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1.前言近年来随着汽车性能的提高,迫切要求热交换器实现小型、轻量、高性能化。散热器的散热量 Q 由传热系数 K、传热面积 A、壁面两侧流体的对数或算术平均温差Δt_m 来决定,用关系式表示如下:Q=KAΔt_m(1)对于汽车来说,Δt_m 值是由其它条件决定的,因此,要加大Δt_m 值是很困难的。为了增加散热量,只有增加 KA 值。从实现热交换器的轻量、小型化的观点来看,必须将 A 值尽可能地缩小,这样就只能增大 K 值。传热系数 K是根据下列公式下定义的,设空气及水侧的放热系数为α_α、α_w,传热面积为 A_α、A_w,散热
1. Introduction In recent years, with the improvement of automobile performance, it is urgent to make the heat exchanger small, lightweight and high performance. Radiator heat dissipation Q by the heat transfer coefficient K, heat transfer area A, the fluid on both sides of the logarithm of the fluid or the arithmetic mean temperature difference Δt_m to determine the relationship as follows: Q = KAΔt_m (1) For cars, Δt_m Value is determined by other conditions, therefore, to increase the value of Δt_m is very difficult. In order to increase the heat dissipation, only increase the KA value. From the viewpoint of achieving a lightweight and miniaturized heat exchanger, the A value must be reduced as much as possible so that only the K value can be increased. Heat transfer coefficient K is defined according to the following formula, set the air and water side of the heat release coefficient α_α, α_w, heat transfer area A_α, A_w, heat