production conditions. This paper presents a comparison of the results of the identification of the boundary condition during water spray cooling of Armco iron with the use of the inverse solution. Numerical calculations were carried out using two models of heat conduction. In the first model, the presence of an oxide layer with different thermophysical properties than the base material (Armco iron) was taken into account. The second model assumed no oxide layer on the cooled Armco iron surface. It was found that the inverse solution obtained in the case of the heat conduction model taking into account the thickness of the oxide layer is correct in time and as a function of temperature. Thus, the boundary condition model obtained as a function of temperature is universal. However, this model requires an additional layer of oxides with different thermophysical properties than the base material to be included in the finite element model (FEM). Based on the conducted uncertainty tests of the inverse solution, it was found that the results of the determined boundary condition in the absence of the oxide layer on the cooled surface are subject to an error higher than 10% in comparison to the maximum reference value of the heat transfer coefficient. [ABSTRACT FROM AUTHOR]

AbstractLiquid nitrogen spray cooling is crucial in cryogenic wind tunnels, while the understanding of its basic phenomenon, liquid nitrogen droplet impact, remains elusive. In this study, a numerical model of a liquid nitrogen droplet impacting on a liquid nitrogen film is established, and the impact mechanisms and influencing factors are analyzed. The dynamic behavior of the liquid nitrogen droplets reveals that as the dimensionless liquid film thickness varies from 0.1 to 0.8, the droplet impact behavior changes from deposition, and crown formation to splash with the Weber number increasing from 0 to 1000. The variation of the dimensionless crown diameter with the dimensionless time solely negatively correlated with liquid film thickness. The maximum dimensionless crown height increases approximately linearly with the Weber number. The splash characteristics indicate that the lower surface tension and viscosity of liquid nitrogen make the droplet easier to exhibit splash as compared with water droplets. As the dimensionless liquid film thickness increases from 0.1 to 0.4, the critical Weber number enabling splash to occur increases from 170 to 375, indicating that a thick liquid film suppresses the splash. [ABSTRACT FROM AUTHOR]

To effectively reduce residual stresses in GH4169 workpieces, thus enhancing fatigue strength and operational lifespan, this study investigates the influence of spray cooling parameters on surface residual stresses during GH4169 turning in spray cooling conditions, utilizing both simulation and experimental approaches. A simulation model of residual stresses was established using finite element analysis when GH4169 was cut in spray cooling. The effects of spray pressure and flow rate on residual tensile stresses were analyzed. The analysis reveals that with increasing spray pressure, residual tensile stresses show a decreasing trend, gradually stabilizing. Conversely, with an increasing spray flow rate, residual tensile stresses initially decrease and then increase. The turning experiments of GH4169 were conducted under different spray parameters. After the experiment, the workpiece was sectioned and analyzed for residual stresses using X-ray diffraction instrumentation. The value residual stress measured closely matched those of simulation, with a relative error within 6%, validating the accuracy of the simulation model and confirming the appropriateness of parameter settings. These results contribute to the further promotion of spray cooling technology and facilitate the rational selection of spray parameters. [ABSTRACT FROM AUTHOR]

The space exploration from a low earth orbit to a high earth orbit, then to Moon, Mars, and possibly asteroids and moons of other planets is one of the biggest challenges for scientists and engineers for the new millennium. The enabling of in-space cryogenic rocket engines and the Lower-Earth-Orbit (LEO) cryogenic fuel depots for these future manned and robotic space exploration missions begins with the technology development of advanced cryogenic thermal-fluid management systems for the propellant transfer line and storage tank system. One of the key thermal-fluid management operations is the chilldown and filling of the propellant storage tank in space. As a result, highly energy efficient, breakthrough concepts for quenching heat transfer to conserve and minimize the cryogen consumption during chilldown have become the focus of engineering research and development, especially for the deep-space mission to Mars. In this paper, we introduce such thermal transport concepts and demonstrate their feasibilities in space for cryogenic propellant storage tank chilldown and filling in a simulated space microgravity condition on board an aircraft flying a parabolic trajectory. In order to maximize the storage tank chilldown thermal efficiency for the least amount of required cryogen consumption, the breakthrough quenching heat transfer concepts developed include the combination of charge-hold-vent (CHV) and no-vent-hold (NVF). The completed flight experiments successfully demonstrated the feasibility of the concepts and discovered that spray cooling combined with hold and vent is more efficient than the pure spray cooling for storage tank chilldown in microgravity. In microgravity, the data shows that the CHV thermal efficiency can reach 39.5%. The CHV efficiency in microgravity is 6.9% lower than that in terrestrial gravity. We also found that pulsing the spray can increase CHV efficiency by 6.1% in microgravity. [ABSTRACT FROM AUTHOR]

