翅片管强化方腔蓄冰性能的数值研究

Numerical study on enhancement of ice storage performance in rectangular tank by finned tube

为了研究管外耦合纵向翅片对制冷管蓄冰性能的强化作用,基于enthalpy-porosity方法建立了考虑自然对流条件下矩形腔内耦合纵向翅片的制冷管外蓄冰过程非稳态模型,并进行了数值求解.探讨了自然对流对蓄冰过程的作用机理,明确了翅片管的强化作用,分析了翅片材质及结构参数对蓄冰强化作用的影响.研究表明,受到自然对流的影响,矩形腔内的主流区域出现新的对流涡,液相区出现流动反转现象.冷媒温度-10℃、初始温度4℃条件下,相同蓄冰时间内,在制冷管的外表面上耦合纵向翅片可以在制冷光管的基础上将蓄冰量提升88.3%~260.1%.随着翅片高度和翅片数量的增加,得益于传热面积的增大,蓄冰量呈现近似线性增加.此外,翅片厚度的增加对蓄冰量的增益小于翅片高度与翅片数量增加的影响.

To study the ice storage performance of cooling tube enhanced by axially arranged external fins,a transit numerical model considering natural convection is developed based on the enthalpy-porosity method.The dynamic behavior of water solidifying outside the cooling tube in a rectangular ice storage tank is numerically studied.The underlying mechanism of natural convection effects on ice storage performance is studied.The enhancing effects of adding fins on cooling tubes are clarified and the influences of major fin parameters including fin materials and fin structures are discussed.The results indicate that,vortexes are developed in the main region of water under the effect of natural convection which leads to inversed flow pattern eventually.Under the condition of-10℃chilled water and 4℃initial temperature,the amount of ice storage can be increased up to 83.3%to 260.1%during the same period of cooling time by coupling the axially arranged external fins onto the tube compared with the smooth tube.In addition,the ice storage capacity almost increases linearly with the increase of the fin height and fin number,which benefits from the increment of the heat transfer area.In addition,increasing the thickness of the fins is less beneficial for the ice storage capacity than increasing the fin height and fin number.