Application of the Multistage Axial-Flow Compressor Time-Dependent Mathematical Modeling Technique to the TF41-A-1 Modified (Block 76) Compressor

1979 ◽  
Author(s):  
C. E. Chamblee
Keyword(s):  
Mathematical Modeling ◽  
Axial Flow ◽  
Time Dependent ◽  
Modeling Technique ◽  
Axial Flow Compressor ◽  
Modified Block ◽  
Flow Compressor ◽  
Mathematical Modeling Technique

Flow Fields in an Axial Flow Compressor During Four-Quadrant Operation

2013 ◽  
Author(s):  
Andrew Gill ◽  
Theodor W. von Backström ◽  
Thomas M. Harms ◽  
Dwain Dunn
Keyword(s):  
Flow Direction ◽  
Tangential Velocity ◽  
Axial Compressor ◽  
Axial Flow ◽  
Pressure Rise ◽  
Flow Fields ◽  
Time Dependent ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

It has been shown in previous investigations that when all combinations of both positive and negative direction of rotation and flow direction are allowed in operating a multistage axial flow compressor, the operating point may be in any of the four quadrants of the pressure rise versus flow characteristic. The present paper is the first discussion of the flow field of all possible modes of operation of an axial flow compressor. During the present study interstage time dependent hot film velocity measurements and five hole pneumatic probe measurements were combined with steady and time dependent CFD solutions to investigate the flow fields in the three-stage axial compressor. Results are presented in terms of mean-line velocity triangles, mean stream surface plots, mid-span radial velocity contours right through the compressor, rotor-downstream radial distributions of axial and tangential velocity, stator-downstream axial velocity contours and mid-span entropy contours through the compressor. Main flow features are pointed out and discussed. The study was instigated in an effort to understand possible accident scenarios in a three-shaft closed cycle nuclear powered helium gas turbine.

Growth of a Perturbation in an Axial Flow Compressor

1979 ◽  
Vol 101 (1) ◽  
pp. 87-94 ◽  
Author(s):  
J. Fabri
Keyword(s):  
Angular Velocity ◽  
Initial Perturbation ◽  
Axial Compressor ◽  
Axial Flow ◽  
Time Dependent ◽  
Perturbation Amplitude ◽  
Axial Flow Compressor ◽  
Linearized Theory ◽  
Flow Compressor ◽  
Multistage Axial Compressor

A time-dependent linearized approach is used to predict the amplification or the decay of an initial perturbation in the multistage axial compressor of high hub-to-tip ratio. This analysis shows that for unstalled flow regimes the change in perturbation amplitude remains limited. The linearized theory remains valid until the stall limit. It is shown that, near this limit, peripheral propagation of an induced perturbation takes place at an angular velocity close to one-half of rotor angular velocity. However in most cases this perturbation has a limited amplitude.

Reverse Flow Turbine-Like Operation of an Axial Flow Compressor

2012 ◽  
Author(s):  
A. Gill ◽  
T. W. von Backström ◽  
T. M. Harms
Keyword(s):  
Reverse Flow ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Harmonic Approximation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Time Dependent ◽  
Navier Stokes ◽  
Axial Flow Compressor ◽  
Flow Compressor

This article describes an experimental investigation of the flow structures occurring in an axial flow compressor during second quadrant operation for reversed rotor rotation in the incompressible flow regime. In second quadrant operation, the flow direction is reversed, but the pressure is lower at the compressor inlet than at the outlet. The compressor thus acts as an axial flow turbine. A three stage axial flow compressor, with a mass flow rate of 2.7 kg/s and a pressure ratio of 1.022 was investigated. The design rotor tip Mach number is 0.2. Three operational points within the second quadrant were investigated, at flow coefficients of −0.482, −0.553 and −0.843. A five hole conical probe and a 50 micron diameter inclined hot film anemometer were used in this investigation. Radial traverses downstream of rotor rows and a time-dependent area traverse downstream of the first stage stator were performed. Three-dimensional time-dependent numerical Navier-Stokes solutions using the non-linear harmonic approximation for single blade passages in each blade row for each of the cases are compared with experimental work. The compressor has already been show to be capable of attaining relatively high turbine efficiency (76%) when operating in this mode. Examination of the flow field shows that little to no flow separation occurs on the rotor or stator blades. The wakes of all blades are found to be thin and sharp, and the area between wakes is large and approximately uniform. Numerical results agree relatively well with experimental results.

The Flow Field Within an Axial Flow Compressor at Extremely High Flow Coefficients

2010 ◽  
Author(s):  
A. Gill ◽  
T. W. von Backstro¨m ◽  
T. M. Harms
Keyword(s):  
Steady State ◽  
Pressure Ratio ◽  
Harmonic Approximation ◽  
Axial Flow ◽  
Pressure Rise ◽  
Flow Coefficient ◽  
Time Dependent ◽  
Fourth Quadrant ◽  
Axial Flow Compressor ◽  
Flow Compressor

This article describes an experimental investigation of the flow structures occurring in a three-stage axial flow compressor during fourth quadrant operation in the incompressible flow regime. In fourth quadrant operation, the flow coefficient exceeds the design value to such a degree that the pressure difference between the compressor inlet and outlet becomes negative, and the compressor acts as a badly designed turbine. The pressure rise characteristic curve thus extends into the fourth quadrant of the compressor map. A three stage axial flow compressor, with a mass flow rate of 2.7 kg/s and a pressure ratio of 1.022 was investigated. The design rotor tip Mach number is 0.2. Three operational points within the fourth quadrant were investigated, at flow coefficients of 0.665, 0.747 and 1.024. A five hole conical probe and a 50 μm diameter inclined hot film anemometer were used in this investigation. Radial traverses downstream of rotor rows and a time-dependent area traverse downstream of the first stage stator were performed. Three-dimensional steady-state and time-dependent numerical Navier-Stokes solutions for single blade passages in each blade row for each of the cases are compared with experimental work. Large wakes were observed downstream of all stator rows, as a result of significant flow separation on stator blades. The area fraction of the flow passage affected by the wakes increases as the flow coefficient increases. Flow through rotor blade-passages is heavily affected by the blade position relative to upstream stator wakes. Due to the effect of the stator wakes on downstream blading, time-dependent solutions using the nonlinear harmonic approximation were found to agree better with experimental results than steady-state solutions using mixing planes between blade rows.

Flow Fields in an Axial Flow Compressor During Four-Quadrant Operation

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Andrew Gill ◽  
Theodor W. Von Backström ◽  
Thomas M. Harms
Keyword(s):  
Flow Direction ◽  
Tangential Velocity ◽  
Axial Compressor ◽  
Axial Flow ◽  
Pressure Rise ◽  
Flow Fields ◽  
Time Dependent ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

It has been shown in previous investigations that when all combinations of both positive and negative direction of rotation and flow direction are allowed in operating a multistage axial flow compressor, the operating point may be in any of the four quadrants of the pressure rise versus flow characteristic. The present paper is the first discussion of the flow field of all possible modes of operation of an axial flow compressor. During the present study interstage time dependent hot film velocity measurements and five hole pneumatic probe measurements were combined with steady and time dependent CFD solutions to investigate the flow fields in the three-stage axial compressor. Results are presented in terms of mean-line velocity triangles, mean stream surface plots, midspan radial velocity contours right through the compressor, rotor-downstream radial distributions of axial and tangential velocity, stator-downstream axial velocity contours and midspan entropy contours through the compressor. Main flow features are pointed out and discussed. The study was instigated in an effort to understand possible accident scenarios in a three-shaft closed cycle nuclear powered helium gas turbine.

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