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In this research study, we delve into the analysis of two-dimensional boundary layer incompressible viscous flow of blood based nanofluids, incorporating a couple stress model. This investigation encompasses considerations of heat transmission and viscous dissipation effects. Specifically, focus on a particular type of nanoparticle, Magnesium oxide (MgO), dispersed in blood, the base fluid. By employing suitable similarity transformations, transform a set of partial differential equations (PDEs) into nonlinear ordinary differential equations (ODEs). To leverage the Homotopy Analysis Approach (HAM) to solve this system of equations. This study discerns the impacts of various factors on temperature and velocity distributions. Visualization through graphs depicting nanoparticle volume concentration, magnetic field strength, couple stress parameter, Eckert number, and Prandtl number aids in presenting our findings. These insights illuminate the intricate interplay among different parameters and offer insights for enhancing heat transfer in blood-based nanofluids. Additionally, scrutinize the thermal performance of the blood-based nanofluid, assessing the Nusselt number and local skin friction coefficient. Such analysis holds significance for ensuring patient safety and treatment efficacy, particularly in medical procedures involving blood circulation, where mixed convection plays a pivotal role. Understanding these dynamics is crucial for the design and optimization of various medical devices and therapies, ensuring optimal temperature maintenance during blood circulation-related operations.

The main objective of this research paper is to scrutinize the entropy generation(EG) in the bioconvective flow of micropolar fluid by porous surface of a stretched sheet. Mixed convection effects are considered. Thermal radiation, internal fluid friction, Joule heating, and heat generation aspects are accounted for in the energy relation. Mass concentration relation is developed because of the binary chemical reactions associated with Arrhenius kinetics. The governing equations for the micropolar fluid are developed based on Buongiorno's model with the help of boundary layer restrictions. By invoking the transformation procedure, dimensional model is made dimensionless. The well-known shooting technique RKF-45 in Mathematica software is implemented to solve the transformed equations. Performance of micropolar fluid velocities, thermal field, entropy generation, mass concentration, Bejan number, and motile density versus influential variables are highlighted. Furthermore, the intensity of skin friction, Nusselt quantity, motile density, and Sherwood number is computed and analyzed. It is observed that the rate of EG improves while the Bejan number diminishes versus higher Brinkman number, and diffusion parameter due to gyrotactic microorganisms. Magnitude of heat transfer rate boosts through higher Γ, Qs, Ec, Ha and Rd at an average percentage of 44, 82, 189, 156 respectively.

Tangent hyperbolic nanofluid enhances heat transfer in various applications, such as cooling systems and electronics, due to its improved thermal conductivity and stability. Therefore current analysis explore the inspiration of joule heating and activation energy on Tangent hyperbolic nanofluid in the existence of motile microorganism. For motivation the impact of Riga plate, variable thermal conductivity, thermal radiation and heat source are the part of this investigation. The appropriate similarity variable are assumed to transformed the set of governing partial differential equations considering the influential effects of Joule heating and activation energy into ordinary differential equations. MATLAB via bvp5c tool is engaged to solve resulting system. The effects of dimensionless parameters like Weissenberg number We, Power-law index Power-law index n, Hartmann number M, thermal radiation Rd, Brownian motion Nb, Prandtl number Pr, Peclet number Pe and thermophoresis Nt on velocity f′(η) temperature θ(η), volumetric concentration of nano particles φ(η) and density profile χ(η) are displayed in graphical and tabulated form. It is noted that improving the Weissenberg number We, Hartmann number M and Power-law index n, the speed of flow decreased. By increasing value of Prandtl number Pr the temperature curve reduced, inverse relation is observed for growing value of Rd.

Jeffrey fluids have found vast applications in industries and engineering along with their rheological properties. This article investigates the heat and fluid flow within the frame of the nonlinear thermal radiation and non-Fourier heat flux model on Jeffrey nanofluid over an inclined permeable stretched cylinder through saturated porous medium. In addition, non-uniform heat generation/absorption, nonlinear thermal radiation, thermal stratification, and homogeneous/heterogeneous reactions are accounted. Porous medium is characterized through nonlinear Darcy-Forchheimer relation. Shooting method is employed in conjunction with Runge-Kutta-Fehlberg method to solve nonlinear ODEs. The effects of flow variables involved in velocity, temperature and concentration profiles are deliberated through graphs. It is evident from obtained results that the temperature field rises with thermal radiation parameter and space dependent heat generation/absorption parameter. Local Nusselt number has same enhancing attitude towards the thermal relaxation time (0.7443≤−Nˆuz(Rez)−12≤0.7857 for0.2≤δe≤0.6) and thermal stratification parameter (0.7239≤−Nˆuz(Rez)−12≤0.7689for0.2≤S1≤0.6). The exactness of the solution and F′(ξ) variation is verified by comparison with already published literature. The computed results are of great interest in cooling of nuclear reactors. Viscoelastic stuff are generally employed in mats, car shields, computer hard drives and other protective paddings. Synthetic materials can work as the lubricant for an osteoarthritic joint.

