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.

On the Evaluation of Reynolds Number and Relative Surface Roughness Effects on Centrifugal Compressor Performance Based on Systematic Experimental Investigations

1984 ◽  
Vol 106 (2) ◽  
pp. 489-498 ◽  
Author(s):  
H. Simon ◽  
A. Bu¨lska¨mper
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Performance Test ◽  
Flow Coefficient ◽  
Experimental Investigations ◽  
Design Calculation ◽  
Roughness Effects ◽  
Number Range ◽  
Compressor Performance

This paper summarizes the results of systematic investigations into the Reynolds number effects. It is based on performance map measurements carried out on a compressor test rig which was constructed primarily for this purpose. The measurements were performed for stages with different flow coefficients (0.004 ≦ φ1 ≦ 0.05), with different gases (air, nitrogen, helium, freon) and in the inlet pressure range 0.2 bar ≦ p1 ≦ 40 bar. By analogy with the turbulent flow in technically rough pipes, semi-empirical correlations are derived concerning the effects of the Reynolds number and the relative surface roughness on the characteristic performance parameters (efficiency, flow coefficient, head coefficient, work coefficient). For the detailed design calculation of individual stages, provision is made for the different effects on the hydraulic flow losses and the disk friction losses. Simplified correlations are given for the conversion of characteristics measured during thermodynamic performance tests. The correlations are applied to various single and multistage compressors, and the results compared with measured performance characteristics in the Reynolds number range 6 × 103 ≦ Ret ≦ 1.1 × 107. The good correspondence obtained forms the basis for recommending the application of these simplified relationships for the improvement of centrifugal compressor performance test codes (e.g. ASME PTC-10 and ISO TC 118).

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.

The Effects of Reynolds Number on the Efficiency of Centrifugal Compressor Stages

1985 ◽  
Vol 107 (2) ◽  
pp. 541-548 ◽  
Author(s):  
M. V. Casey
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Width Ratio ◽  
Empirical Methods ◽  
Empirical Coefficient ◽  
Impeller Outlet ◽  
Wide Range ◽  
Reynolds Number Effects ◽  
Work Input ◽  
New Form

An analysis of the friction losses in a centrifugal compressor stage is used to suggest a new form of correction equation for the effect of Reynolds number on efficiency. This equation relates the effect of Reynolds number to the surface roughness, the impeller outlet width ratio and the work input coefficient. Systematic tests on a wide range of compressor stages are used to calibrate the single empirical coefficient in the equation. Despite its simplicity this equation provides more accurate predictions of the Reynolds number effects than existing empirical methods.

Investigation on Effect of Curvilinear Element Blades on Centrifugal Impeller Performance

2017 ◽  
Author(s):  
Kiyotaka Hiradate ◽  
Hiromi Kobayashi ◽  
Takahiro Nishioka
Keyword(s):  
Centrifugal Compressor ◽  
Performance Test ◽  
Design Guidelines ◽  
Secondary Flows ◽  
Flow Coefficient ◽  
Numerical Calculations ◽  
Centrifugal Impeller ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Compressor Impeller

This study experimentally and numerically investigates the effect of application of curvilinear element blades to fully-shrouded centrifugal compressor impeller on the performance of centrifugal compressor stage. Design suction flow coefficient of compressor stage investigated in this study is 0.125. The design guidelines for the curvilinear element blades which had been previously developed was applied to line element blades of a reference conventional impeller and a new centrifugal compressor impeller with curvilinear element blades was designed. Numerical calculations and performance tests of two centrifugal compressor stages with the conventional impeller and the new one were conducted to investigate the effectiveness of application of the curvilinear element blades and compare the inner flowfield in details. Despite 0.5% deterioration of the impeller efficiency, it was confirmed from the performance test results that the compressor stage with the new impeller achieved 1.7% higher stage efficiency at the design point than that with the conventional one. Moreover, it was confirmed that the compressor stage with the new impeller achieved almost the same off-design performance as that of the conventional stage. From results of the numerical calculations and the experiments, it is considered that this efficiency improvement of the new stage was achieved by suppression of the secondary flows in the impeller due to application of negative tangential lean. The suppression of the secondary flows in the impeller achieved uniformalized flow distribution at the impeller outlet and increased the static pressure recovery coefficient in the vaneless diffuser. As a result, it is thought that the total pressure loss was reduced downstream of the vaneless diffuser outlet in the new stage.

Reynolds Number and Roughness Effects on Turbocompressor Performance: Numerical Calculations and Measurement Data Evaluation

2020 ◽  
Author(s):  
Fabian Dietmann ◽  
Michael Casey ◽  
Damian M. Vogt
Keyword(s):  
Reynolds Number ◽  
Measurement Data ◽  
Theoretical Models ◽  
Design Flow ◽  
Flow Coefficient ◽  
Low Flow ◽  
Roughness Effects ◽  
Flow Channels ◽  
Compressor Performance ◽  
Low Flow Coefficient

Abstract Further validation of an analytic method to calculate the influence of changes in Reynolds number, machine size and roughness on the performance of axial and radial turbocompressors is presented. The correlation uses a dissipation coefficient as a basis for scaling the losses with changes in relative roughness and Reynolds number. The original correlation from Dietmann and Casey [6] is based on experimental data and theoretical models. Evaluations of five numerically calculated compressor stages at different flow coefficients are presented to support the trends of the correlation. It is shown that the sensitivity of the compressor performance to Reynolds and roughness effects is highest for low flow coefficient radial stages and steadily decreases as the design flow coefficient of the stage and the hydraulic diameter of the flow channels increases.

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