Research On Performance Of Centrifugal Compressor Diffuser And Whole Machine For WD095 Micro-Gas Turbine

Micro-Gas Turbine (MGT), which is efficient, flexible, reliable and small volume, is widely used in distributed power generation, reserve power, heat and power cogeneration, parallel generation, peak load power generation. It can be applied in both central city and remote areas, even rural suburbs. In addition, the Mica-Gas Turbine has the advantage in the civilian transportation (hybrid vehicles), military vehicles and land or sea border frontier defense.The centrifugal compressor, as an important component part of Micro-Gas Turbine, its performance is directly related to the level of micro-gas turbine efficiency. The Centrifugal Compressor flow parts of WD095 Micro-turbine were numerically studied. Different diffuser structure was comprehensively investigated to discover the most efficient structure for the MGT centrifugal compressor.In the research and analysis work of the MGT Centrifugal Compressor, the turbine commercial CFD software NUMECA was used. First of all, the influence of diffuser meridian shape with different width ratio on MGT centrifugal compressor was studied. The aerodynamic results show that the best width ratio range of the diffuser meridian channel is 0.5 to 0.7 after comparing.The Second, the tandem cascade application in MGT diffuser was discussed. And the first blades outlet angle of tandem cascade was studied. It is found that when the first row blades outlet angle is 31.5°, the first blades coincide with the second blades can form a converging region of the flow channel. At this zone the diffusion velocity ratio DVR and the total pressure loss coefficient are minimum, while the polytropic efficiency, the pressure ratio and the total pressure recovery coefficient are maximum.At last, base on these studies, the full process characteristics calculation was done of the whole centrifugal compressor under design speed, and the characteristic curve was achieved. It reflects the centrifugal compressor has relatively smooth characteristics under design speed, but the high efficiency zone is not wide enough. After the whole machine with converging channel diffuser being calculated, it shows that the performance of the compressor with converging channel diffuser is obviously superior to the one of the compressor with equal width channel diffuser. The polytropic efficiency is improved by 2.31%, and the total compression ratio is increased by 1.85%. After the whole machine with tandem cascade diffuser being studied under design condition, it indicates the centrifugal compressor has better performance when the first blades are close to suction side of the second blades. And the outlet angle is 31.5°, the flow field distribute is best compared to other structures.