Spanwise Mixing in Multistage Axial Flow Compressors: Part II—Throughflow Calculations Including Mixing

1986 ◽  
Vol 108 (1) ◽  
pp. 10-16 ◽  
Author(s):  
S. J. Gallimore
Keyword(s):  
Diffusion Process ◽  
Turbulent Diffusion ◽  
Physical Mechanism ◽  
Axial Flow ◽  
Important Influence ◽  
Axial Compressors ◽  
Streamline Curvature ◽  
Loss Distributions ◽  
Total Temperature ◽  
Flow Through

The important influence of spanwise mixing on the flow through multistage axial compressors has been investigated by incorporating the effect into an axisymmetric streamline curvature throughflow program. The mixing was modeled as a turbulent diffusion process based on the experimental observations reported in Part I of this paper, which showed that this was the dominant physical mechanism. The inclusion of the mixing was found to be crucial in accurately predicting spanwise variations of exit total temperature in multistage machines. The effect of mixing on loss distributions inferred from measurements was found to be significant so that upstream loss sources could only be determined from downstream distributions when the effect of mixing was included.

scholarly journals Spanwise Transport in Axial-Flow Turbines: Part 2 — Throughflow Calculations Including Spanwise Transport

1993 ◽  
Author(s):  
K. L. Lewis
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Low Aspect Ratio ◽  
Loss Distributions ◽  
Diffusive Term ◽  
Two Stages ◽  
Throughflow Model

In Part 1 of this paper, a repeating stage condition was shown to occur in two low aspect ratio turbines, after typically two stages. Both turbulent diffusion and convective mechanisms were responsible for spanwise transport. In this part, two scaling expressions are determined that account for the influence of these mechanisms in effecting spanwise transport. These are incorporated into a throughflow model using a diffusive term. The inclusion of spanwise transport allows the use of more realistic loss distributions by the designer as input to the throughflow model and therefore focuses attention on areas where losses are generated. In addition, modelling of spanwise transport is shown to be crucial in predicting the attenuation of a temperature profile through a turbine.

Calculation of Fluid Motion in Axial Flow Turbomachines

1968 ◽  
Author(s):  
D. J. L. Smith ◽  
J. F. Barnes
Keyword(s):  
Experimental Work ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Streamline Curvature ◽  
Through Flow ◽  
Loss Distributions ◽  
The Matrix ◽  
Made In

In the last few years considerable progress has been made in calculating the three-dimensional flows through turbomachines. The two methods which appear to be widely used are what have come to be known as the “Streamline Curvature” and the “Matrix Through Flow” methods. At the National Gas Turbine Establishment, these advanced methods have been applied to existing turbomachines and this paper presents some of the calculated and experimental results for four axial flow machines. By making use of fairly simple loss distributions it has been found that these methods can assist towards the understanding of observed phenomena and, in the case of the axial compressor, they offer some prospect of being able to calculate the onset of surge. Also included is a brief report of work in progress to generate a computer program for the solution of the compressible velocity distribution around the surfaces of turbomachine blades, together with an indication of possible future experimental work.

A Comparison of the Streamline Throughflow and Streamline Curvature Methods for Axial Turbomachinery

1998 ◽  
Author(s):  
Anthony J. Gannon ◽  
Theodor W. von Backström
Keyword(s):  
Stream Function ◽  
Compressible Flows ◽  
Swirling Flow ◽  
Axial Flow ◽  
Computer Time ◽  
Computational Grids ◽  
Test Cases ◽  
Streamline Curvature ◽  
Order Of Magnitude ◽  
Flow Through

