管式换热器的优化设计

针对管式换热器设计过程中几何关系的多自变量约束难题，提出了以管长、折流板间距与壳外径之比、管间距与管外径之比三个设计变量作为优化判据。将初投资额与年运转费用作为寻优目标函数，采用复合形电算法求解，避免了求导数复杂的数学运算。实例优化计算结果与常规计算结果的比较表明，优化设计可使管式换热器在满足给定约束条件下，节约２５ ％ 以上换热面积，提高管程和壳程的流速，从而提高传热系数，最终得到操作、能耗和投资等方面的最佳经济结构。

Optimization of pipe heat exchanger

In the light of the problem of multiple variables restrain in the design of pipe heat exchanger, it is proposed taking three variables, the pipe length, ratio between the table flap space and the shell outer diameter, and ratio between the pipe space and the pipe outer diameter, as optimization criterion. By taking the early investment and annual running charge as objective function for optimum seeking, and by means of computers, complicated calculation is avoided. The values obtained from the optimum calculation are compared with that from the conventional calculation, and the result shows that, by means of the optimum design, under the given restrains, the pipe heat exchanger can operate well with a reduction of over 25% heat transfer area.