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A numerical study is presented for forced convection of an incompressible oscillating flow in a two-dimensional channel at constant wall temperature using the lattice Boltzmann method. The oscillatory motion of the fluid in the channel is driven by a periodic pressure gradient. The model adopted in this study is the coupled lattice Bhatnagar-Gross-Krook model. Pressure boundary condition is used in the inlet and outlet boundaries, and extrapolation scheme is used in the solid boundaries. The dependence of the flow and heat transfer characteristics on different Womersley numbers and the amplitudes of the pressure gradient are presented. Results are consistent with those from previous numerical simulations and theoretical analyses.

The main goal of the present study is to investigate the heat transfer enhancement in a channel partially filled with an anisotropic porous block (Porous Foam) using the lattice Boltzmann method (LBM). Combined pore level simulation of flow and heat transfer is performed for a 2D channel which is partially filled with square obstacles in both ordered and random arrangements by LBM which is not studied completely in the literature. The effect of the Reynolds number, different arrangements of obstacles, blockage ratio and porosity on the velocity and temperature profiles inside the porous region are studied. The local and averaged Nusselt numbers on the channel walls along with the respective confidence interval and comparison between results of regular and random arrangements are presented for the first time. For constant porosity and block size, the maximum value of averaged Nusselt number in the porous block is obtained in the case of random arrangement of obstacles. Also, by decreasing the porosity, the value of averaged Nusselt number is increased. Heat transfer to the working fluids increases significantly by increasing the blockage ratio. Several blockage ratios with different arrangements are checked to obtain a correlation for the Nusselt number.

In this paper, forced convection of a turbulent flow of pure water, Al₂O₃/water nanofluid and Al₂O₃–Cu/water hybrid nanofluid (a new advanced nanofluid composited of Cu and Al₂O₃ nanoparticles) through a uniform heated circular tube is numerically analyzed. This paper examines the effects of these three fluids as the working fluids, a wide range of Reynolds number (10 000 ≤ Re ≤ 10 0000) and also the volume concentration (0% ≤ ϕ ≤ 2%) on heat transfer and hydrodynamic performance. The finite volume discretization method is employed to solve the set of the governing equations. The results indicate that employing hybrid nanofluid improves the heat transfer rate with respect to pure water and nanofluid, yet it reveals an adverse effect on friction factor and appears severely outweighed by pressure drop penalty. However, the average increase of the average Nusselt number (when compared to pure water) in Al₂O₃–Cu/water hybrid nanofluid is 32.07% and the amount for the average increase of friction factor would be 13.76%.

The aim of this paper is investigating the forced convection heat transfer in a channel with transverse rectangular cavities using the lattice Boltzmann method (LBM) which is not available in the literature yet. The effects of the Reynolds number (100–400), cavity aspect ratio ($\mathrm{\text{AR}}=0.25$, 0.5, 1.0), distance of cavities from each other ($S^{\prime }=0,2,4,6$) in fixed depth of cavity ($A^{\prime }=0.5$) on the velocity and temperature profiles are studied. Moreover, the flow patterns such as deflection and re-circulation zone inside the cavities are obtained. The local and averaged Nusselt numbers on the channel walls are achieved. The results show that the channel with cavities achieves heat transfer enhancements relative to the smooth channel. For the constant cavity aspect ratio, the maximum value of averaged Nusselt number in the channel is obtained in the case of $S^{\prime }=2$. Heat transfer to the working fluids increases significantly by increasing the aspect ratio. The existed results are used to ascertain the validity of the numerical code and excellent agreement between results was found.

Recently, various ways are investigated to augment heat transfer in different applications such as porous ceramic domain. Adding nanoparticles to fluid is the best operational way to increase the conduction of fluids. In this paper, migration of nanofluid inside a porous duct under the impact of magnetic force is scrutinized. LBM is applied to present comprehensive parametric analysis for various concentrations of nanofluid, Hartmann, Reynolds, and Darcy numbers. Outputs illustrate that Nu augments with improve of Lorentz forces. Augmenting Da significantly enhances the convective flow in our model.

The current study deals with the numerical investigation of the substrate board characteristics using different materials (FR₄, silicon cladding and copper cladding) on which nine nonidentical electronic components (ECs) are mounted, which are supplied with nonuniform heat flux. The study is conducted for natural and forced convection (3m/s and 5m/s) modes of heat transfer. It is observed that for 5m/s the temperature of the ECs is dropped by 30–47^∘C using copper cladding board in comparison to FR₄ and silicon cladding board. It is also noted that with the use of copper cladding board the velocity of air required for cooling the ECs is substantially reduced by 2m/s and the temperature of the IC chip is reduced by 1.50–11.12^∘C.