Dry ice pulsed sublimation spray cooling (PSSCDI) is an innovative, efficient, energy-saving, and fast cooling method for the thermal management of chip-level electronic components with high thermal load in the aerospace field. Aiming at the heat transfer mechanism of dry ice sublimation spray cooling, a heat transfer model of pulsed dry ice sublimation spray cooling based on flow discretization is proposed in this paper. According to the heat transfer mechanism and the formation mechanism of dry ice reflected by the Joule–Thomson effect, the experimental platform of pulsed dry ice sublimation spray cooling was designed and built. The relationship between spray height, spray flow rate, and spray cone Angle was determined by experiments, and the best spray height was determined. The effects of mass flow rate, pulse period, and duty cycle on heat transfer characteristics of pulsed dry ice sublimation spray were investigated experimentally. The experimental results show that the instantaneous temperature change process of simulated heat source under different working conditions can be divided into three stages: heating, cooling, and constant temperature. The heat flux and heat transfer coefficient of pulsed dry ice sublimation spray cooling under high heat load increase with the increase of the duty ratio and mass flow of dry ice spray, but decrease with the increase of pulse period. However, the heat flux of the duty cycle and heat transfer coefficient of the duty cycle decrease with the increase of duty cycle, which indicates that under the premise of considering dry ice consumption, a lower duty cycle will make pulsed dry ice spray cooling have a higher heat transfer efficiency. When the mass flow rate of dry ice spray is 13 g/s, the pulse period is 0.2 s, the duty cycle is 50 %, the heating power is 40W, the relative optimal cooling heat flux is 48 W/cm2, and the relative optimal heat transfer coefficient is 5400 W/(m2·K). [ABSTRACT FROM AUTHOR]

The finite element method was taken to simulate the heat transfer characteristics and capacity of the online cooling equipment of a 3500 mm medium thickness plate production line. The cooling field on the steel plate surface could be divided into the impact zone and the wall jet zone after cooling water was sprayed on the surface of the steel plate. The impact zone had an intense heat transfer capacity because of the static pressure and the high radial velocity of cooling water. The maximum heat transfer coefficient (HTC) in the impact zone of spray and laminar cooling equipment could reach 20,334 and 10,096 W/(m2 °C), respectively. In the wall jet zone, the radial velocity of cooling water was the main factor affecting the heat transfer capacity. With the decrease in velocity, the HTC decreased gradually. There is a linear relationship between the average HTC and the water flow. The average HTCs of spray and laminar cooling equipment in the common range of water flow were 5904–7255 W/(m2 °C) and 3012–3369 W/(m2 °C), respectively. The HTCs were verified in the 3500 mm medium thickness plate production line. [ABSTRACT FROM AUTHOR]

The spray cooling and tempering technology has a series of advantages, such as improving the tempering quality and reducing energy consumption. In order to optimize the tempering technological parameters, it is necessary to accurately control the thermal history and temperature distribution of a hot glass surface during spray cooling. However, measuring the inner temperature of tempered glass proved challenging. The Euler-Lagrangian approach was utilized for simulating the process of spray cooling the glass surface. To validate the accuracy of model predictions, experimental studies were conducted on the tempering of glass by a single nozzle. The numerical outcomes exhibit strong correspondence with the experimental findings. Building upon the foundation, the study analyzed the heat transfer mechanisms in different states including film boiling, nucleate boiling, and forced convection. Subsequently, the effects of spray distance, spray loading fraction, spray pressure, and final cooling temperature on the heat transfer rate and temperature homogeneity were discussed. The results revealed that reducing the spray distance, increasing the spray loading fraction and spray pressure can improve the cooling rate and reduce energy consumption, but it aggravated the uneven distribution of temperature over the glass surface. Moderately increasing the final cooling temperature had little effect on the tempering quality of glass, but it significantly reduced the energy consumption for spray cooling. Within the experimental range, the optimal final cooling temperature was 573.15 K.

Spray cooling is an effective method and thus finds many applications, including thermal management and energy production. In this regard, spray cooling with flat sprays is particularly crucial in applications with space constraints, as it efficiently dissipates heat while conforming to limited spatial requirements. Flat sprays ensure a wide yet uniform distribution of coolant, making it ideal for cooling systems in compact and densely packed environments. Motivated by these advantages, in this study, we performed an experimental study on the effect of major flat spray parameters, which are the spray flow rate (160 mL/min), spray upstream pressure (2.5 and 5.0 bars), spray angle (0, 30, and 90°), spray distance (3 and 10 cm), spray temperature (23 and 61 °C) and wall heat flux (10–100 W/cm2), on the two-phase heat transfer performance. According to the results, unlike full cone nozzles, the spray distance enhances heat transfer. While the cooling rate increased with the upstream pressure, the inlet temperature had a deteriorating effect on the heat transfer performance of the system. The results also indicated that the heat transfer rate decreased with the spray angle. The spray angle-induced effect on the system performance diminished with the spray pressure and temperature. The obtained results were used to develop two correlations for single phase and nucleate boiling heat transfer in flat sprays. The findings of this study suggest that flat sprays, with their significantly lower flow rates compared to full spray cone nozzles, effectively meet the requirements for direct thermal management by offering precise control, reduced fluid consumption, and enhanced efficiency.

