Investigation On Aerodynamic Design Method And Internal Flow Of Micro Gas Turbine

Micro gas turbine is widely used in the fields of distributed and portable energyresources. Industry and civilian have urgently demands on the micro gas turbine. Howeverthe domestic investigation on micro gas turbine is not thoroughly deep at the present time.Based on the above situation, this dissertation carried out investigations on micro gasturbine aerodynamic design and numerical simulation.This dissertation is aimed at designing high efficiency micro compressor and microturbine, taking its operation and flow features into account; It is also aimed towardsunderstanding the characteristics of flow and heat transfer by mean of numericalsimulation. To achieve the above objectives, the following studies were carried out: (1) theinfluences of turbulence model and mesh density on the numerical results. (2) Discussionson the aerodynamic design method for micro compressor and turbine. (3) The effects of tipleakage flow, Reynolds number and heat transfer on micro compressor and turbine were.The details of the contents are as follows:(1) Investigation of different mesh densities on the computational result of microturbine was carried out to guarantee the reliability of the CFD results.Computations were carried out at the same mesh density with the assumptions ofall laminar flow and all turbulent flow, respectively. And the results show that thereis little difference between the two results with different flow assumption.(2) The choosing method of the overall design parameters and the method ofaerodynamic design are proposed. The key issues and difficulties in the design arepointed out. A micro compressor and a micro turbine with high efficiency areobtained by careful tuning on the design.(3) In the numerical investigation of micro compressor, the effects of rotor tip leakage flow on the secondary flow patterns, rotor and stator flow field, and overallperformance are investigated at first. Secondly, the effects of Reynolds number onmicro compressor flow, heat transfer and overall performance are analyzed. Finally,based on the investigation of the effects of heat transfer on flow and heat transfer inmicro compressor, the dissertation proposed a calculation method of thecompressor total to total efficiency, deduced a thermal analysis model, A bettercompressor design is resulted by using the proposed iterative procedure betweenthe thermal model analysis and CFD simulation.(4) In the numerical investigation of micro turbine, first, the effects of rotor tip leakageflow on the secondary flow, rotor and stator flow field and overall performance arecarried out. Secondly, the effects of Reynolds number on flow and heat transfer inmicro turbine and turbine performance are analyzed. Finally, a calculation methodof the turbine total to total efficiency and a thermal analysis model are proposed,respectively. The comparisons between the results of thermal analysis model andCFD are made. The reason that the thermal analysis model predicted less mass flowand static pressure ratio is pointed out.