This paper presents a numerical investigation of mixed convection heat transfer around a pair of identical circular cylinders placed in side-by-side arrangement inside a square cavity of single inlet and outlet ports. The investigation provided the analysis of gradual effect of aiding thermal buoyancy on upward flow around cylinders and its effect on heat transfer rate. For that purpose, the governing equations involving continuity, momentum and energy are solved using the commercial code ANSYS-CFX. The distance between cylinders is fixed with half-length of cavity. The simulation is assumed to be in laminar, steady, incompressible flow within range of following conditions: Re = 1 to 40, Ri = 0 to 1 at Pr = 0.71. The main obtained results are shown in the form of streamline and isotherm contours in order to interpret the physical phenomena of flow and heat transfer. The average Nusselt number is also computed and presented. It was found that increase in Reynolds number and/or Richardson number increases the heat transfer. Also, aiding thermal buoyancy creates new form of counter-rotating zones between cylinders.

In rocket engine nozzle design, flow separation is essential and, given the high temperatures and pressures in the thrust chamber, regenerative cooling is critical for maintaining the nozzle wall's integrity. This passage provides a summary of an in-depth numerical analysis of boundary layer separation and heat transfer within a 30°-15° cooled nozzle. The performance of the SST-V turbulence model under these conditions is assessed numerically. A variety of factors are investigated, including wall temperature, turbulent Prandtl number, and constant specific heat ratios (spanning 1.31 to 1.4 for constant fluid properties of N2O, CH4, Cl2, and air). Furthermore, variable specific heat ratios (from 1.39 to 1.66 for variable fluid properties of air, CH4, O2, and Helium) are examined, along with other parameters that affect the location of separated flow and the local wall heat transfer.

The present work displays an extensive numerical analysis for the thermo-hydrodynamic (THD) behavior in finite length journal bearings lubricated with different types of nano-lubricants considering cavitation effect. The effects of nanoparticle concentrations, cavitation and temperature rise on the performance parameters of such bearings have been explored. The bearing is simulated using Computational Fluid Dynamic (CFD) approach. The effect of using different types of nano-lubricants with different volume fractions of TiO2 and Al2O3 nanoparticles dispersed in Veedol Avalon ISO Viscosity grade 46 oil has been demonstrated. Modified Krieger-Dougherty equation has been implemented with the thermal viscosity model to to evaluate the oil effective viscosity. The obtained results show that concerning the TiO2 nanoparticles results in a higher oil film pressure and load carrying capacity in comparison with Al2O3. The bearing equilibrium position was obtained by using Response Surface analysis (RSA) with optimal space-filling design technique. The numerical model was validated by comparing the results obtained in the present work with that obtained by Feron et al. The results were found to be in a good confirmation. The attained results show that the maximum pressure grows by 21% when the bearing is lubricated with nano-lubricant.