发动机舱的冷却气流仿真与散热的改善

Cooling Airflow Simulation and Heat Dissipation Improvement of Engine Compartment

为降低冷却阻力,对原车机舱气流进行了数值仿真,基于仿真结果,从改变冷却气流方向、降低气流经过前端部件的能量损失和提高散热器性能3个角度提出了不同的方案,进行风洞试验验证,结果表明,加装前端隔板后散热器进气量增加15%,而冷却阻力降低5 counts。对于机舱内部散热问题,通过仿真与试验结合的方法,采取多种措施(如在方向机后加装挡板引导气流加强其局部流动,风扇后加装导风罩进行热气流疏导,发动机进气口加装导流装置,以提供额外的冷却气流),结果方向机变速器悬置的散热得到改善,而前端的冷却气流不受影响。

In order to reduce cooling drag,a numerical simulation on the air flow of original engine compartment is conducted.Based on the results of simulation,different improvement schemes are proposed from three aspects:changing the flow direction of cooling air,reducing the energy loss of air flow passing through front-end components and enhancing radiator performance,on which wind tunnel tests are carried out for verification.The results show that after front-end plate separator is added the flow rate of intake air increases by 15%,and cooling drag lowers by 5 counts.As for the heat dissipation within engine compartment,by combining simulation and test,several measures are taken,such as adding baffle plate behind steering box to intensify the local air flow,adding flow guiding shroud behind fan for guiding hot airflow and adding flow guiding device at the intake port of engine to supply extra cooling air flow.As a result,the heat dissipation of steering box and transmission mounts are improved with the cooling air flow in front-end unaffected.