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).

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.

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.

In-Stall Compressor Performance and the Effects of Reynolds Number

2021 ◽  
Author(s):  
Jack Hutchings ◽  
Cesare Hall
Keyword(s):  
Reynolds Number ◽  
Axial Compressor ◽  
Reynolds Numbers ◽  
Flow Coefficient ◽  
Total Size ◽  
Number Range ◽  
Stall Inception ◽  
Stable Operating ◽  
Compressor Performance ◽  
Stall Cells

Abstract Previous research into axial compressor stall has mainly focused on stall inception and methods to extend the stable operating range. This paper considers the performance of an axial compressor beyond stall and investigates how the characteristics of stall cells depend on Reynolds number. An experimental study has been conducted using a single-stage axial compressor capable of operating across the Reynolds number range of 10,000–100,000. Detailed unsteady measurements have been used to measure the behaviour across a range of install flow coefficients. These measurements have been used to extract the stall hysteresis and to determine the size, speed, number, and spanwise extent of the stall cells. The results show that for the stalled compressor, as Reynolds number increases, the size of the minimum stable stall cell decreases. This means that a larger change in throttle area is needed to reduce the stall cell down to a size where the compressor can recover from stall. At Re = 100,000, the stall hysteresis is six times greater than at Re = 20,000. At the design Reynolds number, the number of stall cells that form transitions from one, to two, and then to four stall cells as the flow coefficient is reduced. At lower Reynolds numbers, the two stall cell state becomes unstable; instead, a single stall cell transitions directly into five cells. In all cases, as the number of stall cells increases, so do the speed of the stall cells and the total size. Further reductions in the flow coefficient cause an increase in the total size of the stall cells and a decrease in the stall cell speed.

Effects of Reynolds Number on Performance Characteristics of a Centrifugal Compressor, With Special Reference to Configurations of Impellers

1975 ◽  
Vol 97 (3) ◽  
pp. 361-367 ◽  
Author(s):  
T. Mashimo ◽  
I. Watanabe ◽  
I. Ariga
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Special Reference ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Critical Reynolds Number ◽  
Performance Characteristics ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Flow Losses

The influences of Reynolds number on performance characteristics of centrifugal compressor were examined for various impeller configurations, that is, a double shrouded impeller with straight radial blades, a single shrouded impeller with straight radial blades, a single shrouded impeller with forward curved blades and a single shrouded impeller with backward curved blades. As a test equipment, a closed circuit of duct was employed, and the Reynolds number was varied by changing air pressure in a plenum chamber located upstream of the compressor. From the results, it was found that: (1) Among losses generated within a compressor stage, rates of losses independent of the Reynolds number became minimum at a certain flow coefficient. (2) As to the critical Reynolds number, the relation between relative surface roughness and critical Reynolds number for a stationary circular pipe is roughly applicable. (3) The secondary flow losses within impeller channels may be related to ζs = 51/Rewl0.5. In addition, the amount of each loss generated within a compressor stage was estimated.

IN-STALL COMPRESSOR PERFORMANCE AND THE EFFECTS OF REYNOLDS NUMBER

2022 ◽  
pp. 1-21
Author(s):  
Jack Hutchings ◽  
Cesare A. Hall
Keyword(s):  
Reynolds Number ◽  
Axial Compressor ◽  
Reynolds Numbers ◽  
Flow Coefficient ◽  
Total Size ◽  
Number Range ◽  
Stall Inception ◽  
Stable Operating ◽  
Compressor Performance ◽  
Stall Cells

Abstract Previous research into axial compressor stall has mainly focused on stall inception and methods to extend the stable operating range. This paper considers the performance of an axial compressor beyond stall and investigates how the characteristics of stall cells depend on Reynolds number. An experimental study has been conducted using a single-stage axial compressor capable of operating across the Reynolds number range of 10,000 – 100,000. Detailed unsteady measurements have been used to measure the behaviour across a range of in-stall flow coefficients. These measurements have been used to extract the stall hysteresis and to determine the size, speed, number, and spanwise extent of the stall cells. The results show that for the stalled compressor, as Reynolds number increases, the size of the minimum stable stall cell decreases. This means that a larger change in throttle area is needed to reduce the stall cell down to a size where the compressor can recover from stall. At the design Reynolds number, the number of stall cells that form transitions from one, to two, and then to four stall cells as the flow coefficient is reduced. At lower Reynolds numbers, the two-stall-cell state becomes unstable; instead, a single stall cell transitions directly into five stall cells. As the number of stall cells increases, so do the speed of the stall cells and the total size. Further reductions in the flow coefficient cause an increase in the total size and a decrease in the stall cell speed.

Numerical Study of the Reynolds Number Effect on the Centrifugal Compressor Performance and Losses

2016 ◽  
Author(s):  
Jonna Tiainen ◽  
Ahti Jaatinen-Värri ◽  
Aki Grönman ◽  
Jari Backman
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Numerical Results ◽  
Impeller Blade ◽  
Number Range ◽  
Compressor Performance ◽  
Low Reynolds ◽  
Correction Equations

The efficiency is reduced in very small centrifugal compressors due to low Reynolds numbers. In the past, the effect of the Reynolds number on centrifugal compressor performance has been studied experimentally, and empirical correction equations for the efficiency have been derived based on those results. There is a lack of numerical investigations into the effect of the Reynolds number on centrifugal compressor performance and losses. This paper aims to compare the numerical results to the efficiencies predicted by the correction equations found in the literature. The loss generation in the impeller blade passages is also studied in order to find out which loss production mechanism has the most potential to be reduced or eliminated. The effect of the Reynolds number on compressor performance is investigated in the chord Reynolds number range varying from 0.8 · 105 to 17 · 105 by simulating numerically the original compressors and downscaled ones. The numerical results are validated against experimental data and the results are compared with the efficiency correction equations used in the literature. The results indicate that the performance of the downscaled compressors follow quite precisely the most recently published correction equation. The results also show that the increased losses in low-Reynolds-number compressors are caused both by the relatively increased boundary layer thickness and by the shear stress resulting from the increased vorticity.

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