热漏对换热器(火积)耗散最小化的影响

建立了存在热漏的换热器的传热过程模型.假定热流体与冷流体间的传热以及冷流体与外界环境间的热漏均服从牛顿传热定律,在冷流体净传热量一定的条件下,应用最优控制理论导出了换热过程(火积)耗散最小时热流体温度和冷流体温度的最优构型,并将最优路径分别与热流体温度一定和热流率一定的传统传热策略进行了比较.研究结果对于实际换热器的优化设计和最优运行具有一定的理论指导意义.

Influence of heat leakage on entransy dissipation minimization of heat exchanger

Model of a heat transfer process in heat exchanger with heat leakage is established in this paper. Both the heat flux between the hot and cold fluids and the heat leakage between the cold fluid and outside environment are assumed to obey Newtonian heat transfer law. On condition that the net amount of heat transferred by the cold fluid is given, the optimal temperature configurations of the hot and cold fluids for the minimum entransy dissipation of the heat transfer process are derived by using the optimal control theory. Optimal paths are also compared with the conventional strategies of heat transfer under constant hot fluid temperature and constant heat flux rate operation. The results obtained in this paper could provide some theoretical guidelines for the optimal design and operation of real heat exchangers.