The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total p...The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total pressure loss. Experiments and numerical simulations, keeping the inlet March number of prediffuser constant ( Ma =0 20), are carried out to obtain the regularity of the total pressure loss. It varies with the relative dump gap ( δ =1 2～3 0)by changing the position of prediffuser and combustor liner, respectively. Research shows that there exists the minimum total pressure loss ( σ *=1 6%～1 75%) when relative dump gap δ is about 1 8.展开更多
Influences of tip clearance on the tip flow and associated loss mechanism in a contra-rotating axial flow fan hasbeen studied in the paper, based on three dimensional numerical results. The results with different tip ...Influences of tip clearance on the tip flow and associated loss mechanism in a contra-rotating axial flow fan hasbeen studied in the paper, based on three dimensional numerical results. The results with different tip clearanceare compared in terms of stage efficiency, relative total pressure loss coefficient, flow angle. It is found that theefficiency of the contra-rotating fan changes almost linearly with increment of the tip clearance, however, efficiencyof the rear rotor is observed to decrease more dramatically than that of the forward rotor given same tipclearance variation. The analysis on the flow structure indicates that the tip region flow field is qualitatively similarin both rotors. However, with the same clearance value, the leakage flow in the rear rotor is effected by a tipleakage vortex of greater intensity caused by relative loading levels and the inter rotor interaction.展开更多
An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with thre...An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The fiowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.展开更多
文摘The dump diffuser is an important component in advanced annular combustor, and its performance affects greatly the fluid field and pressure loss of the combustor. This paper presents the characteristics of the total pressure loss. Experiments and numerical simulations, keeping the inlet March number of prediffuser constant ( Ma =0 20), are carried out to obtain the regularity of the total pressure loss. It varies with the relative dump gap ( δ =1 2～3 0)by changing the position of prediffuser and combustor liner, respectively. Research shows that there exists the minimum total pressure loss ( σ *=1 6%～1 75%) when relative dump gap δ is about 1 8.
文摘Influences of tip clearance on the tip flow and associated loss mechanism in a contra-rotating axial flow fan hasbeen studied in the paper, based on three dimensional numerical results. The results with different tip clearanceare compared in terms of stage efficiency, relative total pressure loss coefficient, flow angle. It is found that theefficiency of the contra-rotating fan changes almost linearly with increment of the tip clearance, however, efficiencyof the rear rotor is observed to decrease more dramatically than that of the forward rotor given same tipclearance variation. The analysis on the flow structure indicates that the tip region flow field is qualitatively similarin both rotors. However, with the same clearance value, the leakage flow in the rear rotor is effected by a tipleakage vortex of greater intensity caused by relative loading levels and the inter rotor interaction.
基金supported by the National Natural Science Foundation of China(No.51076018)the Fundamental Research Funds for the Central Universities(No.3132014041)Specialized Research Fund for the Doctoral Program of Higher Education
文摘An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The fiowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.
