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 reflux pressure of the involute leaf-type three-lobe Roots blower under supercritical flow conditions was analyzed. The backflow area was calculated, and the flow function and critical pressure ratio in the supercritical flow state were given. The back pressure calculation of the circular and involute sections of the pinion of the three-bladed impeller was carried out. The production example shows that the backflow gap of the three-bladed impeller changes rapidly, and the critical pressure is affected by the critical pressure ratio and the discharge pressure. The supercritical reflux occurs at the beginning of the arc segment and involute segment of the trilobe impeller.