Comparison study on operation and mechanical characteristics of liquid sodium thermoclinic heat storage tank using different solid filling materials

Abstract

This study evaluates and compares the effects of five actual solid filling materials (SFMs) on the operation and mechanical characteristics of liquid sodium thermoclinic heat storage (THS) tank, including the quartzite, high-temperature concrete, copper foam, silicon carbide and alumina ceramics. By utilizing the computational fluid dynamics method, the charging, discharging and mechanical performances of the THS tank using different SFMs as well as with no SFM are compared. The results demonstrate that the introduction of SFM can enhance the charging and discharging performances of the THS tank. The high-temperature concrete can lead to the maximum average discharging power of 4.93×105 J/s and the second maximum total discharging quantity of 7.55×109 J, and the alumina ceramics could bring the maximum total discharging quantity of 8.59×109 J and the second maximum average discharging power of 4.77×105 J/s. The THS tank using high-temperature concrete has the largest discharging efficiency of 90.14% as well as the smallest peak maximum mechanical stress of the THS tank wall (42.4 MPa). The THS tank with no SFM has the smallest total charging quantity and lowest discharging efficiency, which are 4.62×109 J and 77.84%. In general, the THS tanks using alumina ceramics and high-temperature concrete both have better operation performances, and the high-temperature concrete can bring the best mechanical performance of the THS tank.