Improving HEAT TRANSFER in thermal systems has become a focus of many research studies due to the critical need for efficient waste of residual HEAT. The regulation of HEAT TRANSFER between components in thermal systems has a direct impact on their efficiency and performance. As a result, effective HEAT management is critical to improving the efficiency of thermal systems and extending the life of their components. It should be noticed that baffles are important structural components widely used in various industrial applications like HEAT exchangers, solar collectors, electronic cooling, etc. In addition, baffles enhance fluid mixing and HEAT TRANSFER behaviors. Most industrial systems do not operate in a steady state. In particular, transient phases occur during start-up and shut-down or during the control phase of controlled systems. Thus, in laminar flow, baffles induce flow unsteadiness or help the flow to bifurcate from a steady state to an unsteady flow. This paper treated the effects of different baffle shapes incorporated in channels on HEAT TRANSFER rate, efficiency and friction factor in mixed and FORCED CONVECTION cases. Various experimental and numerical studies have been carried out on this topic to examine HEAT TRANSFER enhancement compared to the flow energy. It was noticed that increasing the Reynolds number, blockage ratio and decreasing the Grashof number can achieve an increase in HEAT TRANSFER. The maximum HEAT TRANSFER enhancement was obtained for higher blockage ratio and higher Reynolds number in FORCED convective flow. The highest HEAT TRANSFER improvement was obtained for the 45° angled baffles (between 150% and 850%). In mixed convective flow, the highest rate of HEAT TRANSFER was obtained for transverse baffles (2.8 times compared to a similar channel with no baffles). Finally, This comprehensive review is beneficial for researchers focused on flow and HEAT TRANSFER applications to use other baffle designs and fluids beyond air.

In his research article, several models of HEATsink were optimally designed in fin length, width and height along with pin placement which consists of 4 pin fin HEATsink models HEATsink (including square with different pin angles, circular, truncated cone, and cone pin HEATsinks and one model of the plate-fin HEATsink (PFHS)) in order to achieve better thermal performance as well as less energy consumption and were numerically investigated under high air velocity and HEAT fluxes. Different parameters such as peak temperature, Nusselt number, HEAT resistance, pressure drop, and energy consumption were compared. The results show that the square PPFHS with the pin angle of 45 degrees has the highest thermal performance compared to the rest of the models while also having the highest pressure drop and energy consumption between the models consuming more than 255 and 358 percent more energy in order to have the same air velocity in the pathway, while the truncated and the fully formed cone model despite having 25% and 30% less thermal performance, have the least pressure drop between the pin models of the HEATsinks and therefore consume the least energy out of the PPFHS.

The present paper describes a two-dimensional finite volume numerical simulation of flow and HEAT TRANSFER in airflow windows by free and FORCED CONVECTION techniques. The governing equations are the fully elliptic, Reynolds-averaged Navier-Stokes equations. The simple algorithm is employed to correct the pressure term. The second-order upwind scheme is used to discretize the CONVECTION terms. The (k-e/RNG) turbulence model is applied for the flow simulation. The mesh used is the body-fitted, multi-plane grid system. Results on the variations of velocity and temperature profiles with geometrical parameters, at different temperature and velocity, for HEAT TRANSFER by free and FORCED CONVECTION techniques are presented. Comparisons of the present results on temperature distribution for FORCED CONVECTION and for free CONVECTION with the available experimental FORCED CONVECTION data indicate that the airflow-influenced FORCED CONVECTION methods are considerably enhanced.

A theoretical solution is presented for the FORCED CONVECTION HEAT TRANSFER of a viscoelastic fluid obeying the Giesekus constitutive equation in a concentric annulus under steady state, laminar, and purely tangential flow. A relative rotational motion exists between the inner and the outer cylinders, which induces the flow. A constant temperature was set in both cylinders, in this study. The fluid properties are taken as constants and axial conduction is negligible, but the effect of viscous dissipation is included. The dimensionless temperature profile, the normalized bulk temperature, and the inner and outer Nusselt numbers are derived from solving non-dimensional energy equation as a function of all relevant non-dimensional parameters. The effects of Deborah number (De), mobility factor (a), Brinkman number (Br) and velocity ratio (b) on the normalized temperature profile and Nusselt number are investigated. The results indicate the significant effects of these parameters on the dimensionless temperature distribution and Nusselt number.