A similitude method to model the tip clearance flow in a high-speed compressor with a low-speed model is presented in this paper.The first step of this method is the derivation of similarity criteria for tip clearance...A similitude method to model the tip clearance flow in a high-speed compressor with a low-speed model is presented in this paper.The first step of this method is the derivation of similarity criteria for tip clearance flow,on the basis of an inviscid model of tip clearance flow.The aerodynamic parameters needed for the model design are then obtained from a numerical simulation of the target high-speed compressor rotor.According to the aerodynamic and geometric parameters of the target compressor rotor,a large-scale low-speed rotor blade is designed with an inverse blade design program.In order to validate the similitude method,the features of tip clearance flow in the low-speed model compressor are compared with the ones in the high-speed compressor at both design and small flow rate points.It is found that not only the trajectory of the tip leakage vortex but also the interface between the tip leakage flow and the incoming main flow in the high-speed compressor match well with that of its low speed model.These results validate the effectiveness of the similitude method for the tip clearance flow proposed in this paper.展开更多
Extensive numerical investigations of the performance and flow structure in an unshrouded tandem-bladed centrifugal compressor are presented in comparison to a conventional compressor.Stage characteristics are explore...Extensive numerical investigations of the performance and flow structure in an unshrouded tandem-bladed centrifugal compressor are presented in comparison to a conventional compressor.Stage characteristics are explored for various tip clearance levels,axial spacings and circumferential clockings.Conventional impeller was modified to tandem-bladed design with no modifications in backsweep angle,meridional gas passage and camber distributions in order to have a true comparison with conventional design.Performance degradation is observed for both the conventional and tandem designs with increase in tip clearance.Linear-equation models for correlating stage characteristics with tip clearance are proposed.Comparing two designs,it is clearly evident that the conventional design shows better performance at moderate flow rates.However;near choke flow,tandem design gives better results primarily because of the increase in throat area.Surge point flow rate also seems to drop for tandem compressor resulting in increased range of operation.展开更多
基金supported by National Natural Science Foundation of China(No.51206164,No.51106153,No.51236001)Chinese Academy of Sciences Visiting Professorship for Senior International Scientists Grant No.2001T2G01
文摘A similitude method to model the tip clearance flow in a high-speed compressor with a low-speed model is presented in this paper.The first step of this method is the derivation of similarity criteria for tip clearance flow,on the basis of an inviscid model of tip clearance flow.The aerodynamic parameters needed for the model design are then obtained from a numerical simulation of the target high-speed compressor rotor.According to the aerodynamic and geometric parameters of the target compressor rotor,a large-scale low-speed rotor blade is designed with an inverse blade design program.In order to validate the similitude method,the features of tip clearance flow in the low-speed model compressor are compared with the ones in the high-speed compressor at both design and small flow rate points.It is found that not only the trajectory of the tip leakage vortex but also the interface between the tip leakage flow and the incoming main flow in the high-speed compressor match well with that of its low speed model.These results validate the effectiveness of the similitude method for the tip clearance flow proposed in this paper.
基金the Deanship of Scientific Research,Research Center of College of Engineering, King Saud University for the financial support
文摘Extensive numerical investigations of the performance and flow structure in an unshrouded tandem-bladed centrifugal compressor are presented in comparison to a conventional compressor.Stage characteristics are explored for various tip clearance levels,axial spacings and circumferential clockings.Conventional impeller was modified to tandem-bladed design with no modifications in backsweep angle,meridional gas passage and camber distributions in order to have a true comparison with conventional design.Performance degradation is observed for both the conventional and tandem designs with increase in tip clearance.Linear-equation models for correlating stage characteristics with tip clearance are proposed.Comparing two designs,it is clearly evident that the conventional design shows better performance at moderate flow rates.However;near choke flow,tandem design gives better results primarily because of the increase in throat area.Surge point flow rate also seems to drop for tandem compressor resulting in increased range of operation.
