相变蓄热器多温位释热特性研究

Study on multi-temperature heat release characteristics of phase change heat storage

为了探究相变蓄热器在多温位释热过程中的性能,采用ANSYS Fluent对蓄热器单元模块进行建模,对比试验结果得出其相变材料平均温度误差为4.8%,验证了该模型的准确性,然后通过改变蓄热器边界条件(第1组工况恒热流边界条件高温级652.4 W/m^(2),低温级693.0 W/m^(2);第2组高温级382.3 W/m^(2),低温级810.1 W/m^(2);第3组高温级905.6 W/m^(2),低温级454.0 W/m^(2)),研究分析其高低温级释热性能。结果表明:第1组工况高低温级液相率变化速率最为一致、温度变化最为均匀;第2组低温级液相率和温度下降更迅速;第3组高温级液相率和温度下降更迅速。该结果可为多温位释热相变蓄热器的结构优化研究提供参考。

In order to investigate the performance of the phase change heat storage in the multi-temperature heat release process,ANSYS Fluent was used to establish the model of the heat storage unit module.By comparing with the experimental results,the average temperature error of the phase change material was 4.8%,which verified the accuracy of the model.Then,by changing the boundary conditions of the heat storage(The heat flux density of high temperature and low temperature stage of constant heat flux boundary conditions in the first group of operating conditions is 652.4 W/m^(2)and 693.0 W/m^(2),respectively;the heat flux density of high temperature and low temperature stage in second group is 382.3 W/m^(2)and 810.1 W/m^(2),respectively;and the heat flux density of high temperature and low temperature stage in third group is 905.6 W/m^(2)and 454.0 W/m^(2),respectively),the heat release performance of its high and low temperature stage was studied and analyzed.The results show that the change rates of liquid fractions of the high and low temperature stage in the first group of operating conditions are most consistent,and temperature change is most uniform;the liquid fraction and the PCM temperature of low temperature stage in second group decrease more rapidly.The liquid fraction and the temperature of high temperature stage in third group decrease more rapidly.These results can provide a reference for the structural optimization of multi-temperature heat release phase change heat storage.