In this paper, the forced convection heat transfer of Ag–MgO/water hybrid micropolar nanofluid in a channel is studied numerically which the top wall of channel is smooth and bottom of it is in stairway form. The lattice Boltzmann method (LBM) is used for solving the fluid flow and heat transfer equations. The effects of Reynolds numbers ($Re=100$–400), volume fraction of nanofluid ($\varphi =0$, 0.01 and 0.02) and stairway aspect ratio ($a∕H=0.1$, 0.2 and 0.3) on the velocity, temperature and local and average Nusselt number profiles are investigated. The results show that by incrementing the Reynolds number and solid volume fraction and decreasing the $a$/$H$ simultaneously, the average Nusselt number increases.

To decrease the exergy drop, a new style of tape with an inset of the obstacle has been applied in the current utilized heat exchanger. Numerical technique was chosen to discover the solution of the equations for the current application. Hybrid nanopowders were added into a base fluid and an experimental formulation was utilized for involving the new working fluid. Addition of nanopowder and insertion of obstacle over the tape lead to augmentation of productivity of unit and help the system to minimize the irreversibility. Checking the correctness of the procedure in the modeling has been tested and proved to be in nice agreement. Two configurations for geometry of tube have been compared in two levels of Re. The regime of fluid is turbulent and the generation of grid has been done with considering the limitation of $Y^{+}$. With the insertion of obstacle in the lowest level of Re, the swirl flow increases and $S_{\mathrm{\text{gen}},f}$ augments about 252.6% while $S_{\mathrm{\text{gen}},h}$ reduces about 21.22%. The value of heating term is much higher than the friction term, so Xd declines by 21.21%. With the use of new configuration of turbulator, elevating $V_{\mathrm{\text{in}}}$ leads to elevation of $S_{\mathrm{\text{gen}},f}$ by 24.21% but $S_{\mathrm{\text{gen}},h}$ declines about 83.39%. Adding the turbulator with obstacle, $T_w$ decreases about 0.22% when Re $=$ 2e4.

The present investigation set out to assess the influence of the surface roughness on the flow and thermal mean quantities, around the heated corrugated cylinder in the laminar steady flow. The current investigation has been devoted to a numerical analysis of a two-dimensional steady flow and forced convection heat transfer characteristics over a heated longitudinal sinusoidal shape grooved cylinder, immersed in an unconfined Newtonian fluid. The number of the grooved cavities was chosen to be 10, 20 and 30 grooves, equally distributed around the cylinder circumference with wavelength and wave amplitude of 1/50 and 1, respectively. Moreover, the thermal boundary condition effect has been analyzed by imposing a uniform heat flux and constant temperature on the cylinder periphery as a thermal boundary condition, over a Reynolds number range of ($0.1\le \mathrm{\text{Re}}\le 40$) and a fixed Prandtl number of 0.715. The numerical procedure is based on the finite volume method. The findings indicate that with increasing groove number, the total drag coefficient of the grooved cylinder reduces markedly compared to the smooth one. This trend is more pronounced as the Reynolds number increases. The effect of the groove number on the pressure coefficients is limited, where the profiles of the grooved cylinder coincide with that of the smooth one over the Reynolds number range. When the Reynolds number varies from 0.1 to 40, the average Nusselt number enhances noticeably by about 86% for the smooth and grooved cylinders. Moreover, the groove number affects significantly the average Nusselt number, where the increased groove number results in a gradual reduction in the average Nusselt number. This attenuation is more pronounced as the Reynolds number increases. To predict the average Nusselt number, a correlation has been proposed.

In this paper, the flat-plate solar collector with different porosities is considered. The use of perforated absorbers has many advantages, including the diffusion of the absorbed radiation over the entire depth of the absorber, which increases the area of heat transfer and reduces the local flux density on absorbent surfaces. A parametric study based on numerical simulation is carried out by varying the absorber plate perforation diameter and fixing its spacing. The inlet mass flow rate is changed in a large interval in order to determine the optimal operating points. The heat diffusion and energy balance equations are formulated to be suitable to analyze the influence of the absorber plates’ perforation on the GTC thermal performance. That is why, the necessary basic assumptions are developed to simulate the heat exchange mechanism as accurate as possible. Therefore, the heated air thermal conductivity is neglected against that of the absorber which allows that constant surface heat flux condition to be applied at its outer well as well as at glazing cover. The methodology of simulation is completed by aided flowchart to handle the radiation loss and pressure drops’ validation.

