Droplet Size Distribution on the Large-holed Compound Sieve Tray in the Spray Regime

The droplet size distribution with large-holed compound sieve tray operating in the spray regime is measured by using a double electrical probes technique in a cold model column of 400 mm diameter. The results indicate that the hole F-factor Fo and surface tension are the main factors which influence the liquid dispersion expressed by the Sauter mean diameter D32. A correlation of D32 on surface tension, viscosity, F-factor, weir height and liquid flow rate is proposed.

界面湿润性对自由下落在基体平面上液珠扁平化的影响

为了探讨飞溅层片与基体界面间湿润性对金属液珠扁平化行为的影响，用物理气相沉积方法在不同温度下，先在基体表面上涂覆金膜。用常压氮气作为下落金属液珠的气氛，以防止其氧化。在此条件下确认落下液珠成为层片的形貌。经试验认定，室温下这些层片为飞溅型，但在高温下则为盘形。室温断面组织为各向同性的粗颗粒组织，但高温时则为细的柱状晶颗粒，颗粒的大小与基体的温度有关。当金属基体上的飞溅层片组织的转变温度高于裸体基体上温度时，低压下的层片横断面组织直至室温都为细的柱状组织。这些结果表明，与常压氮气下比较，低压下金属液珠润湿较好，且对液珠的扁平化有明显的作用。