Simulation Research Of Heat Dispersion Of Vehicle Underhood

The research object was a vehicle model which provided by the company in this paper,and it was used to research on air flow and heat dissipation performance in Underhood. Theresearch used the theory of fluid mechanics and heat transfer and the numerical simulationmethod.First, the model was simplified on the basis of guarantee the calculation accuracy, highquality grid was gained based on grid generation software Hypermesh and Tgrid. In anambient temperature of30°C, using FLUENT analyzed the thermal performance of theoriginal vehicle model which the speed was80km/h. Fan surface pressure was processed withUDF, three-dimensional velocity vector diagram and the temperature distribution of the cabinwas obtained by post-processing, the result showed the prototype had the problems which wasair leakage、hot air reflow phenomenon and the vortex;Second, the based on the improvement of the diversion and choke and based on theimprovement of the vortex were put forward on the problems. The result showed the based onthe improvement of the diversion and choke added a wind deflector to increase the amount ofcooling air flow through the radiator group, it made the temperature to decrease3.3K、improved the efficiency of the heat dissipation, and effectively prevented the hot gasbackflow; the based on the improvement of the vortex added the guide plate weakened theeffect of the vortex to the flow condition of the air intake grille flow of cooling air, andincreased the cooling air flow rate and mass flow rate into the radiator group, it made thetemperature to decrease1.1K, further increased the cooling efficiency;At last, the demand of radiator cooling air which was under the rated power wascalculated by empirical formula, and compared with the simulation results, it was concludedthat the cooling effect of the based on the improvement of the vortex improved models wasbetter, the error was around3.5%between the amount of cooling air flows into the radiatorand the calculated value, meeting the requirements of Heat dispersion. The research resultsshowed that the improved scheme can provide reference for the research of automobile cabinthermal management, and could guide the design and development of vehicle.