Mixing in Axial Flow Compressors: Part I — Test Facilities and Measurements in a Four-Stage Compressor

1990 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty

The mechanism of mixing in axial flow compressors has been investigated in two low speed machines. For reasons of length this is described in two parts. Results in a 4-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.

1991 ◽  
Vol 113 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty

The mechanism of mixing in axial flow compressors has been investigated in two low-speed machines. For reasons of length this is described in two parts. Results in a four-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single-stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.


1994 ◽  
Author(s):  
K. Imanari

A theoretical model is proposed for the spanwise mixing caused by periodic incoming wakes in the context of turbulent diffusion in axial-flow compressors prior to repeating-stage conditions. The model was used to predict the spanwise mixing coefficients across a stator of a single-stage compressor without IGVs. The correctness of the theory was demonstrated by the results that the predicted values were in good agreement with the associated experimental data.


Author(s):  
Horst Saathoff ◽  
Udo Stark

The paper describes an investigation of the overtip end-wall flow in a single–stage axial–flow low–speed compressor utilizing an oil flow technique and a periodic multisampling pressure measurement technique. Representative oil flow pictures and ensemble averaged casingwall pressure distributions with standard deviations — supplemented by selected endwall oil flow pictures from a corresponding 2D compressor cascade — are shown and carefully analysed. The results enable the key features of the overtip endwall flow to be identified and changes with flow rate — or inlet angle — to be determined.


Author(s):  
Yan De-You

This paper provides a method of modelling the axial-flow compressors in the low speed starting regime of an engine from windmilling to idling. A structural formula for the model is established by means of reference (1). A method of step-by-step regression is provided by the author for determining the coefficient matrices of the structural formulae. Excellent agreement was obtained between the computational and experimental results.


2000 ◽  
Vol 123 (3) ◽  
pp. 483-489 ◽  
Author(s):  
Jens Friedrichs ◽  
Sven Baumgarten ◽  
Gu¨nter Kosyna ◽  
Udo Stark

The paper describes an experimental investigation of the stator hub and blade flow in two different stators of a highly loaded single-stage axial-flow low-speed compressor. The first stator (A) is a conventional design with blades of rectangular planform. The second stator (K) is an unconventional, more advanced design with blades of a special planform, characterized by an aft-swept leading edge with increasing sweep angle toward hub and casing. The experimental results show that stator K exhibits a much better hub performance than stator A, finally leading to a better overall performance of stage K compared to stage A. The better hub performance of stator K is, primarily, the result of a planform effect of the newly introduced blades with an aft-swept leading edge and the aerodynamics of an aft-swept wing.


1997 ◽  
Vol 119 (4) ◽  
pp. 714-722 ◽  
Author(s):  
G. J. Hendricks ◽  
J. S. Sabnis ◽  
M. R. Feulner

A nonlinear, two-dimensional, compressible dynamic model has been developed to study rotating stall/surge inception and development in high-speed, multistage, axial flow compressors. The flow dynamics are represented by the unsteady Euler equations, solved in each interblade row gap and inlet and exit ducts as two-dimensional domains, and in each blade passage as a one-dimensional domain. The resulting equations are solved on a computational grid. The boundary conditions between domains are represented by ideal turning coupled with empirical loss and deviation correlations. Results are presented comparing model simulations to instability inception data of an eleven stage, high-pressure-ratio compressor operating at both part and full power, and the results analyzed in the context of a linear modal analysis.


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