超临界流动状态下三叶罗茨风机的回流压力分析

Analysis on Back Flow Pressure of Three Leaves Roots Blowers in Super-Critical Flowing State

对渐开线叶型三叶罗茨风机的超临界流动状态下的回流压力进行了分析。计算出回流面积,给出超临界流动状态下的流函数、临界压力比,进行了三叶叶轮的销齿圆弧段及渐开线段的回流压力计算。生产实例表明,三叶叶轮的回流缝隙变化较快,临界压力受临界压力比、排气压力影响,超临界状态回流发生在三叶叶轮的销齿圆弧段及渐开线段的开始部分。

The back flow pressure of Roots blowers with three involute leaves in super-critical flowing state is investigated. The back flow area is calculated. The stream function and critical pressure ratio are given. And the back flow pressure of arc section and involute section of three impellers is calculated. The practical example shows that the back flow slots of three impellers change quickly, and the critical pressure is influenced by the critical pressure ratio and exhaust pressure. The super--critical back flow occurs in the beginning part of arc section and involute section of three impellers.