旋转失速和喘振的统一模型

A UNIFIED MODEL FOR ROTATING STALL AND SURGE

一、前言 旋转失速和喘振是压气机工作不稳定的两种典型性态。早在1955年Emmons等人已通过实验揭示了这两种不稳定工作的实质并提出了说明其机理的流动模型。但对这两种不稳定性态的相互关系没有进一步的揭露,长期以来停留在旋转失速是喘振的起源和先导这一假定上。本文倾向于翼型分离导致周向自激振荡和轴向自激振荡并发的论点,并提出了支持这种论点的流动模型。

Recently supported by the funds of the national natural science, we have tested and mes-sured the instability behavior of compressor in detail with hot-wire, hot-film probes and transient pressure 3-hole probes on sigle rotor, single stage and multi-stage compressor respectively. After analyzing signals with the power spectra and correlation techniques, it is foundthat there are two kinds of disturbances--peripheric oscillation and axial oscillation inthe flow. On the basis of this fact, the argue that the flow separation from airfoils results in penpheric oscillation and axial oscillation simultaneously is proposed, and a new model to des' cribe flow destabilizing mechanism is constructed by the paper.For the stability problem of multistage axial flow compressors, it is of practical meaning to investigate its stability limit, inclusive of the rotating stall margin. The preliminary results of this investigation shows that in high speed region the stability limit is equivalent to a surge line, that in middle speed region the stability limit is indeed a stall line and that in low speed the stability limit has two branches, one is the stall line of the whole compressor, the other is the rotating stall inception margin of the first stage. Both has the same importance from the point of view of engine safety.finally the mathematical methods for predicting this stability limit is discussed.