封装方式对相变水箱蓄放热性能影响模拟分析

A simulation analysis on the effect of encapsulation mode on the heat storage and release performance of phase change water tank

为探究不同形状封装单元对相变储能水箱蓄放热性能的影响,研究在保证水箱结构尺寸、相变材料种类和用量以及水箱进口水温和流速相同的前提下,利用Fluent软件对采用板型、圆柱型和球型封装单元的相变储能水箱以及无相变材料的传统水箱进行了模拟研究,并分析了各水箱在蓄热时间、放热时间、温度分布以及蓄放热量等方面的不同。模拟结果表明:封装单元形状改变会对水箱蓄放热性能产生一定的影响。在蓄放热过程中,3种相变储能水箱中球型单元水箱最先完成蓄放热,相比于板型和圆柱型单元水箱蓄热时间分别缩短10.4%和2.3%,放热时间缩短7%和2.3%。板型单元水箱完成蓄放热所需时间最长,相比于传统水箱,蓄热时间延长54.8%,放热时间延长38.7%。圆柱型单元水箱的蓄热量最大,约为41.612 MJ,较传统水箱提升了16.1%。板型单元水箱释放的热量最多,放热量为41.634 MJ,较传统水箱提升了16.2%。球型单元水箱由于封装单元形状和布置方式的不同,使得换热面积和相变区域较大,水箱内温度分布呈现出沿高度方向逐渐增加或降低的趋势,与其他两种相变储能水箱相比差异较大,且存在换热死区。

This paper was written under the premise of ensuring the same water tank structure size,phase change material type and dosage,and water temperature and flow rate at the tank’s inlet to investigate the impact of different shape encapsulation units on the heat storage and release performance of phase change energy storage tanks.Fluent software is applied to simulate the phase change energy storage tank with plate type,cylinder type,spherical type encapsulation unit,and the traditional water tank without phase change material.The research next examines the variations in each water tank’s heat storage duration,heat release time,temperature distribution,and heat storage and release capacity.The simulation results show that the shape change of the encapsulation unit will have some influence on the heat storage and release performance of the water tank.The spherical unit water tank is the first to complete heat storage and release during the heat storage and release process.The heat storage and release times are both reduced by 10%and 2.3%,respectively,when compared with the plate and cylinder unit water tanks.It takes the longest time for the plate unit water tank to complete heat storage and release,compared with the traditional water tank,the heat storage time is extended by 54.8%and the heat release time is extended by 38.7%.The cylindrical unit water tank has the highest heat storage capacity,at41.612 MJ,which is 16.1%more than a typical water tank.Plate unit water tank releases the most heat,the heat release capacity is 41.634 MJ,compared with the traditional water tank increased by 16.2%.The temperature distribution in the spherical unit water tank shows a trend of increasing or decreasing along the height direction,which is quite different from the other two-phase change energy storage tanks,and there is an inadequate heat transfer zone due to the different shape and arrangement of encapsulation units.