换热网络优化影响因素分析及局部最优解的跳出策略

在换热网络分级超结构的基础上提出了换热网络优化数学模型,对其用惩罚函数法去约束后通过算例分析其非线性,明确了优化起始点冷热流体的匹配方式以及换热器的面积是影响求解效果与效率的两个关键因素.同时提出了一种基于蒙特卡罗法结合多起点面积法的局部最优解跳出策略,并用算例验证表明,该策略能有效地跳出局部最优解,得到全局最优解.

Analysis on Influencial Factors in Heat Exchanger Network Optimization and the Strategy for Jumping out of Local Optimal Solution

A mathematical model for heat exchanger network optimization was established based on the stage wise superstructure.By analyzing the serious nonlinearity of the model,it is shown that two key factors ,namely,the matching mode and the exchanger area,have a strong impact on calculation efficiency and accuracy.Moreover,the heat exchanger network optimization problem belongs to the mixed integer non-linear programming problem,so,it is easy to fall into the local solution in optimization process.In order to relieve this limitation in the synthesis of heat exchanger networks,a novel approach which combines initial multi-point method with Monte Carlo method was presented.Effectively jumping out of the local solution to obtain global optimal solution by using this approach was validated by numerical examples.