The axial flow turbo machinery throughflow equation states that radial gradients of rothalpy, entropy and moment of momentum affect the conservation of tangential vorticity. The streamline throughflow method (STFM) transforms this equation, expressed in terms of stream function in a radial-axial co-ordinate system, to an equation for streamline radial position in a stream function-axial co-ordinate system. The paper assesses the accuracy and efficiency of the STFM relative to the streamline curvature method (SCM) by comparing streamline positions and velocity profiles to analytical results. Test cases include flow through a single actuator disc, flow through twin actuator discs using a coarse computational grid, compressible flows through an almost choked nozzle, through single and twin actuator discs, and swirling flow using sloped stations. Results from the STFM and SCM agreed about equally well with analytical solutions for the same number of streamlines. The STFM, however, was much more tolerant of distorted computational grids and used an order of magnitude less computer time to converge. The test cases show that the STFM is suitable for annuli with large variations in hub and tip radius, for highly swirling and compressible flow, and is more robust and converges faster than the SCM. To demonstrate the practical applicability of the STFM a multistage compressor was simulated and STFM results compared with experiment.

Performance of Two Transonic Axial Compressor Rotors Incorporating Inlet Counterswirl

1987 ◽  
Vol 109 (1) ◽  
pp. 142-148 ◽  
Author(s):  
C. H. Law ◽  
A. J. Wennerstrom
Keyword(s):  
Static Pressure ◽  
Axial Compressor ◽  
Axial Flow ◽  
Leading Edge ◽  
Axial Compressors ◽  
Streamline Curvature ◽  
Static Pressure Distribution ◽  
Pressure Distributions ◽  
Blade Section ◽  
Flow Compressor

A single-stage axial-flow compressor which incorporates rotor inlet counterswirl to improve stage performance is discussed. Results for two rotor configurations are presented, including design and experimental test data. In this compressor design, inlet guide vanes were used to add counterswirl to the inlet of the rotor. The magnitude of the counterswirl was radially distributed to maximize the overall stage efficiency by minimizing the rotor combined losses (diffusion losses and shock losses). The shock losses were minimized by simultaneously optimizing the rotor blade section geometry, through-blade static pressure distribution, and leading edge aerodynamic/geometric shock sweep angles. Results from both the design and experimental performance analyses are presented and comparisons are made between the experimental data and the analyses and between the performance of both rotor designs. The computation of the flow field for both rotor designs and for the analysis of both tests was performed in an identical fashion using an axisymmetric, streamline-curvature-type code. Results presented include tip section blade-to-blade static pressure distributions and rotor through-blade and exit distributions of various aerodynamic parameters. The performance of this compressor stage represents a significant improvement in axial compressor performance compared to previous attempts to use rotor inlet counterswirl and to current, more conventional, state-of-the-art axial compressors operating under similar conditions.

Spanwise Transport in Axial-Flow Turbines: Part 2—Throughflow Calculations Including Spanwise Transport

1994 ◽  
Vol 116 (2) ◽  
pp. 187-193 ◽  
Author(s):  
K. L. Lewis
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Low Aspect Ratio ◽  
Loss Distributions ◽  
Diffusive Term ◽  
Two Stages ◽  
Throughflow Model

In Part 1 of this paper, a repeating stage condition was shown to occur in two low aspect ratio turbines, typically after two stages. Both turbulent diffusion and convective mechanisms were responsible for spanwise transport. In this part, two scaling expressions are determined that account for the influence of these mechanisms in effecting spanwise transport. These are incorporated into a throughflow model using a diffusive term. The inclusion of spanwise transport allows the use of more realistic loss distributions by the designer as input to the throughflow model and therefore focuses attention on areas where losses are generated. In addition, modeling of spanwise transport is shown to be crucial in predicting the attenuation of a temperature profile through a turbine.

