弓形截面柱状相变储热装置热性能数值模拟

Numerical study on thermal performance of cylindrical phase change heat storage device with bow section

为提升传统卧式柱状相变储热装置性能,结合相变材料(PCM)熔化过程传热特性,设计了一种弓形截面水平管壳式相变储热装置。建立了弓形截面和传统圆形截面柱状相变储热单元模型,通过模拟研究对比了不同温度条件下2种装置的蓄/放热过程。结果表明:在储热温度为80℃时,弓形截面相变储热单元的储热时间较圆形截面储热单元减少48.37%,放热时间基本无变化;在换热流体温度在60~80℃变化时,随着储热温差增大,弓形截面相变储热单元内PCM熔化时间相比传统圆形截面相变储热单元减少由43.85%增至48.37%。此外,相比添加翅片、多层套管等改进方式,弓形截面柱状相变储热装置结构简单、造价低廉。研究结果可为相变储热装置性能优化提供参考。

To improve the heat transfer performance of conventional horizontal cylindrical phase change heat storage device, combining with the heat transfer characteristics of phase change material(PCM) melting process, a cylindrical phase change heat storage device with bow section was proposed. By establishing the models for the cylindrical phase change heat storage device with bow section and conventional circular section, the heat storage and release process of the two devices at different temperatures was numerically investigated. The results show that,when the storage temperature is 80 ℃, the heat storage time of the phase change heat storage unit with bow section is 48.37% shorter than that of the one with circular section, and the heat release time almost has no change. When the temperature of heat exchange fluid changes from 60 ℃ to 80 ℃, compared with the phase change heat storage unit with circular section, the melting time reduction of PCM in the phase change heat storage unit with bow section increases from 43.85% to 48.37%. In addition, compared with the improved methods such as adding fins and multilayer casing, the bow section cylindrical phase change heat storage device has simpler structure and lower cost. The research results can provide a reference for performance optimization of phase change heat storage devices.