相变过程体积变化率的实验研究

EXPERIMENTAL RESEARCH OF VOLUMETRIC CHANGE RATE DURING PHASE CHANGE PROCESS

建立了一套实验装置研究相变过程中的体积变化规律及其影响因素。以正十六烷为相变材料,在不同的初始温度和边界温度下,对凝固过程和熔解过程的体积变化率进行测量分析。研究表明:在相变初始阶段,体积变化速率较大。体积变化速率的大小与相变速率的大小有关,所有影响相变速率的因素将影响体积变化速率。在压力的作用下,熔解过程的总体积变化率小于凝固过程的总体积变化率。对同体积的液态正十六烷,在相同的外界压力下,较小的体积膨胀率可获得较大的输出功率。

An experimental device to research the volumetric change rate during phase transition process and the influencing factors was constructed. Hexadecane was chosen as the phase change material. Volumetric change rate of hexadecane was measured and analyzed during solidification and melting process at different initial and boundary temperatures. The result showed that the speed of volume change is large at the initial stage of phase change process, the volumetric change rate is related to phase change rate. All that affect the phase change rate will affect the volumetric change rate. The total volumetric change rate of melting process is smaller than solidification process under external pressure. Hexadecane with same volume can output more power at less volumetric expansion rate under same external pressure.