This document is an editorial from the journal Frontiers in Sustainable Food Systems. It discusses the use of green technologies for the extraction of bioactive compounds and their application in the food industry. The editorial highlights the importance of new extraction methods that minimize the loss of bioactive compounds and increase yield. It also explores the use of nanotechnology to produce nanomaterials that can encapsulate or protect bioactive compounds for potential applications in the food industry. The editorial includes references to several research articles that focus on green extraction techniques and the encapsulation of bioactive compounds. [Extracted from the article]

Droplet size and distribution uniformity of sprinklers significantly affect production safety in the processes of steam temperature and pressure reduction within nuclear power, and other high-temperature, high-pressure industries. In industrial sprays with high flow rates and low pressure drops, reducing droplet size poses additional challenges, making improved spray uniformity essential for enhancing heat transfer. This study designed and produced a set of swirling-straight sprinklers, tested their flow characteristics and liquid distribution, and proposed a highly uniform spray mode involving swirl jet interaction mixing. The discharge coefficient (Cd) changes indicated that enlarging the jet channel area diminishes the amplification effect, suggesting a trade-off in industrial high flow sprinkler design. A detailed evaluation and analysis method of the spray process, which is superior to the use of a single uniformity parameter, is proposed based on Gaussian function peak fitting method. It has been observed that the relationship between the Gaussian fitting parameters and the pressure drop of the sprinkler tends to be linear. This discovery provides a new basis for designing nozzles with low pressure drop, high flow rates, and uniform distribution. The findings contribute to the optimization of spray performance and provide valuable data for computational fluid dynamics model verification.

The demand for higher power density in electrical machines necessitates advanced cooling strategies. Spray cooling emerges as a promising and relatively straightforward technology, albeit involving complex physics. In this paper, a quasi-3D thermal finite-element model of stator winding is created by the extrusion of a 2D cross-sectional finite-element model along the winding direction. The cooling effects of the spray impact are simulated as a heat flux that uses an impedance boundary condition at the surface of the winding overhang. The results confirm the advantageous performance of spray cooling, indicating that it may enable a tenfold increase in power density compared to standard air- or water-cooled machines.

Electrospray deposition (ESD) is a technique with emerging relevance for applications requiring micro‐/nano‐scaled coatings. Self‐limiting electrospray deposition (SLED) is a regime of ESD where upon satisfying the criteria for self‐limiting behavior, the charge buildup of the material will eventually begin to repel itself until an asymptotic thickness is achieved, based primarily on the properties of the spray solution and deposited material. This work focuses on controlling the coating thickness further to achieve sub‐micron thicknesses. By applying a voltage bias of the same polarity of the spray onto the target substrate while providing a secondary grounded surface, the thickness of a payload can be manipulated for thinner and more precise thicknesses. The magnitude of the voltage bias is varied to show the effect of voltage bias on thickness, and 2‐D and 3‐D structures are used to demonstrate the generality of this technique for complex substrates. The results show how SLED can be included as a potential alternative for conformal coatings deposited at ambient conditions at the sub‐micron scale. [ABSTRACT FROM AUTHOR]

Based on the electromagnetic thermal coupling analysis method, the cooling performance of different motor cooling models and the influence of key parameters of the cooling system on the cooling effect of the motor are investigated. First, the losses of various parts of the permanent magnet synchronous motors are obtained through electromagnetic calculations; the analysis results show that the stator core loss, winding copper loss, and eddy current loss of permanent magnets exceed 95% of the total loss of the motor. Second, the cooling performance of the three motor was compared and analyzed. The axial housing liquid cooling and oil spray cooling (Model B) has a better cooling performance and a higher cooling efficiency. Compared with the other two motor models, Model B can reduce the time to reach steady-state temperature by about 81.8%. Then the effects of coolant volume flow rate, coolant inlet temperature, and ambient temperature on the cooling effect of the motor are investigated. The results show that within a certain range, the rate of coolant inlet temperature change is approximately proportional to the internal temperature rise of the motor. The oil spray cooling system of Model B is less affected by ambient temperature and can be used for motor cooling in complex environments. The results of this study can provide a useful guidance for the design of the cooling system and the selection of coolant volume flow rate for oil-cooling motor with hairpin windings. [ABSTRACT FROM AUTHOR]