The engineers are fascinated in fluid flows and heat transfer in engineering optics and devices. For such purposes, fluid flows are computed in different geometries. The engineers normally look for reduced heat transfer, enhanced cooling rate and reduced friction drag. Thus, the focus of the present article is to undertake the flow of viscous or Newtonian fluid through joined cavities which is very important in many engineering fields. The Navier-Stokes equations are operated for studying behavior of flow, while Fourier's law of heat conduction is employed for the analysis of heat flow in connected cavities. The consequences show that high pressure, lowest velocity and high temperature are observed at the thin connection of cavities.

The effect of nanoparticle volume concentration on the thermo-physical characteristics of hybrid nanofluid has been a major area of study. Since hybrid nanofluid combines the chmical and physical properties of nanoparticles in a useful way, they overcome the limitations of mono nanofluids. The goal of this work is to examine how the Cu-Al2O3 nanoparticles affect the thermal conductivity, dynamic viscosity and rheological characteristics of kerosene oil-based hybrid nanofluids. The focus on this study is to analyze the magnetized hybrid nanofluid flow over a stretching/shrinking cylinder with the influence of different physical effects. For this, a mathematical model of a hybrid nanofluid is formulated in the form of PDEs. Then these PDEs are converted into ODEs by applying similarity conversion and tackled numerically. To understand the flow behavior, friction drag enhancement, thermal distribution, and heat transport phenomenon of Cu-Al2O3/kerosene oil, the graphical results are sketched. The results show that nanoparticle inclusion boosts the skin friction coefficient and heat transport rate. Here, ϕ1 , ϕ2 symbolize the Copper ϕCu and Aluminum Oxide ϕAl2O3 volume fractions, respectively. It is discovered that the values of Re1/2Cf and Re−1/2Nu grow when the values of nanoparticles volume fractions ϕ1 , ϕ2 increase. Further, increasing magnetic strength lowers the fluid velocity and increases the thermal distribution of the liquid. Additionally, the temperature of the liquid is increased by rising Biot number and thermal radiation, respectively.

In this paper, numerical simulation for the two-dimensional flow of tangent hyperbolic fluid in the manifestation of nanoparticles, heat source and joule heating is considered. For motivation of problem, the role of Riga plate is investigated. Chemical reaction and Brownian motion are the parts of the analysis. The set of PDEs of Tangent hyperbolic nanofluids with swimming germs is converted in to couple of ODEs by employing well-known approach namely shooting scheme. The resulting highly nonlinear and coupled ODEs are solved by using ND solve tool of Wolfram Mathematica 11. Numerical outcome of involving parameters of interest like Lewis number Le, Prandtl number Pr, Chemical diffusion k, Peclet number Pe, Weissenberg number We, Bioconvection Lewis number Lb, nonlinear radiation, Biot number Bi, modified Hartmann number Q and magnetic parameter M on tangent hyperbolic nanofluids velocity f″, temperature θ, concentration φ and density of germs distribution are discussed in the form of graphical trend and tables. We professed that the speed of fluid degenerated for the increasing value of power-law index n and magnetic parameter M. The Nusselt number growths for growing values of the thermophoresis parameter Nt, Biot number Bi and radiation parameter Nr.

