敲击振动触发过冷三水醋酸钠(SAT)凝固释能实验研究

EXPERIMENTAL INVESTIGATION ON TRIGGERING SOLIDIFICATION OF SUPERCOOLED SODIUM ACETATE TRIHYDRATE(SAT)BY PERCUSSION VIBRATION

利用实心钢球敲击不锈钢圆角矩形蓄热单元表面,根据测定诱导时间和触发敲击次数实验研究不同敲击动量及位置对单元内过冷SAT溶液触发凝固性能的影响。结果表明,敲击振动是触发该过冷水合盐相变材料凝固释能的有效方法,结晶最大温升速率为3℃/s,且最高表面温度达到53℃,比理论相变温度低5℃;凝固从开始触发位置为中心以8~10 mm/s的速度向四周扩散。敲击动量越大,诱导时间越短,最短仅为10 s;敲击位置靠近密封盖或蓄热单元边角诱导时间更短。实验结果为SAT过冷蓄存太阳热能用于采暖或热水供应释能控制提供方法和指导。

Solid steel balls were applied to hit the surface of a rounded-rectangular thermal storage unit made of stainless steel for solidification activation,and the effects of percussion momentums and positions on triggering solidification of the supercooled sodium acetate trihydrate(SAT)solution in the units were experimentally investigated based on the measured crystallization induction time and percussion number.The results show that the percussion vibration is an effective method to activate solidification for energy release of this supercooled salt hydrate phase change material,and the maximum rate of temperature rise is 3℃/s when the solidification is initiated.The surface temperature rises up to as high as 53℃after the solidification activation,which is about 5℃lower than the theoretical phase transition temperature.Also,the solidification spreads from the activation position to the surrounding area at the speed of 8-10 mm/s.The results confirmed that the induction time decreases for larger percussion momentum with the minimum induction time of only 10 s.The induction time is also reduced when the percussion is exerted near the sealing cover or the edge corner of the heat storage unit.The results provide control methods for releasing the energy stored in supercooled SAT solution for space heating or hot water supply.