论文部分内容阅读
通过实验和数值方法研究了水平圆柱蓄热单元蓄、放热过程中换热特性的共性和差异,分析了壁面温度在高于/低于相变温度10 K的间隙性周期热边界条件下,蓄放热单元的热动态特性。结果表明,在相变起始阶段,蓄、放热过程主要以导热换热方式为主;随着蓄放热过程的进行,蓄热过程的换热方式转变为以自然对流主导,放热过程则仍以导热主导。在本文所研究的等温差等时长的间歇交替蓄-放热循环中,由于蓄热融化速率大于放热凝固速率,会出现由不稳定状态发展到周期稳定状态的演变过程;在周期稳定工况下,蓄放热单元会在完全液相到液固两相共存间交替变化。
The commonalities and differences of heat transfer characteristics of horizontal cylindrical thermal storage units during storage and exothermic process were studied by means of experiments and numerical methods. Under the intermittent thermal boundary conditions with wall temperatures above and below the phase transition temperature of 10 K, Storing the thermal dynamic characteristics of the thermal unit. The results show that during the initial stage of phase transformation, the heat storage and exothermic processes are mainly dominated by the heat transfer and heat transfer modes. With the progress of the heat and storage process, the heat transfer mode of the regenerative process is changed to dominate the natural convection and the exothermic process It is still dominated by thermal conductivity. In the intermittent alternate heat storage and exothermic cycle with equal isothermal temperature difference studied in this paper, the evolution from unstable state to periodic steady state occurs because the heat storage and thawing rate is greater than the exothermic solidification rate. Under the storage and discharge unit will be in full liquid to liquid-solid two-phase alternating between changes.