火积耗散理论在平行流热管换热器性能评价中的应用

火积耗散作为传热过程可逆性判断依据,可应用于换热器优化. 分析探究了热管换热器的温差、充液率、倾角及迎面风速对火积耗散的影响,利用焓差实验室进行平行流热管换热器性能试验. 随温差增大,火积耗散增大. 随充液率增大,火积耗散先增大后减小,温差越大,火积耗散变化幅度随充液率增大而增大. 增加倾角,火积耗散比未倾斜时小. 随迎面风速增大,火积耗散减小,且减小幅度随温差增大而增大. 相同传热量,火积耗散值最小时,为系统最优工况.

On the Application of Entransy Dissipation in the Performance Evaluation ofthe Parallel-Flow Channel Heat Pipe Exchanger

Entransy dissipation is used as a invertibility judgment in the heat transfer process,which can be applied to heat exchanger optimization. In this paper,we investigates the effects of temperature difference,liquid filling rate,inclination and approach velocity of the heat pipe exchanger on entransy dissipation.The performance test of the small channel heat pipe exchanger is carried out by using the enthalpy difference laboratory. The results show that the entransy dissipation increases as the temperature difference increasing. With the increase of liquid filling rate,the entransy dissipation increases first and then decreases. The change of entransy dissipation increases with the increase of the liquid filling rate,as the temperature difference increases. The entransy dissipation is smaller with increasing inclination than without inclination. The entransy dissipation decreases with the increase of the approach velocity,and the decreasing speed increases as the increase of temperature difference. In the case of same exchanging heat quantity and the entransy dissipation is the smallest,the system works at the optimal operation.