不同海拔对车用散热器性能的影响分析

为了研究不同海拔对车用散热器性能的影响,采用Fluent软件建立车用散热器仿真模型.由于散热器结构复杂,直接建模仿真计算量较大,将散热器翅片部分视作多孔介质模型,多孔介质参数通过对散热器单元仿真得到.结果表明:空气密度的下降是影响散热器传热性能的主要原因,随着海拔的升高,大气压力逐渐降低,空气密度随之减小,导致气体雷诺数相应减小,同时对流换热系数和散热量呈现下降趋势.海拔每升高1000 m,换热系数下降4.72％,散热量下降6.58％.

Effects of Different Altitude on the Performance of Vehicle Radiator

In order to study the influence of different altitude on the performance of vehicle radiator, the simulation model of vehicle radiator was established using FLUENT software. Because of the complexity of radiator structure, the amount of direct modeling and simulation was large. The fins of radiator were regarded as porous media model. The parameters of porous media were obtained by the simulation of radiator unit. The results show that the decrease of air density is the main reason that affects the heat transfer performance of radiator. With the increased of altitude, the atmospheric pressure decreased and the air density decreased, which led to the decrease of Reynolds number and the decrease of convective heat transfer coefficient and heat dissipation at the same time. With every 1000 m rising in altitude, the heat transfer coefficients declined by 4.72%, the heat dissipation decreased by 6.58%.