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.

scholarly journals Effects of Reynolds Number on Performance Characteristics of a Centrifugal Compressor

1971 ◽  
Author(s):  
Toshio Mashimo ◽  
Hiroshi Suefusa ◽  
Ichiro Ariga ◽  
Ichiro Watanabe
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Critical Reynolds Number ◽  
Performance Characteristics ◽  
The Other ◽  
Compressor Stage ◽  
Other Hand ◽  
Compressor Performance ◽  
Experimental Equation

The influences of the Reynolds number on centrifugal compressor performance have not so much been investigated. Especially, the experimental equation representing the rates of losses for the critical Reynolds number has been seemingly not established. Namely, the coefficients in the equation differ with each investigator. In the present study, an experiment was conducted by means of an experimental centrifugal compressor. From the results, it was found that the critical Reynolds number Recmeancr was reasonable for the compressor stage as well as for the impeller, and for the former it amounted to about 0.9∼1.3 × 105, while for the latter it amounted to about 0.9∼1.2 × 105. On the other hand, the critical Reynolds number Rec2cr was also found appropriate for the diffuser and it amounted to about 0.9∼1.5 × 105. In addition, the coefficients in the experimental equation which introduced the rate of losses were estimated.

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).

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.

scholarly journals Influence of blade geometry on secondary flow development in a transonic centrifugal compressor

2018 ◽  
Vol 2 ◽  
pp. I1RSJ3 ◽  
Author(s):  
Moritz Mosdzien ◽  
Martin Enneking ◽  
Alexander Hehn ◽  
Daniel Grates ◽  
Peter Jeschke
Keyword(s):  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Large Scale ◽  
Optimization Methods ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Flow Development ◽  
Transonic Centrifugal Compressor ◽  
Increasing Demand

Due to the increasing demand for higher efficiencies of centrifugal compressors, numerical optimization methods are becoming more and more relevant in the design process. To identify the beneficial features of a numerical optimized compressor design, this paper analyses the influence of arbitrary blade surfaces on the loss generation in a transonic centrifugal compressor. The paper therefore focuses on an analysis of the secondary flow development within the impeller blade passages. To do this, steady simulations were performed on both a baseline and an optimized blade design. Two distinct design features of the optimized compressor stage were identified, which lead to a more homogenous impeller exit flow and thus to an increase in total-to-static efficiency of 1.76% points: the positive lean in the near-tip region and the positive blade curvature in the rear part of the optimized impeller. Furthermore, through extensive experimental investigations conducted on a large scale test rig it has been possible to prove the particular impeller outflow characteristics of the baseline compressor stage.

1D and 3D-Design Strategies for Pressure Slope Optimization of High-Flow Transonic Centrifugal Compressor Impellers

2018 ◽  
Author(s):  
A. Hildebrandt ◽  
T. Ceyrowsky
Keyword(s):  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Angle Distribution ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Design Point ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor

The present paper deals with the numerical and theoretical investigations of the effect of geometrical dimensions and 1D-design parameters on the impeller pressure slope of a transonic centrifugal compressor stage for industrial process application. A database being generated during the multi-objective and multi-point design process of a high flow coefficient impeller, comprising 545 CFD (Computational Fluid Dynamics) designs is investigated in off-design and design conditions by means of RANS (Reynolds Averaged Navier Stokes) simulation of an impeller with vaneless diffuser. For high flow coefficients of 0.16 < phi < 0.18, the CFD-setup has been validated against measurement data regarding stage and impeller performance taken from MAN test rig experimental data for a centrifugal compressor stage of similar flow coefficient. The paper aims at answering the question how classical design parameter, such as the impeller blade angle distribution, impeller suction diameter and camber line length affect the local and total relative diffusion and pressure slope towards impeller stall operation. A second order analysis of the CFD database is performed by cross-correlating the CFD data with results from impeller two-zone 1D modelling and a rapid loading calculation process by Stanitz and Prian. The statistical covariance of first order 1D-analysis parameters such as the mixing loss of the impeller secondary flow, the slip factor, impeller flow incidence is analyzed, thereby showing strong correlation with the design and off-design point efficiency and pressure slope. Finally, guide lines are derived in order to achieve either optimized design point efficiency or maximum negative pressure slope characteristics towards impeller stall operation.

Laser Transit Anemometry Investigation of a High Speed Centrifugal Compressor

1989 ◽  
Author(s):  
David Japikse ◽  
David M. Karon
Keyword(s):  
Experimental Investigation ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Turbulence Intensity ◽  
High Speed ◽  
Flow Regimes ◽  
Compressor Stage ◽  
Blade Passage ◽  
Centrifugal Compressor Stage

A detailed experimental investigation of a small centrifugal compressor stage has been completed using laser transit anemometry. Measurements at the inlet and discharge of an impeller have been made while recording data relative to a blade passage. Classical primary and secondary flow regimes within the rotor have been shown plus several compact “cell-like” regions. Various components of velocity and turbulence intensity are presented. This study has demonstrated the capability of using the laser transit anemometer for investigating the kinematics of small, high speed turbomachinery components.

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