在工業程序中，化學工程師所執行的各種操作均會涉及到能量的交換，而這些能量通常以熱的形式出現，因此熱交換裝置在工業上扮演了相當重要的角色。 流體流經熱交換器的方式有同向流、逆向流及交叉流，而同向流只是課本上理論的研討，因為它效率低，所以工業界是不採用。本研究的研究對象為非穩定性交叉流熱交換器。首先利用能量不滅原理和數學模式分別對熱流、冷流及分隔板建立三個能量守恆方程式，然後再對此三個能量守恆方程式加以無因次化。我們利用有限差分法計算出不同條件下之各種例子。並且以不同的參數探討系統處於非穩態下的溫度分佈。 In industrial processes , most operations operated by a chemical engineer will involve with energy exchange . And the energy usually is performed in heat form . So the heat transfer instrument is important in industrial operations . The ways , which the fluid flow through a heat exchanger , are parallel-flow , counter-flow and crossflow . Our research is the crossflow heat exchanger in unsteady state . First , the law of the energy conservation and mathematical formulation are established by three governing equations of energy conservation for hot fluid , cold fluid , and separator sheet . Then , these three governing equations can be converted into three dimensionless equations . The finite difference method is calculated easily for the case of different conditions . Finally , we discuss the unsteady state temperature distributions with different parameter .
