Stabilizing Treatment Of Vaneless Diffuser Of Centrifugal Compressor Based On Sloting Technology

Centrifugal compressor is widely used in petroleum,metallurgy,aerospace and other technical fields because of its large amount of compressed gas,simple structure and reliable operation.Stall and surge are flow instability phenomena in the compressor at low flow rate,which are important factors to determine the stable working range of centrifugal compressor.Delaying stall and preventing surge are effective measures to expand the normal operating range of compressor,which is an important part of centrifugal compressor design and research.Combined with the application status of centrifugal compressors in engineering practice,a small and micro centrifugal compressor is taken as the research object.By comparing the flow field characteristics of inorganic casing and containing casing,the stall phenomenon that affects safe operation under the condition of small flow is pointed out.On the premise that the optimal casing treatment parameters were obtained after comparing the effects of different casing treatment schemes on compressor parameters through orthogonal tests,the flow conditions and the stability expansion mechanism of the casing treatment method in the vaneless diffused under the clogging condition were defined.It is found that the flow field in the vaneless diffusor of centrifugal compressor without casing treatment has a stall-off mass that begins to form from the side of the vaneless diffusor wheel cover near the diffusor inlet and gradually takes up all the diffusor passage range.And through orthogonal experiment,it is concluded that the optimal casing treatment scheme is applied to the centrifugal compressor after the leaves on the diffuser,did not change the stall number from the group,but through the suction effect to low energy fluid intake,reducing the low-energy fluid and the normal flow of fluid in the contact area and contact time,effectively delay from mass of evolution to the diffuser flow field of the time.It is also found that while the casing treatment method can widen the stable working range of centrifugal compressor,the isentropic efficiency,total pressure ratio and static pressure recovery coefficient are all affected to varying degrees.It provides a theoretical basis for the casing treatment in the vaneless diffused of centrifugal compressor in engineering design.