Industrial growth has led to increased electronic component integration, resulting in higher working temperatures and technological failures. Cryogen spray cooling (CSC) could reach cryogenic temperatures with fast-responding, but its heat transfer limitation due to liquid film deposition is potentially challenging. In this study, CSC cooling is incorporated with either a cold air jet (CAJ) or a sweeping jet (SWJ) to enhance heat and fluid flow. A K-type thermocouple is used for measuring the surface temperature, while the improved Duhamel theorem is used to estimate the heat flux. The spray and film intensities are recorded through the Mie-scattering methodology via high-speed camera. The results demonstrated that the CAJ/SWJ exhibited a significant reduction in surface temperature and film intensity, enhanced heat dissipation and spray efficiency compared to CSC cooling. More precisely, it demonstrated a 26%–36% heat transfer coefficient improvement, along with a 52% increase in the corresponding time of the critical heat flux. Meanwhile, the CAJ/SWJ intensifies heat transfer during film and transition boiling, inspired by the fast liquid film evaporations. In contrast, the SWJ is much preferred due to its wider and stable coolant coverage throughout film evaporation, as seen by its greater heat transfer coefficient. The combined results demonstrated the need to promptly eliminate the deposited film, as it holds the potential to serve as a pivotal resolution for the advancement of thermal management technology. [ABSTRACT FROM AUTHOR]

Regeneratively cooled scramjets are successfully used as propulsion devices in hypersonic vehicles. During operation, scramjets experience acceleration. This special process causes a dynamic flow process, and heat transfer in the cooling channel commonly occurs, which may cause hazards and control difficulties for scramjets. A dynamic numerical model with a modified heat transfer coefficient calculation method was established to study the transient flow and heat transfer processes in a cooling channel. The dynamic characteristics of the flow and heat transfer under different conditions were calculated and are discussed, including the changes in the inlet fuel mass flow, heat flux, and pressure working conditions. The results indicate that the stable time of the cooling channel outlet fuel temperature is related to the rate of change in the inlet mass flow and heat flux. The stable time of the outlet fuel temperature under decreasing heat flux working conditions was approximately 12.5 s. These results summarize the dynamic flow and heat transfer characteristics, which are significant for designing cooling channels in scramjets. [ABSTRACT FROM AUTHOR]

Spray cooling is an effective heat dissipation technology and is widely used in the heat dissipation of encapsulated structures, but most of the research has only focused on the heat transfer performance itself and has lacked the analysis of surface stress and deformation. In this paper, a thermal stress coupling model was established under spray conditions, and the influence of spray parameters such as the spray height, spray flow, and nozzle inclination on heat transfer, surface stress, and deformation were studied. The result indicated that the lower the surface temperature, the smaller the stress and deformation. What is more, there was an optimal spray height (15 mm) to achieve the best heat transfer, and the surface stress and deformation were also minimal at the same time which the values were 28.97 MPa and 4.24 × 10−3 mm, respectively. The larger the spray flow rate, the better the heat transfer effect and the smaller the surface stress and deformation. When the spray flow rate was 24.480 L/h, the minimum values of surface stress and deformation were 25.42 MPa and 3.89 × 10−3 mm, respectively. The uniformity of surface stress distribution could be effectively improved with the increase in flow rate. Compared to 10 and 15 degree nozzle inclination, when the nozzle was perpendicular to the cooling surface, the surface stress and deformation were minimal. [ABSTRACT FROM AUTHOR]

Light Emitting Diodes (LEDs) is one of the newest ways to light up outdoor areas such as streets, stadiums, airports, military bases, harbors, and high mast towers. The main reason for the high focus is power consumption with better brightness. Even though LEDs have so many benefits, researchers should focus on better managing temperatures as the main reason behind the failure of LEDs is overheating. In this article, modern research trends like using heat pipes filled with nanofluids, ionic winds, spray cooling, use of fins, refrigerants, and oil cooling are focused on and discussed concerning LEDs, solar stills, electric vehicle batteries, and different heat transfer devices to develop a new way to handle the heat from higher-wattage LEDs. There is a research thrust in the field of more than one nanoparticle in the base fluid, and its proportions are not analyzed during LEDs cooling study using a heat pipe. It is necessary to control the heat using a more effective technique. Heat pipe with nanofluid is a more efficient, compact, and cost-effective cooling device o reduce LED failure due to higher heat flux. Hence, it is promising to use nanofluid-filled heat pipes to serve the purpose of the life span enhancement of LEDs. [ABSTRACT FROM AUTHOR]