高温相变蓄热电锅炉结构优化与数值模拟

Structural Optimization and Numerical Simulation of a High Temperature Phase Change Thermal Storage Electric Boiler

对高温相变蓄热式电锅炉内蓄热模块的结构进行优化,首先根据供暖热负荷需求对高温相变蓄热式电锅炉进行了相关设计计算,在蓄热式电锅炉供热功率确定的情况下,选用合理的高温相变蓄热材料及电加热元件.在这些条件完全相同的情况下,采用FLUENT模拟研究了平板型与锯齿型蓄热板采用2种不同布置方式的蓄热效果,通过比较4种不同模型中监测点的温度变化、不同结构的模型完成蓄热所需的时间及高温相变蓄热材料的液相率,得到:1)分流通道的布置方式更优于"蛇"形通道,除显热储热阶段提前完成外,相变储热阶段也缩小0.22h;2)锯齿型蓄热板的换热效果要优于平板型蓄热板,在蓄热板布置方式相同的情况下,相变储热阶段提前0.20 h完成;3)锯齿板分流通道(模型(d))蓄热模块的蓄热效果是较优的,其在布置方式及换热板的形貌上都得到优化,使得传热速率不仅加快,潜热储热时间也大大缩短,在相同的加热时间,得以储存更多的热量,避免了平板"蛇"形通道蓄热模块(模型(a))储热不完全的缺陷.

The research object of this paper is a high temperature phase change thermal storage electric boiler.The related design and calculation of the high temperature phase change heat storage electric boiler were first made according to the heating load demand,then the reasonable high temperature phase change heat storage material and the electric heating module were selected under the condition of a determined electric boiler power,and the structure of the heat storage module was finally optimized.The FLUENT software was used to simulate the regenerative effect of the flat-plate type and the sawtooth type regenerator through two different layout methods.By comparing the temperature changes of the monitoring points in the four different models,the time required for the heat storage and the liquid phase rate of the high temperature phase change storage material.The following conclusions were obtained.First,the layouts of the distributary channel were better than that of the serpentine channel.In addition,the sensible heat storage stage was completed ahead of schedule,and the phase change heat storage stage was reduced by 0.22 h.Second,the heat transfer effect of sawtooth regenerative plate is better than that of flat regenerative plate.The phase change heat storage stage of sawtooth regenerative plate was completed 0.20 h ahead of schedule under the same arrangement of regenerative plate.Third,the regenerative effect of the sawtooth distributary channel(model(d))was the best because it was optimized in the layout and the shape,which led to the heat transfer rate,and the latent heat storage time was both accelerated.It can store more heat in the same heating time,avoiding the defect of incomplete storage of the flat serpentine channel(model(a)).