| Centrifugal compressors play an important role in the field of aviation and spaceflight, energy, chemical engineering and metallurgy. In some large compressors, such as that used in the ethene and chemical fertilizer devices, complementary gases often need to be added between centrifugal compressor stages for the requirement of technologic process. However, if the complementary gases is not added properly, it may result in the inlet flow distortion in the next stage. Because the development of the fundamental stages was based on the uniform inlet flow condition, the inlet flow distortion of the next stage may cause the inlet flow angle changing in a wide scope, which may not only affect the efficiency of the machine, more seriously, it may cause rotating stall and thus threaten the safety and economic operation of the machine. Therefore, it's of great significance that research the method and structure design of complementary gas added in-between stages.The structural design and flow optimization for the complementary gas added in-between stages was studied in this thesis, based on two typical centrifugal compressors H605 and H856. A numerical analytic system was developed, using commercial software such as Pro/E,ICEM-CFD,STAR-CD and NUMECA. A new volute structure design for the complementary gas flow path was proposed, so that the flow flux was distributed properly in the circumferential direction, and the guide vane was designed to obtain the proper flow direction. The return channel blades, guide vane and the meridian flow path were experimented numerically in an attempt to solve the problem of the next stage inlet distortion. As a consequence, the aerodynamic loss was reduced, the rotating stall could be avoided, and the efficiency and the safety operation of the compressor could be safeguarded.The research results presented in this thesis may provide some guideline for the design of the compressors with complementary gas flow. |
PDF Full Text Request