限速切断阀的限定流量特性研究

限速切断阀由于阀口开度较大，与阀口压差相比其内部流道阻力不能忽略，从而用传统的解析方法不能对限定流量准确计算。以限速切断阀具体结构为计算实例，采用RNG k-ε湍流模型对限速切断阀的流场进行三维数值仿真，并与试验测试和理论计算结果进行了比较与分析。结果表明流场仿真所预测的限定流量与试验测量结果吻合良好。

Investigation and Analysis of Flow Characteristic of Overspeed Chopper

An overspeed chopper is widely used in hydraulic lifting systems to avoid an accidental overspeed drop. Because of the big opening of this type valve, its internal pressure drop behind orifice can not be omitted, which makes the traditional theoretical calculation method can not determinate its characteristics precisely. Based on a typical overspeed chopper used in hydraulic elevator, a means of 3 D flow simulation was used to investigate its complex internal flow and to predict its limited flow rate. The limited flow rates obtained from the computational fluid dynamics (CFD) and theoretical analysis agree well with the experimental values over a range of relatively small valve openings. However, in large valve openings, the CFD results were better than those from the theoretical calculations.