横摇对泡沫金属内液体疏泄特性影响的实验研究

Experimental Study of Rolling Impact on Liquid Drainage Performance in Metal Foam

泡沫金属应用于海上管壳式换热器时,需要保证海上工况下冷凝液体从泡沫金属中及时疏泄,为此需要明确泡沫金属内液体的疏泄性能。本文搭建了滴注疏泄测试实验台,在稳定和横摇工况下分别测量了孔密度分别为5、10、20和40 PPI的泡沫金属内液体疏泄后的单位体积存液量。结果表明:随着孔密度从5 PPI增加到40 PPI,液体存在泡沫金属内的形态逐渐从部分悬挂液滴变成完整液层,单位体积存液量约增加了300%;随着横摇角度和横摇频率的增大,泡沫金属的疏泄性能变好,存液量减小;孔密度10为PPI的泡沫金属在横摇工况下疏泄性能最优,而孔密度为40 PPI的疏泄性能最差,存液量在实验工况范围内最多变化了45%和8%。

The premise of metal foam tubes applied in floating shell-and-tube heat exchanger is that the condensate can be well drained out of metal foam,thus the liquid drainage performance for the metal foam under sloshing condition should be investigated.In the present study,the droplets-injection test apparatus is designed to measure the liquid retention of metal foam with pore density of 5,10,20,and 40 PPI under steady condition and rolling condition.The research results show that,as pore density increases from 5 PPI to 40 PPI,the shape of liquid in metal foam changes from partial droplets to complete liquid layer,and the mass of liquid retention is increased by 300%.With the increase of rolling angle and frequency,the drainage performance promotes and the liquid retention in metal foam decreases.Under the rolling condition,10 PPI and 40 PPI metal foam has the best and worst drainage performance respectively,and the respective decrement of liquid retention are 45%and 8%maximally.