Study On The Simulation Of Heat Transfer Performance For Automotive Radiator Based On CFD

Modern vehicle require a optimized thermal management system to minimize fuel consumption, and customer wishes for higher powered engines as well as for more safety and comfort result in more tightly packed engine compartments. All these items may lead to rising heat load for cooling package. And heat exchangers module is one of the most important subsystems of thermal management system. Because of the configuration of heat exchangers, cooling air passage and complex vehicle driving conditions and environments, the mismatching of heat exchangers in vehicle usually results in many problems. To reduce the development time and to solve the matching problem of heat exchangers module for vehicle cooling system, both experimental and numerical study of fluid flow and heat transfer in the heat exchangers module are conducted in this present thesis. The main contents of this dissertation are:Firstly, in-depth research of the effects of heat transfer and pressure loss of cooling based on test parameters on bench is very important for heat exchangers performance evaluation.Secondly,, this research applies CFD (Computational Fluid Dynamics) and NHT (Numerical Heat Transfer) method to simulate the fluid flow and heat transfer in the heat exchanger and/or heat exchangers module. The core of heat exchanger is simplified with porous media model, on the basis of the porous media and distributed resistance model, the governing equations in the three-dimensional coordinates for incompressible turbulent fluid flow and heat transfer of the heat exchangers are derived. The 3D simplified geometric models of heat exchanger are established.This research discretizes the computing field by structured and unstructured grid generation technique. The computational scheme is based on a finite volume discretization with SIMPLEC pressure correction. A point implicit Gauss-Seidel iterative method is used in conjunction with an algebraic multigrid (AMG) method to solve the algebraic equations. Then applying data visualization technique to post-process the calculation results. The flow distribution, pressure field and velocity field are used to predict the detailed performance and to show ways to develop suitable remedies in the concept phase of the heat exchanger module development. In this research, the calculated examples are cooling air flow distribution in the side-by-side heat exchangers, and the effect of inlet-outlet-tube position on heat exchanger performance. The simulation results can provide some insight and experience for heat exchanger design engineers, and the virtual shape optimization of heat exchanger need to be studied in the near future.Finally,The key factor which most influences heat transfer coefficient and air flow friction coefficient is the Computational Fluid Dynamics.The predicted data for heat load is basically in agreement with experimental data under the same operating condition. The simulation results show that the angle of louver of fins significantly influences turbulence and the heat transfer coefficient.Finally when the angle of louver ranges between 20°and 30°,an optimum is proposed to improve heat transfer performance. The simulation got the optimum value of the heat transfer coefficient as the angle of louver ranges 20°to 30°.