低熔点合金相变换热特性实验研究

Experiment Study on Phase Change Heat Transfer Characteristics of Low-melting-point Alloy

本文针对熔点为70°的Bi-Cd-Pb-Sn低熔点合金的相变换热特性开展了实验研究,讨论了冷却水流量对冷却速率及相界面移动速率的影响。结果表明:低熔点合金在冷却过程中出现明显的相变带,相变潜热释放完后合金温度出现陡降;冷却水流量越大相界面的移动速率越快,当Q>80 L·h^(-1)时流量对固液相界面的移动速率影响减小,相同流量下固液相界面的移动速率随热阻的增加逐渐减小。

In present study,the phase- change heat transfer characteristics of the low- meltingpoint Bi-Cd-Pb-Sn alloy with melting point is 70℃ was investigated by experiment,and the effects of the flow rates of cooling water on the variations of cooling rates and travelling speeds of the phase-transformed interfaces have been discussed.The experimental results showed that the low-melting-point alloy has an obvious phase-transformed interface in the cooling process and the alloy cooling rapidly after the latent heat releases.In addition,the speed of the phase-transformed interface increases with increasing the flow rate of cooling water,but when the flow rate of cooling water is above 80 L·h^(-1),the speed of the phase-transformed interface starts to decrease.Furthermore,at the same travelling speed of the interface obviously decreases with increasing the thermal resistance.