Numerical Analysis Of The Influence About Wake To Compressor Cascade Flow Field

Compressor is a core component of serving aero engine. Compressor development to someextent hampered the development of aviation engines. High load compressor is inevitableconfiguration for efficient aircraft engines. However, the high load also means easierseparation at blade surface flow. The flow separation will result in energy loss, making thecompressor can not reach the intended target. The magnitude blade technology, tandemcascade, surface blowing breathing, casing treatment and other processing techniques areapplied to reduce the loss of separation. The other means of unsteady excitation, such as jetflow and sound exciting, etc. can also effectively prevent the separation. Since the compressorturn and vane row staggered mutual movement, unsteady wake excitation becoming anappropriate natural excitation source. Rational use of wake enables compressor stageperformance enhancement. It`s a important research direction to the unsteady problem aboutcompressor, the influence of wake to the downstream cascade and suppression of boundarylayer development.In this paper, we study the effects of wake to compressor cascade flow field by numericalsimulation method. The main research is that the moving wake influence to the downstreamstator cascade flow field. By using the same resistance cylinder wake to replace the true rotorcascade wake, so as to achieve research determined wake effect to downstream cascade flowfield.The research of the influence about wake to compressor flow field look at the followingsituation.1:when the gap between the compressor inter stage is diffident, due to changes of the gap,the moving wake has a different performance in the static cascade diffuser channel.2:when the velocity of cylinder wake generator is different, due to the different velocity ofCylinder movement, resulting in changes of incident between wake and stator, so that thedirection of wake from the blade pressure surface toward the suction side of the blade to affectthe blade surface boundary layer. The effect of velocity of cylinder on the boundary layerfeatures are evaluated. 3:when several above-mentioned factors change, to analyze cascade losses of the totalpressure so as to determine what is advantage and disadvantages.Through this study found that the wake effects on downstream cascades associated withaxial clearance and wake of incident, when the wake flow to the suction side from the bladepressure surface, making boundary layer separation postponed. Axial clearance and cylindricalvelocity affects the efficiency of the downstream cascade. Rational use of unsteady wakecharacteristics can promote improved compressor performance.