Reynolds Number Effects in Axial Compressors

1968 ◽  
Vol 90 (2) ◽  
pp. 149-156 ◽  
Author(s):  
A. B. Wassell
Keyword(s):  
Reynolds Number ◽  
Total Pressure ◽  
Performance Parameters ◽  
Axial Compressors ◽  
Flow Reynolds Number ◽  
Reynolds Number Effects ◽  
Compressor Performance ◽  
Flow Changes ◽  
Design Speed ◽  
Main Compressor

The influence of variations in flow Reynolds number on the performance of axial compressors has been studied (changes in Reynolds number being, for the most part, achieved by changes in the inlet total pressure at or near the design speed). The measured results, so achieved, have been correlated to show how the main compressor performance parameters vary with Reynolds number. Reference has been made to cascade data to assist in choosing the form of the correlation, which is essentially empirical. A good correlation of the measured performance changes on component tests has been obtained. The method described, therefore, appears to be satisfactory for predicting trends for project assessments and avoids considering the detailed flow changes that occur within the machine as the Reynolds number is varied.

A New Appraisal of Reynolds Number Effects on Centrifugal Compressor Performance

1979 ◽  
Vol 101 (3) ◽  
pp. 384-392 ◽  
Author(s):  
F. J. Wiesner
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Performance Test ◽  
Flow Coefficient ◽  
Performance Parameters ◽  
Empirical Methods ◽  
Reynolds Number Effects ◽  
Significant Performance ◽  
Compressor Performance ◽  
Overall Performance

This paper summarizes the results of an investigation into the effects of Reynolds number on the performance of centrifugal compressor stages, using a computer program for the detailed prediction of component and overall performance characteristics. This investigation included wide variation of stage geometries, speeds, and fluid conditions, resulting in diffuser inlet absolute Reynolds number variations over the range from 5 × 102 to 5 × 108. The computer results indicate that variations in Reynolds number and in relative roughness will produce variations in all significant performance parameters: the flow coefficient, the work coefficient, and the efficiency. Correlations of these results with various sources of test data on single and multistage centrifugal compressors produce very satisfactory comparisons. As a result of this study, improved empirical methods are recommended for making practical adjustments of compressor performance with variation in Reynolds number. These recommendations should be taken into account in the modernization of all centrifugal compressor performance test codes such as those formulated by ASME and ISO.

Effect of Backward Sweep on Aerodynamic Performance of a 1.5-Stage Highly Loaded Axial Compressor

2020 ◽  
Author(s):  
Song Huang ◽  
Chuangxin Zhou ◽  
Chengwu Yang ◽  
Shengfeng Zhao ◽  
Mingyang Wang ◽  
...  
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Blade Loading ◽  
Stall Margin ◽  
Axial Compressors ◽  
Design Speed ◽  
Total Pressure Ratio ◽  
Highly Loaded

Abstract As a degree of freedom in the three-dimensional blade design of axial compressors, the sweep technique significantly affects the aerodynamic performance of axial compressors. In this paper, the effects of backward sweep rotor configurations on the aerodynamic performance of a 1.5-stage highly loaded axial compressor at different rotational design speeds are studied by numerical simulation. The aim of this work is to improve understanding of the flow mechanism of backward sweep on the aerodynamic performance of a highly loaded axial compressor. A commercial CFD package is employed for flow simulations and analysis. The study found that at the design rotational speed, compared with baseline, backward sweep rotor configurations reduce the blade loading near the leading edge but slightly increases the blade loading near the trailing edge in the hub region. As the degree of backward sweep increases, the stall margin of the 1.5-stage axial compressor increase first and then decrease. Among different backward sweep rotor configurations, the 10% backward sweep rotor configuration has the highest stall margin, which is about 2.5% higher than that of baseline. This is due to the change of downstream stator incidence, which improves flow capacity near the hub region. At 80% rotational design speed, backward sweep rotor configurations improve stall margin and total pressure ratio of the compressor. It’s mainly due to the decreases of the rotor incidence near the middle span, which results in the decreases of separation on the suction surface. At 60% rotational design speed, detached shock disappears. Backward sweep rotor configurations deteriorate stall margin of the compressor, but increase total pressure ratio and adiabatic efficiency when the flow rate is lower than that at peak efficiency condition. Therefore, it’s necessary to consider the flow field structure of axial compressors at whole operating conditions in the design process and use the design freedom of sweep to improve the aerodynamic performance.

Effects of Reynolds Number on Performance of Highly Loaded Multi-Stage Axial Compressors

2020 ◽  
Author(s):  
Xiaoshi Zhang
Keyword(s):  
Reynolds Number ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Correlation Method ◽  
Single Stage ◽  
Test Results ◽  
Low Speed ◽  
Compressor Performance ◽  
Design Speed ◽  
Highly Loaded

Abstract The influence of Reynolds number on performance of a highly loaded 10-stage axial compressor has been experimentally investigated. The experiment was performed by applying different inlet Reynolds numbers at several operating speeds. Reynolds number variation was achieved by throttling the inlet pressure. Both compressor total aerodynamic characteristics and detailed single stage performance were measured and analyzed. Test results show that all the compressor performance parameters including efficiency, mass flow and pressure ratio are reduced by decreasing Reynolds number. And the influence is higher at lower operating speed. Regarding to single stage characteristics, stage matching is less affected by Reynolds number at design speed, while all single stage chics are changed at low speed. The correlation between Reynolds number and compressor performance was obtained. Then the Wassell semi-empirical correlation method was applied to predict the Reynolds number influences for the same compressor. Comparison was made between experimental results and calculating results based on Wassell correlation. Results indicate that Wassell correlation is reliable for predicting trends. Wassell correlation works well for efficiency at design speed, but providing calculating inaccuracy at low speed. For mass flow correlation, Wassell correlation overestimated the influence of Reynolds number. Test results from this compressor are added to Wassell correlation curve, that provide reference for modern design application.

Small Turbomachinery Compressor and Fan Aerodynamics

1973 ◽  
Vol 95 (3) ◽  
pp. 251-256 ◽  
Author(s):  
R. C. Pampreen
Keyword(s):  
Reynolds Number ◽  
Test Results ◽  
Centrifugal Compressors ◽  
Reynolds Number Effects ◽  
Compressor Performance ◽  
Compressor Efficiency

This paper discusses aerodynamic considerations in the design of small turbomachinery axial and centrifugal compressors and fans. Test results are presented to show the effect of scaling on compressor performance. Correlations are presented which relate compressor efficiency to Reynolds Number and clearance. It is shown that clearance effects are more prominent when scaling designs, and Reynolds Number effects are more prominent as density is lowered.

Similarity Solution for Heat Convection From a Porous Rotating Disk in a Flow Field

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Abdullah Abbas Kendoush
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flow Field ◽  
Similarity Solution ◽  
Energy Equation ◽  
Rotating Disk ◽  
Porous Disk ◽  
Transfer Rates ◽  
Flow Reynolds Number ◽  
Reynolds Number Effects

A mathematical method is described for the analytical solution of the convective heat transfer rates from a rotating isothermal and porous disk in a uniform flow field. By applying the appropriate velocity component of the fluid in the energy equation, a similarity solution was derived showing an increase in the rates of heat transfer with increasing rotational Reynolds number and with decreasing flow Reynolds number. Effects of natural convection and viscous dissipation were assumed negligible.

Sign in / Sign up

Export Citation Format

Share Document