Throughflow Calculations for Transonic Axial Flow Turbines

1978 ◽  
Vol 100 (2) ◽  
pp. 212-218 ◽  
Author(s):  
J. D. Denton
Keyword(s):  
Transonic Flow ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Steam Turbines ◽  
Flow Measurements ◽  
High Pressure Ratio ◽  
Streamline Curvature ◽  
Flow Through ◽  
Good Agreement

The development of a streamline curvature throughflow program to predict the flow through the low pressure stages of large steam turbines is described. The program can also be used for gas turbines. Difficulties encountered in dealing with transonic flow and multiple high pressure ratio stages are discussed. Comparisons of the predictions of the program with flow measurements in steam and gas turbines show reasonably good agreement with most of the discrepancies being attributable to errors in the empirical data input to the program.

scholarly journals Performance of Two Transonic Axial Compressor Rotors Incorporating Inlet Counterswirl

1986 ◽  
Author(s):  
C. Herbert Law ◽  
Arthur J. Wennerstrom
Keyword(s):  
Static Pressure ◽  
Axial Compressor ◽  
Axial Flow ◽  
Leading Edge ◽  
Axial Compressors ◽  
Streamline Curvature ◽  
Static Pressure Distribution ◽  
Pressure Distributions ◽  
Blade Section ◽  
Flow Compressor

A single-stage axial-flow compressor which incorporates rotor inlet counterswirl to improve stage performance is discussed. Results for two rotor configurations are presented, including design and experimental test data. In this compressor design, inlet guide vanes were used to add counterswirl to the inlet of the rotor. The magnitude of the counterswirl was radially distributed to maximize the overall stage efficiency by minimizing the rotor combined losses (diffusion losses and shock losses). The shock losses were minimized by simultaneously optimizing the rotor blade section geometry, through-blade static pressure distribution, and leading edge aerodynamic/geometric shock sweep angles. Results from both the design and experimental performance analyses are presented and comparisons are made between the experimental data and the analyses and between the performances of both rotor designs. The computation of the flow field for both rotor designs and for the analysis of both tests was performed in an identical fashion using an axisymmetric, streamline-curvature-type code. Results presented include tip section blade-to-blade static pressure distributions and rotor through-blade and exit distributions of various aerodynamic parameters. The performance of this compressor stage represents a significant improvement in axial compressor performance compared to previous attempts to use rotor inlet counterswirl and to current, more conventional, state-of-the-art axial compressors operating under similar conditions.

Flow through axial-flow-turbomachinery blading

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Flow Velocity ◽  
Compressible Flow ◽  
Dimensional Analysis ◽  
Incompressible Flow ◽  
Compressible Fluid ◽  
Axial Flow ◽  
Linear Cascade ◽  
Dimensional Parameters ◽  
Flow Through

This chapter is concerned primarily with the flow of a compressible fluid through stationary and moving blading, for the most part using the analysis introduced in Chapter 11. The principles of dimensional analysis are applied to determine the appropriate non-dimensional parameters to characterise the performance of a turbomachine. The analysis of incompressible flow through a linear cascade of aerofoil-like blades is followed by the analysis of compressible flow. Velocity triangles for flow relative to blades, and Euler’s turbomachinery equation, are introduced to analyse flow through a rotor. The concepts introduced are applied to the analysis of an axial-turbomachine stage comprising a stator and a rotor, which applies to either a compressor or a turbine.

Three-Dimensional Flows and Loss Reduction in Axial Compressors

1987 ◽  
Vol 109 (3) ◽  
pp. 354-361 ◽  
Author(s):  
Y. Dong ◽  
S. J. Gallimore ◽  
H. P. Hodson
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Tracer Gas ◽  
Suction Surface ◽  
Axial Compressors ◽  
Small Clearance ◽  
Oil Flow ◽  
Stator Blade ◽  
Flow Compressor

Measurements have been performed in a low-speed high-reaction single-stage axial compressor. Data obtained within and downstream of the rotor, when correlated with the results of other investigations, provide a link between the existence of suction surface–hub corner separations, their associated loss mechanisms, and blade loading. Within the stator, it has been shown that introducing a small clearance between the stator blade and the stationary hub increases the efficiency of the stator compared to the case with no clearance. Oil flow visualizaton indicated that the leakage reduced the extensive suction surface–hub corner separation that would otherwise exist. A tracer gas experiment showed that the large radial shifts of the surface streamlines indicated by the oil flow technique were only present close to the blade. The investigation demonstrates the possible advantages of including hub clearance in axial flow compressor stator blade rows.

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