This numerical work aims to improve combustion efficiency and thermal efficiency by modifying the piston shape and crevice volume ratio of the HCCI engine operated under excessively lean air-fuel mixture conditions for power generation employment. The baseline piston, optimized for the diesel engine, gives strong reverse squish flow during the expansion stroke, causing a reduction in the efficiency of the engine. Therefore, the flow field in the squish area of the piston bowl should be weakened to facilitate auto-ignition at different points to boost the burning rate. Hence, the baseline piston shape was modified by bringing down the piston bowl depth and reducing the squish area ratio from 34% to 5% with a constant compression ratio. Crevice volume ratio Vcrevice/VTDC is also optimized for the HCCI engine to achieve high performance. All calculations are executed at MBT conditions by changing the inlet temperature of the mixture. Finally, the computational model results are validated with literature data. The results indicate that combustion phasing advances by changing the piston shape, and it also reports that the highest engine combustion efficiency of about 96%, 97%, and 99% are achieved by changing the piston shape and reducing the 40% crevice volume ratio of the engine, at low load, medium load, and high loads, respectively. The results also show that thermal efficiency is improved from 40% to 46% at low load while enhancing from 36 to 38.5% at 10 bar IMEP, respectively.

The advancement of nanotechnology has demonstrated the ability of metal-oxide-based nanofluids (NFs) to produce high heat flux in microscale thermal applications. Convective heat transfer (HTC) and flow characteristics (pressure drop (ΔP) and friction factor (f)) of aqueous ZnO NFs' within a circular mini tube (Di = 1.0 mm, L = 330 mm) were analyzed. Experiments were carried out under steady-state and varying flow rates using 0.012–0.048 wt % of NFs and sodium hexametaphosphate (SHMP) and acetylacetone (ACAC) as surfactants (SFs). Laminar flow and constant wall heat flux conditions were used to assess NFs heat transfer properties, ΔP and f. The viscosity (VC) and thermal conductivity (TC) of NFs exhibited a strong dependence on the operating temperature and NFs concentration. VC and TC increased by increasing the NFs concentration and decreased by increasing the operating temperature. Maximum VC and TC enhancement of 16.75% and 23.70% were achieved for SHMP-stabilised NFs, respectively. The average HTC increased by increasing NFs loading and flow rate, with HTCmax of 17.0% noticed for ACAC-stabilised NFs. The ΔPmax and fmax were 16.0% and 12.0%, respectively. Experimental and theoretical results showed a maximum deviation of ±7.0% and ±4.0%, respectively.

Advancements in additive manufacturing technology allows design of novel lightweight passive heat sink based on triply periodic minimum surfaces (TPMS) lattices. Topology optimization has been adopted to obtain efficient lightweight passive heat sink designs that maximize heat dissipation. However, in the topology optimization framework, the mechanical loads are usually not considered which limits its application under severe loading conditions. This paper presents a multi-objective topology optimization based on Solid Isotropic Method of Penalization (SIMP) approach that simultaneously optimize both thermal and structural objective functions to yield optimized structures with better heat dissipation and enhanced structural integrity. Three load cases are studied considering both the thermal and structural load scenarios. For each scenario, a weighted sum method is used to linearly combine the two objective functions in order to obtain the Pareto front. The obtained optimal configuration is further transformed to generate a TPMS-based structure employing a novel density mapping approach. Primitive (P), Diamond (D), Gyroid (G), and IWP TPMS structures are considered. To further study the effectiveness of mapping, the thermal performance of the mapped structures is measured using the effective thermal conductivity The mapped Primitive TPMS-based structures were found to possess superior heat conduction performance compared to other mapped TPMS structures. The unit cell mapping sensitivity along and perpendicular to heating direction was also investigated. It was found out that increasing number of unit cells in a direction perpendicular to heating direction enhanced the structure's effective conductivity. The structural integrity of the mapped heat sink structures were also examined measuring their strain energy density under both self weight loads and external structural loads.

This experimental study is focused on heat transfer performance and pressure drop characteristics of ZnO/DIW-based nanofluids (NFs) in horizontal mini tubes of different (1.0–2.0 mm) diameters. Different mass concentrations (0.012–0.048 wt %) of nanoparticles (NPs) were tested with varying fluid flow rates (12–24 ml/min) of NFs. The thermal conductivity (TC) and viscosity (VC) of stable NFs were tested at 20–60 ᵒC, at a fixed temperature (40 °C), and concentration of NPs (0.048 wt%) the maximum rise was 18.27% and 20.31%, respectively. The local and average heat transfer coefficients (HTCs) and the pressure gradient were noticed to be directly proportional to volume flow rate of NFs and the mass concentration of NPs. However, an inverse trend was noticed with the test section's diameter. At 0.048 wt % of NPs and 24.0 ml/min flow rate of NFs, the maximum rise in local and average HTCs and pressure gradient was 17.11–11.61% and 13.05–9.79%, and 29.19–12.25%, respectively, in a tube's diameter of 1.0–2.0 mm. The friction factor increased with NP's loading while the same reduced with the fluid flow rate. The corresponding maximum change in the friction factor was 28.85–12.72% for the tubes with 1.0–2.0 mm diameters, respectively, at a 12.0 ml/min flow rate of NFs. The comparison of experimental findings for the HTCs, pressure gradients and friction factors with the standard Shah and Darcy's correlations showed that the observations are in good agreement with the predicted ones.

