多股流换热器动态过程场协同分析

建立了多股流板翅式换热器动态数学模型,通过换热器入口温度及流量阶跃的改变,模拟过渡过程中温度场的动态响应,利用温差场均匀性因子对多股流换热器过渡过程动态特性进行了评价,通过分析内部温度场与速度场的协同关系,揭示温差场在动态过程中的变化特征.将温差场均匀性因子与过渡时间结合,建立了自组织能力系数,并对多股流换热器控制品质进行了分析.多股流换热器在流量阶跃时,温差场均匀性因子平缓迁移,而温度阶跃时变化剧烈且存有极值.多股流换热器自组织系数越大,越易达到新的热平衡.

Field Synergy Analysis of the Dynamic Process of a Multi-stream Heat Exchanger

The authors have established a dynamic mathematical model for a multi-stream plate-fin type heat exchanger.Through a step change of the heat exchanger inlet temperature and flow rate,simulated was the dynamic response of the temperature field in a transient process.By using a temperature difference field uniformity factor,evaluated were the dynamic characteristics of the transient process of the heat exchanger.Through an analysis of the synergy relationship between the inner temperature field and the speed one,the variation characteristics of the temperature difference field in the dynamic process were revealed.By combining the uniformity factor of the temperature field with the transition time,a self-organization ability coefficient was established,and the control quality of the heat exchanger,analyzed.When the heat exchanger undergoes a step change of flow rates,the temperature difference field uniformity factor will smoothly migrate.In the meantime,when the heat exchanger is subjected to a drastic step change of temperature and there exist extreme values,the bigger the self-organization coefficient of the heat exchanger,the easier the attainment of a new heat balance.