针对煤液化笼式调节阀内普遍存在的空蚀问题，基于RANS方程、Mixture多相流模型及Zwart空化模型，对阀门内部的空化流动进行了数值模拟研究，确定了阀笼失效的主要原因；基于压降分析和预测空化位置，提出了调节阀阀笼的结构改进方案并进行了验证分析。结果表明，调节阀内空化气相集中分布于阀笼内层节流孔，是阀笼中内层节流孔内壁及阀笼内壁存在明显失效缺陷的主要原因；阀笼内层节流孔内空化严重发生的主要原因为降压级数不够，导致第二级压降过快，产生局部低压区，空化剧烈发生；内层节流孔深度较大，导致空化在整个内层节流孔内充分发展；提出将内层节流直孔调整为阶梯孔的结构改进方案，可有效降低空化强度和分布范围。本工作对煤直接液化工程中的笼式调节阀的设计和研究具有一定参考价值。

Aiming at the common cavitation problem of the cage-typed control valve in the coal liquefaction industry, based on the RANS equation, the mixture multiphase flow model and the Zwart cavitation model, a numerical simulation study of the cavitation flow inside the valve was carried out, and the main reason of the cage's failure was determined. Based on the pressure drop analysis and prediction of the cavitation position, a structural improvement scheme of the control valve's cage was proposed and verified. The results showed that the cavitation vapor in the control valve was concentrated in the inner orifice of the cage, which was the main reason for the obvious failure defects in the inner wall of the inner orifice and the cage. Based on the comparisions between pressure drop and cavitation vapor distributions on the horizontal cross section of the valve cage, the two reasons for the serious cavitation in the inner orifice of the cage were concluded. Firstly, the number of depressurization stages was not enough, which led to excessive pressure drop in the second stage, resulting in a local low pressure area, and cavitation occurs violently. Secondly, the depth of the inner orifice was too large, resulting in fully developed cavitation in the inner layer orifice of the cage. Thus, the structure improvement scheme was proposed to control the depressurization intensity and the occurrence area for cavitation development in the cage. By adjusting the straight orifice in the inner layer of the valve cage to stepped orifice, the adjustment from two-stage to three-stage depressurization was realized, which solved the problem of local low pressure area caused by excessive pressure drop, and effectively reduced the strength of cavitation initiation and the distribution range of cavitation. This work has a certain reference value for the design and research of the cage-typed control valve in the coal liquefaction industry.