The Research Of The Bleeding Structure And Bleeding Pipe System Design Of The Axial Compressor

The bleeding system of compressor is a very important system of gas turbine. No matter the protection from surge for START/STOP of the gas turbine or the supply of cooling air for every stage of turbine, all accomplishents must be through the bleeding system for compressor. A reasonable and efficient compressor bleeding system is the guarantee for the safe and stable running and START/STOP of the whole machine.The compressor bleeding system includes two main parts, the inner aspirating structure and outer pipe system. Well design of the inner aspirating structure will reduces the loss of the compressor. Suction-side aspiration is one of the bleeding methods for large-scale gas turbine compressor. The main research of this article is the influence of suction-side aspiration on stage parameters and flow field, and the development of a bleeding pipe network design system.During the research of inner aspirating structure three bleeding methods are investigated, there are single-cavity full-height aspiration, single-cavity partial-height aspiration and double-cavity partial-height aspiration. Different size of bleeding cavity and different bleeding mass flow are taken into account for full-height aspiration and partial-height aspiration. Further more, different bleeding slot width is considered for double-cavity partial-height aspiration.The research result is, the more the effective bleeding mass flow the better the stage efficiency, but the bleeding mass flow can't be too high or the main flow will be bled out, and too high bleed mass flow will cause choke flow in bleeding slot and cavity, consequently make the efficiency unincrease with the increase of bleeding mass flow even decrease in some situation. The research still indicates that, the bleeding mass flow distribution of the bleeding slot is uncontrollable for single-cavity aspiration though the bleeding structure is simple opposite to the double-cavity aspiration. The factors above must be considered together when the inner compressor bleeding structure is designed. The popular node-branch method is brought into the research of outer bleeding pipe system. A one-dimensional mathematical model is set up for single-phase compressible flow with heat-transfer. Implicit mehod is used to improve the calculation speed in order to obtain a quick answer for the flow parameters of a complexed pipe network, for example, the pressure and temperature of each node and the mass flow of each branch pipe. This article combines the inner aspirating structure design and outer bleeding pipe system design to establish a basical compressor bleeding design system.