过冷水雾相变传播及温度场的实验研究

Experimental Investigation of the Phase Transition and Temperature Field in Supercooled Fog

实验表明在过冷水雾相变传播过程中伴随有脉冲型单峰形式的温度上升 ,相变传播速度约为 1.2cm/s ,温度的波形和峰值以及相变的传播速度与过冷水雾的初始温度基本无关 .据此对过冷水雾冰晶繁生机制作了探讨 .

Experimental investigation shows that in supercooled fog adequate addition of small ice crystals leads to the propagation of phase transition. In the course of the propagation, a temperature transition of a pulse like shape is observed on the interface between the supercooled fog and ice crystals. It is measured that the rising time in the transition is within 32 ms, and the restoration time is about 200 ms, while the speed of the propagation is about 1.2 cm/s. It is also found that the temperature waveform ( including its peek value ) and the propagation speed are both independent of the initial temperature of the fog. The pulse like temperature transition shows that the latent heat in vaporization is almost equal to that in condensation, and the dramatic rising of temperature dose not correspond to the portion of freezing latent heat in condensation, but to the release of the latent heat in the freeze of the supercooled water droplets. Based on these observations, we also discuss the mechanism of the ice crystal proliferation in supercooled fog.