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Experimental studies to determine the average heat transfer coefficient (hav) and frictional pressure gradient (ΔPF/L) of R-513A flowing through a horizontal smooth tube during evaporation are investigated. The experimental setup comprises a double-tube heat exchanger with supplied water circulating inside the annulus in the opposite direction. The average heat transfer coefficient ratio (hav,513A/hav,134a) and frictional pressure gradient ratio ((ΔPF/L)513A/((ΔPF/L)134a) of R-513A and R-134a were compared in this study. The experimental results show hav and ΔPF/L obtained from R-513A are about 0.96 and 0.95 times lower than R-134a, respectively. For R-513A, the hav is lower due to a decreased convective effect, whereas the lower ΔPF/L is due to decreased flow resistance. The Nusselt number (Nu) is higher than R-134a, whereas the two-phase friction factor (fTP) is slightly higher. [ABSTRACT FROM AUTHOR]

We propose a novel technique that combines physics-informed machine learning (PIML) with the wall-adapting local eddy viscosity model for predicting flow patterns over time. In order to generate loss functions for turbulence flow and calculate dissipation rates within the domain, a new form of machine learning-based WALE-LES model includes updating the boundary matrix and tensor of component velocity and pressure tensors over time. By utilizing boundary conditions, Navier-Stokes-based equations will be discretized via automatic differentiation in PIML. We present a novel point cloud-based method for pore-scale porous media (PSPM) for the first time. This method transforms complex geometry into a matrix of data based on a point cloud. As a result of this method, boundary conditions are included in transient calculations. We modified the standard form of momentum equations to obtain the loss function for flows passing through a PSPM. According to the findings, high-fidelity numerical simulation and PIML prediction results are very similar in pressure and velocity. Additionally, this method can reduce calculation costs by up to 41% compared to the standard method. [ABSTRACT FROM AUTHOR]

For several years, air pollution from internal combustion engines has become a significant issue in the transportation sector. Hence, electric vehicles (EVs) have been developed to reduce emissions. Lithium-ion batteries are the most important component in EVs which are used for energy storage. Generally, a battery generates some amount of heat during charging and discharging which results in an increased battery temperature. It has a direct impact on the battery's performance and its life span. When the battery temperature rises excessively beyond an appropriate temperature, it may explode. To keep the battery temperature within a recommended range of 25 °C–40 °C with a temperature difference between cells less than 5 °C, the use of a battery thermal management system (BTMS) is necessary. There are several types of battery cooling systems such as liquid cooling, air cooling, and phase-change material (PCM) cooling. Therefore, the goal of this study is to numerically investigate the improvement of cooling performance when water-based nanofluids are used as a working fluid in a liquid-cooled BTMS using the ANSYS Fluent program. The accuracy of the simulation model was validated with the experimental results using battery surface temperature. The result showed that the maximum deviation between the simulation and the experiment was 1.83%, which is acceptable. Furthermore, three different geometries of cooling flow channels (Model A, Model B, and Model C) were designed to investigate the capability of heat rejection from the batteries. It was seen that the cooling system of Model C using pure water as a coolant had the highest heat rejection per unit mass of coolant. Then, adding nanoparticles into pure water was implemented in Model C. The study discovered that using water/SiC (98:2) as a working fluid reduced the maximum temperature of the battery by up to 2.285°C at an inlet velocity of 0.033 m/s. Nonetheless, the battery temperature was still beyond the recommended range. Therefore, to control the maximum temperature in a safe range, the inlet velocity of fluid flow was increased to 0.066 m/s to enhance the heat transfer. The result showed that using water/SiC (99:1) could control the maximum temperature at 28°C with a temperature difference of 4.8°C, which is acceptable. [ABSTRACT FROM AUTHOR]

A mini-channel heat sink has been developed to cool small devices, such as electronic devices and central processing units (CPUs). Due to the increasing demand of electric vehicles (EVs), a mini-channel heat sink has been applied in a battery cooling system that must be continually improved to ensure safe and efficient battery use. In spite of the major drawback of high-pressure drop, the mini-channel heat sink is an area of great interest among researchers because it can provide high thermal performance. In regard to reducing pressure drops, a dendritic channel has been developed to alleviate the high-pressure drop problem and provide a better temperature distribution. This paper is a proposal review related to dendritic mini-channel heat sink and its applications in battery cooling systems. [ABSTRACT FROM AUTHOR]

We investigated free convective heat transfer within an electronics cooling system with a metallic porous extension. The finite element method is used to solve the associated transport equations. Changing fluidic and geometric parameters allows examination of the isotherm contour, streamlines, and heater average temperature. It is found that the presence of a metallic porous block causes higher temperature up to a greater height of the domain than the absence of a porous material. The strength of the vortex is greater in the case of porous extension than in the case of no extension. Furthermore, the effect of Darcy number (Da) on average heater temperature (θavg) is negligible. The value of θavg decreases as the height of the porous extension increases. Inferences obtained from this analysis are expected to provide an adequate basis for the effective design of small-scale thermal management devices/systems that are typically used in electronic cooling systems. [ABSTRACT FROM AUTHOR]

We investigated the natural convective heat transfer characteristics within a solar power plant having a built-in aluminium metallic porous block and by using MWCNT-Fe3O4/water hybrid nanofluid. The Darcy-Brinkmann-Forchheimer model is used to describe the porous media flow field as well as the energy equation. When a metallic porous block is integrated to the plant, the average Nusselt number becomes significantly higher and increases with increasing Darcy numbers. The use of a hybrid nanofluid causes higher heat transfer rate compared to a pure fluid. Inferences obtained from this analysis are expected to provide a design basis of a modern solar plant intended for augmented energy recovery. [ABSTRACT FROM AUTHOR]