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采用CFD方法数值模拟了小型汽车发动机冷却系统对全车阻力的影响特性。汽车的内部及外部(发动机舱及舱内)均设置了数值模拟网格。分别计算了散热器及风扇对阻力的影响,采用本校实验结果(散热器压力损失)及制造商提供的数据(散热器及风扇的质量流率)确定初始及边界条件,为基于RNS的CFD提供输入。对汽车轮胎运动模式及行驶速度对散热系统阻力及汽车总阻的影响特性也进行了计算分析。预测结果表明,冷却系统阻力占汽车总阻的6.9%,与实测值吻合。
The CFD method is used to numerically simulate the impact of the cooling system of small car engine on the whole vehicle resistance. The interior and exterior of the car (engine compartment and cabin) are equipped with numerical simulation grid. The influence of the radiator and the fan on the resistance is calculated respectively. The initial and boundary conditions are determined according to the results of our university (the pressure loss of the radiator) and the data provided by the manufacturer (the mass flow rate of the radiator and the fan), and provide the RNS-based CFD enter. The calculation and analysis of the influence of the vehicle tire movement mode and driving speed on the cooling system resistance and the total vehicle resistance are also carried out. The prediction results show that the cooling system resistance accounts for 6.9% of the total resistance of the car, which is in good agreement with the measured value.