Experimental studies are carried out at a low speed axial compressor with five different rotor/stator gaps. Analysis of the effect of axial spacing of two successive blade rows on the measured mean flow coefficient at...Experimental studies are carried out at a low speed axial compressor with five different rotor/stator gaps. Analysis of the effect of axial spacing of two successive blade rows on the measured mean flow coefficient at stall inception and on the flow range of compressor under multi-cell rotating stall operating conditions proves that the stator can suppress the flow disturbance in the compressor and strengthen the stability of the compressor. Experimental data show that the stall flow coefficient decreases by reducing the axial spacing of successive blade rows. Moreover, by reducing the axial spacing, the stall pattern transition pace from multi-cell stall to single-cell stall can be shifted. And the compressor directly slips into single-cell stall at 21.0% CR axial spacing. By analyzing the pressure fluctuation closed to the surge line, it can be known that there exists an eigenfrequency where the amplitude of the oscillating pressure suddenly and dramatically increases as the compressor runs close to the surge line and this pressure disturbance is relevant to the compressor instability.展开更多
In order to study the effects of wet compression on a transonic compressor,a full 3-D steady numerical simulation was carried out under varying conditions.Different injected water flow rates and droplet diameters were...In order to study the effects of wet compression on a transonic compressor,a full 3-D steady numerical simulation was carried out under varying conditions.Different injected water flow rates and droplet diameters were considered.The effect of wet compression on the shock,separated flow,pressure ratio,and efficiency was investigated.Additionally,the effect of wet compression on the tip clearance when the compressor runs in the near-stall and stall situations was emphasized.Analysis of the results shows that the range of stable operation is extended,and that the pressure ratio and inlet air flow rate are also increased at the near-stall point.In addition,it seems that there is an optimum size of the droplet diameter.展开更多
Unsteady behaviors as well as unsteady cascade flow fields of a single-stage axial flow compressor were experi- mentally investigated by detail measurements of unsteady performance characteristics and casing wall pres...Unsteady behaviors as well as unsteady cascade flow fields of a single-stage axial flow compressor were experi- mentally investigated by detail measurements of unsteady performance characteristics and casing wall pressure and internal flow velocity fluctuations. The main feature of the test compressor is a capacity tank connected di- rectly to the compressor outlet in series through slits and a concentric duplex pipe, and also jet nozzles in order to inject compressed air toward the rotor tip region. Research attention is focused on the post-stall characteristics of surge and rotating stall which occur simultaneously. When the compressor was connected to the capacity tank, surge was generated with rotating stall in accordance with the capacitance increment of whole compressor system The surge behavior changed irregularly with throttling valve installed behind the compressor, and several types of surge cycles were observed. In addition, the surge cycle changed by jet injection to the rotor tip region. The re- suits suggested that the blockages of the cascade flow which were generated by a stall cell play an important role in deciding the surge behaviors.展开更多
文摘Experimental studies are carried out at a low speed axial compressor with five different rotor/stator gaps. Analysis of the effect of axial spacing of two successive blade rows on the measured mean flow coefficient at stall inception and on the flow range of compressor under multi-cell rotating stall operating conditions proves that the stator can suppress the flow disturbance in the compressor and strengthen the stability of the compressor. Experimental data show that the stall flow coefficient decreases by reducing the axial spacing of successive blade rows. Moreover, by reducing the axial spacing, the stall pattern transition pace from multi-cell stall to single-cell stall can be shifted. And the compressor directly slips into single-cell stall at 21.0% CR axial spacing. By analyzing the pressure fluctuation closed to the surge line, it can be known that there exists an eigenfrequency where the amplitude of the oscillating pressure suddenly and dramatically increases as the compressor runs close to the surge line and this pressure disturbance is relevant to the compressor instability.
基金Supported by the National Natural Science Foundation of China under Grant No.50776021
文摘In order to study the effects of wet compression on a transonic compressor,a full 3-D steady numerical simulation was carried out under varying conditions.Different injected water flow rates and droplet diameters were considered.The effect of wet compression on the shock,separated flow,pressure ratio,and efficiency was investigated.Additionally,the effect of wet compression on the tip clearance when the compressor runs in the near-stall and stall situations was emphasized.Analysis of the results shows that the range of stable operation is extended,and that the pressure ratio and inlet air flow rate are also increased at the near-stall point.In addition,it seems that there is an optimum size of the droplet diameter.
基金supported by a Grant-in-Aid for Scientific Research through grant number 20560171 from Japanese Society for the Promotion of Science
文摘Unsteady behaviors as well as unsteady cascade flow fields of a single-stage axial flow compressor were experi- mentally investigated by detail measurements of unsteady performance characteristics and casing wall pressure and internal flow velocity fluctuations. The main feature of the test compressor is a capacity tank connected di- rectly to the compressor outlet in series through slits and a concentric duplex pipe, and also jet nozzles in order to inject compressed air toward the rotor tip region. Research attention is focused on the post-stall characteristics of surge and rotating stall which occur simultaneously. When the compressor was connected to the capacity tank, surge was generated with rotating stall in accordance with the capacitance increment of whole compressor system The surge behavior changed irregularly with throttling valve installed behind the compressor, and several types of surge cycles were observed. In addition, the surge cycle changed by jet injection to the rotor tip region. The re- suits suggested that the blockages of the cascade flow which were generated by a stall cell play an important role in deciding the surge behaviors.