This study numerically and experimentally investigates the forced convection heat transfer in three mathematically designed heat sinks with lattice topologies based on triply periodic minimal surfaces (TPMS). The TPMS lattices consist of periodically arranged Diamond (D) or Gyroid (G) unit cells of 10 mm size and 80% porosity, considering two TPMS topologies; solid and sheet networks. This investigation examines the thermohydraulic performance of these novel heat sinks and compares them with other heat sinks in the literature. The hydrodynamic characteristics are studied with an airflow channel, and the thermal performance is explored with a validated numerical model. The results show that form drag dominates pressure drop in the range 2000

The present investigation studies the flow and heat transfer of an engine oil-based at an angle of inclination of 45° to the horizontal. The single-phase model has been used, which means that both the nanoparticles and the base fluid are thermally balanced with no slip between their molecules. The nanofluid is comprised of Iron oxide and gold nanoparticles and the base fluid is taken as engine oil. Furthermore, both gravity and mobility of substrate eventually cause nanoparticle motion. The bvp4c MATLAB scheme is used to conduct numerical calculations and Mathematica function DSolve to find the analytical solution. Two thermal conductivity models, the modified Maxwell model for spherical particles and the Xue model for cylindrical particles are used. It is discovered that the Maxwell model of hybrid nano liquid film has a higher heat transfer rate gain than the Xue model. It is inferred from this that the performance of the hybrid-nano liquid film is far better than the common nano-liquid film. Comparison of analytical and numerical results for Nusselt number is also added.

The flow of nanofluids is of great importance because of their substantial industrial usage and alluring heat transfer capabilities. Recently, an innovative notion namely “hybrid nanofluid” has replaced the customary nanofluid flows to further enhance the heat transfer capabilities. We in this envisaged mathematical model are heading in the same direction and are intended to present a comparative analysis of the heat transfer competence of two time-dependent fluid models namely; hybrid nanofluid (Copper–Iron Oxide, Manganese- Zinc ferrite/Diathermic oil) (Cu-Fe2O4, Mn-ZnFe2O4/DO) and simple nanofluid (Mn-ZnFe2O4/DO) flows amidst two rotating disks in a porous media with Darcy-Forchheimer effect. The subject flows are assisted by the thermal stratification with nonlinear radiation effects. A blend of numerical “bvp4c” and statistical “Response Surface Method (RSM)” approaches is utilized to analyze the envisioned mathematical model. Tabulated and graphical depiction of the outcomes is given to comprehend their appraisal. It is comprehended that the radiation and thermal stratification parameters possess differing trends for the fluid temperature profile. Furthermore, it is observed that the parameter estimation and significance indicate both skin friction coefficient models are similar. The fitted model for skin friction and Nusselt number are the best fit where the normality assumption is satisfied.

Freezing desalination (FD) is an attractive water treatment process with relatively low energy consumption and simple maintenance. In this work, indirect brine crystallization experiments are conducted to investigate the salinity gradient in the formed ice by freezing brine under different conditions and evaluate the effects of these conditions on freezing time and heat transfer. These experiments demonstrate salinity gradient reaching 60% reduction in axisymmetric tray of 20 cm diameter in the first 5% formed ice. The 1st principle heat balance model is developed to predict the freezing time and heat transfer. It was validated experimentally and the discrepancies are less than 5%. Sensitivity analysis based on the develop model were conducted to assess system parameters including the brine initial temperatures, freezing source temperatures and subcooling temperatures. Results reveal that the freezing time increases linearly with initial fluid and subcooling temperatures, but decreases exponentially with cooling source temperature. Freezing source temperature plays a significant role on the freezing time. Additionally, multistage-freezing desalination procedures show that potable water can be obtained from 35 g/L solution brine after four successive freezing steps at 5% ice yield in each freezing.