关于换热器两侧换热表面最佳匹配的讨论

A Discussion on the Optimal Matching between the Surface Areas of the Two Sides of a Heat Exchanger

在分析换热器的传热方程和投资费用方程特性的基础上推导出两侧换热表面的最佳配比关系式，即两侧换热表面之比与换热性能比和投资费用比乘积的平方根成反比，进而在投资费用给定的条件下对传热方程求极并导出该关系式，从而证实分析的正确性．算例表明，凡满足最佳配比关系的换热器表面，其单位传热量的投资费用最省．为换热器优化设计和检验提供了理论依据．

Based on the results concerning an analysis on the equations of heat transfer and investment cost, the optimal matching between heat exchanger surface areas is further discussed. With a simple heat exchanger as an example, a quantitative analysis has been made. It is proved that the ratio between the two surface areas is inversely proportional to the root of the product of the ratio between the heat transfer coefficients and the ratio beteen the surface investment unit prices. This can be referred to as the optimal matching rule or the sequence root rule. Obviously, when the investment cost is taken into consideration, the optimal matching is not an equivalent one. It is the authors view that this is a challenge to the conventional viewpoint of equivalent matching of thermal resistances on the two sides of the heat exchanger.