入口旋流对旋转篦齿封严特性的影响研究

Study for Effects of Inlet Swirl on Flow Characteristic of Rotating Labyrinth Sealing

旋转因素对篦齿的封严特性具有重要的影响,数值研究了具有不同旋流比的入口气流对旋转直篦齿泄漏特性和风阻特性的影响。通过与试验数据对比,进行了湍流模型的选取和验证。在不同压比工况下,获得了不同入口气流旋流比对篦齿的泄漏特性、出口旋流和风阻温升的影响。结果表明:入口旋流比对泄漏系数影响较大,旋流比增加泄漏系数降低;不同入口旋流比对出口旋流的影响不同,甚至影响趋势相反;不同入口旋流条件下,风阻温升均随压比增大而减小;当压比大于1.3时,入口旋流比越大,风阻温升越小;当压比小于1.3时,风阻温升随入口旋流比增大而增高。最后,引入"有效总压"参数,它能够更准确指导分析入口旋流对篦齿泄漏流量影响。

The swirl is one of important factors on the performances of a labyrinth sealing.Its effects on discharge and windage performance of a straight-through labyrinth were numerically studied in cases of various inlet flow states with different swirl ratios.Based on the experimental data,turbulence model was verified.At various pressure ratios,discharge characteristics,windage heating characteristics,and outlet swirl ratios for different inlet swirls were studied closely.Results indicated that the inlet swirl has obvious effect on the discharge.With the increase of inlet swirl the discharge coefficient falls.The presence of inlet swirl results in various even opposite influence on outlet swirl which depends on its number magnitude.The windage temperature rise all decreases when the pressure ratio rises at different inlet swirl ratios.However,it shows opposite trend for different pressure ratio level.Specifically,when pressure ratio is less than 1.3,the windage rise is high for a high inlet swirl ratio;but when pressure ratio is over 1.3,the windage rise falls with the increase of inlet swirl.Finally,an effective total pressure is proposed to help analyze the effects of inlet swirl on sealing discharge.