自吸式文丘里洗涤器引射特性及其影响因素

摘要

The main factors that affect injection performance of self-priming Venturi scrubber were analyzed based on the Bernoulli equation, the influence of these factors was further verified by experiment. Injection flow rate of self-priming Venturi scrubber depended mainly on static pressure differential, cross-sectional area, height difference and liquid channel resistance coefficient on both sides of suction port. In the case of no injection, the static pressure at outlet cross section of liquid flow was equal to the pressure at nozzle wall, higher than the average pressure and center pressure at nozzle exit. In the case of injecting liquid, an additional pressure increment was generated at gas-liquid interface because of momentum exchange. Pressure increment would spread around in the form of pressure waves to the entire cross-section, resulting in further reduction of effective pressure difference for injection. When effective injection pressure difference was limited, liquid channel area and resistance coefficient became important for injection flow. On this occasion,it was more effective to enlarge the area ratio between nozzle and sleeve and enlarge nozzle diameter, to increase liquid channel area and reduce resistance coefficient, which was effective in increasing liquid flow.%以自吸式文丘里洗涤器为研究对象，基于伯努利方程分析了影响其引射量的主要因素，并通过实验对各因素进行分析验证。结果表明，自吸式文丘里洗涤器的引射量主要取决于吸液口两侧的静压差、截面积、高度差以及液体在流动通道内的阻力系数。当文丘里洗涤器不引射液体时，液体流动通道出口截面上的静压力与喷嘴壁面处的压力相等，远高于喷嘴出口中心和出口平均压力；当文丘里洗涤器引射液体时，气液两相的动量交换作用，会在气液界面处产生额外的压力增量，并以压力波的形式向整个截面传递，导致有效的吸液压差进一步降低。当吸液压差较小时，液体的流通面积和阻力系数对引射量的影响明显，通过增大外套管与喷嘴面积比同时增大喷管出口直径的方法，一方面能够增大液体流通面积，另一方面也减小了液相流动阻力，对于改善液体引射量是有效的。