Effect of Flow Channel Cross Section Shape on the Performance of Heat Storage Structure

A numerical simulation is carried out for the thermal storage process in a heat storage device with magnesia bricks as thermal energy storage medium. Three types of cross section shapes (square, hexagon, circle) of the flow channel are considered with the inlet air temperature as high as 1023K. The perssure drop, temperature distribution and temperature uniformity of the flow channel are obtained. The results show that the pressure drop of the flow channel with circle cross section is the lowest when the Reynolds number is less than 2300 (in this case the inlet velocity is 5m/s), While when the Reynolds number is more than 2300, the flow channel with square cross section has the lowest pressure drop. The thermal storage time of the heat storage device decreases with the increase of air velocity. The temperature distribution of the flow channel indicates that the flow channel with hexagon cross section has the best comprehensive performance.