A hydro-dynamic thermal fully developed forced convective heat transfer analysis of magneto-hydrodynamics fluid flow through an annular sector duct is presented in this paper. Two types of thermal boundary conditions i.e., axially uniform heat flux along with peripherally uniform temperature (known as H1-condition) and, axially and peripherally uniform temperature (known as T condition), have been considered to carry out the thermal analysis of fluid. The velocity components along r and $\theta$ direction are transformed into algebraic form by using power law discretized scheme, whereas cross-sectional pressure $P(r,\theta )$ is estimated with the help of well know technique $SIMPLER$. The governing partial differential equations are solved by numerically with the help of $MATLAB$ code. Furthermore, simulated results have been compared with the existing results of literature to validate the results. From the results, it is noted that hydro-dynamically and thermally impacts relate directly by increasing the Hartman number, (M). It is further reported that the effect of magnetic field becomes insignificant for the higher number of fins, N. The findings of the present analysis will be applicable in various types of thermal systems.

Hot impinging air jets are usually used to increase heat and mass transfer. The dehydration of materials is a procedure of common significance in the chemical processes, forensic science and food industries; in the fabrication of paper, plastics and textiles as well. Effective drying of thin ink films is becoming progressively significant in the quickly development printing, packaging and coating industries. In order to minimize capital and operating cost, variables need to be optimized. For both researchers and commercial dryers, an optimization of the nozzles under striking air jets is offered for ink drying. To supply information to industrial users, a comprehensive literature review was presented to the research. An outline of the previous work of impinging air jets is also given.

An analytical model is presented that predicts the average heat transfer rate for forced convection, air cooled, plate fin heat sinks for use in the design and selection of heat sinks for electronics applications. Using a composite solution based on the limiting cases of fully-developed and developing flow between isothermal parallel plates, the average Nusselt number can be calculated as a function of the heat sink geometry and fluid velocity. The resulting model is applicable for the full range of Reynolds number, , and accurately predicts the experimental results to within an RMS difference of 2.1%.

In the present work, forced convection heat transfer was investigated numerically for the fully developed fluid flow of incompressible viscous laminar flow under the constant wall heat flux in sudden expansion channels. Various fluids were used with different concentration of nanoparticle such as Al₂O₃, TiO₂, ZnO, CuO, SiO₂. These nanoparticles were dispersed with the range of 0.5–2% volume concentrations in pure water to form stable suspensions of nanofluids. The flow assumed to be uniform in the channel inlet and numerical computations were performed for the fully developed laminar flow conditions. Ansys Fluent 16.1 code, based on finite volume approach was used to calculate the governing continuity, momentum and energy equations. Effect of the Re numbers (100$\le$Re$\le$500), nanoparticle volume concentration (0.5%$\le \phi \le$2.0%) and nanofluid type on the flow and heat transfer characteristics such as convective heat transfer coefficient, Nu number, friction factor and pressure drop has been investigated. Al₂O₃/water nanofluid was found better when compared the other references working fluids by means of heat transfer enhancement.

A brief review of convection heat transfer in thermodynamically compatible fluids of grade three is presented. Some recent results for (i) the natural convection of such a fluid between two infinitely long cylinders, and (li) the effect of variable viscosity in the forced convection of a third grade fluid in a pipe are presented.

In this paper, an actively directed microfluidic cooling approach is introduced for thermal management of high power devices. The microfluidic cooler contains flow channels and an array of micron-scale impingement jets. The coolant can be actively delivered through the jets array and guided directly to the base of the heat source, significantly decreasing thermal resistance and increasing heat transfer coefficient. Finite element method has been used to investigate the effect of cooler module. Simulation results show that a 20W heat dissipation device with 2×2 mm² in size can be kept at 127°C by 20mL/min pumping rate. The average effective heat transfer coefficient with respect to a 20°C coolant temperature is around 13 W/cm² K. The actively directed microfluidic cooler is applicable to most of the current high power devices, such as GaN/SiC and GaN/Diamond power amplifiers. The approach is capable of managing die-level heat fluxes >1 kW/cm² very efficiently, enabling a die to operate at up to 2 times the power level as compared to the conventionally microfluidic cooled die for the same working temperature. Experiments verification of this high performance cooling system is currently underway at NEDI.