In the this study , numerical analysis of heat transfer in the radiation system of the car has been investigated by using pure water and water with nano-fluid. ANSYS fluent version 16.1 has been conducted to carry out the simulation process using Computational Fluid Dynamic (FCD) approach. This study has been validated with experimental results and based on the simulation results the error was 8% when applying the same boundary condition. And the validation process was carried out for the flow rate with Nusselt number in both concertation 0.7 % and 1 %. Based on numerical analysis, the Nusselt number has been increased by increasing nano particle concertation. Increased number of Nusselt causes the enactment of the heat exchanger. The previous experimental data show that the heat transfer of the nanofluids was based highly on the concentration of nano particles, the flux conditions and the weak temperature-dependent heat transfer conditions.

Numerical modeling analysis of mixed convection heat transfer for air flow in a cavity with bottom local heat source and top inlet and outlet sections is studied. Also, the cavity equipped by vertical triangular obstacle on the top wall in order to enhancement the convection inside the cavity are researched. System of dimensionless stationary Navier-Stokes equations is solved numerically by discretizing the compositional domain into small grids. Mixed convection regimes are the viscous incompressible Newtonian fluid with Reynolds number range (800-1400) and the Grashof number ranged (105-108) and at fixed Prandtl number at (7.1). The pressure, temperature and velocity distributions characterizing the basic laws of viewed process. The results showed that the main circulating currents in different zones of the cavity is due to the effect of number of blocks and the presence vertical triangular obstacle on the top boundary of the cavity. The formation of thermal conditions in the region under study and the effect of low temperatures above the heated bottom wall on the circulation fluid flow in a cavity. Distribution pattern established velocity and temperature profile in centered sections depending on the height of vertical triangular obstacle. Also, the results showed that the Nusselt number increased by about 26% when increasing the height ratio of triangular obstacle to (h/H=0.5) with three blocks.