scholarly journals Discussion: “Effects of Reynolds Number on Performance Characteristics of a Centrifugal Compressor, With Special Reference to Configurations of Impellers” (Mashimo, T., Watanabe, I., and Ariga, I., 1975, ASME J. Eng. Power, 97, pp. 361–367)

1975 ◽  
Vol 97 (3) ◽  
pp. 367-367
Author(s):  
A. Whitfield ◽  
F. J. Wallace
Keyword(s):  
Reynolds Number ◽  
Special Reference ◽  
Centrifugal Compressor ◽  
Performance Characteristics

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.

The Effect of Inlet Distortion on the Performance Characteristics of a Centrifugal Compressor

1983 ◽  
Vol 105 (2) ◽  
pp. 223-230 ◽  
Author(s):  
I. Ariga ◽  
N. Kasai ◽  
S. Masuda ◽  
Y. Watanabe ◽  
I. Watanabe
Keyword(s):  
Centrifugal Compressor ◽  
Total Pressure ◽  
Performance Characteristics ◽  
Performance Tests ◽  
Velocity Measurements ◽  
Test Rig ◽  
Low Speed ◽  
Inlet Distortion ◽  
Surge Margin ◽  
The Given

The present paper concerns itself with the effects of total pressure (and thus velocity) distortion on performance characteristics and surge margin of centrifugal compressors. Both radial and circumferential distortions were investigated. The performance tests as well as the velocity measurements within the impeller passages were carried out with a low-speed compressor test rig with the inlet honeycomb as the distortion generators and compared with the case of “no distortion” as a datum. The results indicated that the inlet distortion exerted unfavorable influences on the efficiency and the surge margin of the given compressor, though the influence of the radial distortion was much stronger than that of the circumferential one. Various distortion indices were further examined in order to correlate the performance to the inlet distortion.

scholarly journals Computational Analysis of the Performance Characteristics of a Supercritical CO2 Centrifugal Compressor

Computation ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 54 ◽  
Author(s):  
Senthil Raman ◽  
Heuy Kim
Keyword(s):  
Centrifugal Compressor ◽  
Stokes Equations ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Performance Characteristics ◽  
Supercritical Regime ◽  
Vaned Diffuser

A centrifugal compressor working with supercritical CO 2 (S-CO 2 ) has several advantages over other supercritical and conventional compressors. S-CO 2 is as dense as the liquid CO 2 and becomes difficult to compress. Thus, during the operation, the S-CO 2 centrifugal compressor requires lesser compression work than the gaseous CO 2 . The performance of S-CO 2 compressors is highly varying with tip clearance and vanes in the diffuser. To improve the performance of the S-CO 2 centrifugal compressor, knowledge about the influence of individual components on the performance characteristics is necessary. This present study considers an S-CO 2 compressor designed with traditional engineering design tools based on ideal gas behaviour and tested by SANDIA national laboratory. Three-dimensional, steady, viscous flow through the S-CO 2 compressor was analysed with computational fluid dynamics solver based on the finite volume method. Navier-Stokes equations are solved with K- ω (SST) turbulence model at operating conditions in the supercritical regime. Performance of the impeller, the main component of the centrifugal compressor is compared with the impeller with vaneless diffuser and vaned diffuser configurations. The flow characteristics of the shrouded impeller are also studied to analyse the tip-leakage effect.

The Distribution and Stability of Flow in a Rotating Channel

1968 ◽  
Vol 90 (3) ◽  
pp. 229-235 ◽  
Author(s):  
H. S. Fowler
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Centrifugal Compressor ◽  
Channel Wall ◽  
Flow Distribution ◽  
Stability Change ◽  
The Stability ◽  
Downstream Flow ◽  
Adjacent Channels ◽  
Rotating Channel

The importance of flow distribution and stability leaving the impeller of a centrifugal compressor is discussed. Experiments on the flow in converging, parallel, and diffusing channels, representative of sections of impeller channels, are reported and discussed. The convergent or divergent character of the channel appears to have less influence on the flow pattern than on the stability. Change of Reynolds number appears to change the degree of nonuniformity of distribution in the channel, but change of rotation number appears to affect the distribution of the nonuniformity more. It appears that the influence of adjacent channels, and of the downstream flow-field in general, has a large effect on the flow within the rotating channel, particularly as regards detachment from the suction channel wall. “No man is an island unto himself,” and no element in an aerodynamic system can be divorced from its upstream or downstream neighbors.

Performance Characteristics of Two- and Three-Dimensional Impellers in Centrifugal Compressors

1988 ◽  
Vol 110 (1) ◽  
pp. 110-114 ◽  
Author(s):  
H. Harada
Keyword(s):  
Centrifugal Compressor ◽  
Closed Loop ◽  
Three Dimensional ◽  
Test Stand ◽  
Performance Characteristics ◽  
Working Fluid ◽  
Angle Distribution ◽  
Blade Angle ◽  
Operating Range ◽  
Overall Performance

The overall performance of two- and three-dimensional impellers of a centrifugal compressor were tested and compared. A closed-loop test stand with Freon gas as the working fluid was employed for the experiments. The inlet and outlet velocity distributions of all impellers were measured using three-hole cobra probes. As a result, it has been revealed that three-dimensional impeller in terms of efficiency, head coefficient, and operating range. Further, it has also been clarified that the impeller slip factor is affected by blade angle distribution.

Performance characteristics of a chilled water spirally coiled finned tube in cross flow for air conditioning applications

2012 ◽  
Vol 227 (2) ◽  
pp. 320-331 ◽  
Author(s):  
Abdalla Gomaa ◽  
Wael IA Aly ◽  
Ashraf Mimi Elsaid ◽  
Eldesuki I Eid
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Friction Factor ◽  
Flow Direction ◽  
Cross Flow ◽  
Finned Tube ◽  
Performance Characteristics ◽  
Curvature Ratio ◽  
Coiled Tube ◽  
Chilled Water

In the present study, the thermo-fluid characteristics of a spirally coiled finned tube in cross flow were experimentally investigated. This investigation covered different design parameters such as curvature ratio, air velocity, flow direction, fin pitch and flow rate of chilled water on performance characteristics of the spirally coiled finned tube. The purpose was to evaluate this kind of the spirally finned-tube cooling coils with particular reference to bare coiled tube. Six test specimens were designed and manufactured with curvature ratios of 0.027, 0.03, 0.04, tube pitches of 18, 20, 30 mm and fin pitches of (33, 22, 11 mm). Experiments were carried out in a pilot wind tunnel with air Reynolds number ranging from 35,500 to 245,000. Two types of chilled water flow directions entering the spiral coil were tested at Reynolds number ranging from 5700 to 25,300, the first was inward flow direction and the other was to outward flow direction. The results revealed that the inward flow direction has significant enhancement effect on the Nusselt number compared with outward flow direction by 37.0% for tube pitch of 18 mm and curvature ratio of 0.027. The decrease of fin pitch enhances the Nusselt number by 21.92% on expense of friction factor by 10.9%. In the case of spirally coiled bare tube, the decreasing of the curvature ratio increases air side Nusselt number by 33.69% on expense of friction factor by 18.36%. General correlations of Nusselt number and air friction factor for bare and finned spirally coiled tube were correlated based on reported experimental data.

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