scholarly journals The Effect of Impeller Inlet Annular Turning Vanes on Multistage Centrifugal Compressor Performance

1996 ◽  
Author(s):  
Hélène Balligand ◽  
Xiubao Huang ◽  
Joost J. Brasz
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Performance Measurements ◽  
Channel Bend ◽  
Improvement Potential ◽  
Through Flow ◽  
Turning Radius ◽  
Return Channel ◽  
Radial Outflow ◽  
Multistage Centrifugal Compressor

The flow path of multistage centrifugal compressors is characterized by two 180-degree turns per stage: the inlet turning bend connecting the radial inflow return channel with the radial outflow impeller and the cross-over bend connecting the radial outflow diffuser with the return channel. Due to higher flow velocity and larger width to turning radius ratio, the turning losses are substantially higher in the inlet bend than in the return channel bend. Performance measurements were taken using different annular through-flow turning vane arrangements designed to reduce the inlet turning losses and increase the overall efficiency of the multistage centrifugal compressor. The experiments have shown consistent efficiency gains with corresponding capacity increases by adding multiple annular turning vanes in the inlet bend. The performance improvement potential of the vanes depends strongly on the positioning of these vanes in the flow passage. Based on these results, an empirical turning loss model was developed with the capability to predict the performance improvement achievable with correctly positioned single or multiple turning vanes in the impeller inlet bend area.

scholarly journals Performance Improvement of Return Channel in Multistage Centrifugal Compressor Using Multi-Objective Optimization

2012 ◽  
Author(s):  
Y. Nishida ◽  
H. Kobayashi ◽  
H. Nishida ◽  
K. Sugimura
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Coefficient ◽  
Swirl Flow ◽  
Optimized Design ◽  
Original Design ◽  
Flow Angle ◽  
Second Stage ◽  
Return Channel ◽  
Multistage Centrifugal Compressor ◽  
Stage Efficiency

The effect of the design parameters of a return channel on the performance of a multistage centrifugal compressor was numerically investigated, and the shape of the return channel was optimized using a multi-objective optimization method based on a genetic algorithm to improve the performance of the centrifugal compressor. The results of sensitivity analysis using Latin hypercube sampling suggested that the inlet-to-outlet area ratio of the return vane affected the pressure loss in the return channel, and that the inlet-to-outlet radius ratio of the return vane affected the outlet flow angle from the return vane. Moreover, this analysis suggested that the number of return vanes affected both the loss and the flow angle at the outlet. As a result of optimization, the number of return vanes was increased from 14 to 22 and the area ratio was decreased from 0.71 to 0.66. The radius ratio was also decreased from 2.1 to 2.0. Performance tests on a centrifugal compressor with two return channels (the original design and optimized design) were carried out using two-stage test apparatus. The measured flow distribution exhibited a swirl flow in the center region and a reversed swirl flow near the hub and shroud sides. The exit flow of the optimized design was more uniform than that of the original design. For the optimized design, the overall two-stage efficiency and pressure coefficient were increased by 0.7% and 1.5%, respectively. Moreover, the second-stage efficiency and pressure coefficient were respectively increased by 1.0% and 3.2%, It is considered that the increase in the second-stage efficiency was caused by the increased uniformity of the flow, and the rise in the pressure coefficient was caused by a decrease in the residual swirl flow. It was thus concluded from the numerical and experimental results that the optimized return channel improved the performance of the multistage centrifugal compressor.

scholarly journals Performance Improvement of a Return Channel in a Multistage Centrifugal Compressor Using Multiobjective Optimization

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yoshifumi Nishida ◽  
Hiromi Kobayashi ◽  
Hideo Nishida ◽  
Kazuyuki Sugimura
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Coefficient ◽  
Swirl Flow ◽  
Optimized Design ◽  
Original Design ◽  
Flow Angle ◽  
Second Stage ◽  
Return Channel ◽  
Multistage Centrifugal Compressor ◽  
Stage Efficiency

The effect of the design parameters of a return channel on the performance of a multistage centrifugal compressor was numerically investigated, and the shape of the return channel was optimized using a multiobjective optimization method based on a genetic algorithm to improve the performance of the centrifugal compressor. The results of sensitivity analysis using Latin hypercube sampling suggested that the inlet-to-outlet area ratio of the return vane affected the total pressure loss in the return channel, and that the inlet-to-outlet radius ratio of the return vane affected the outlet flow angle from the return vane. Moreover, this analysis suggested that the number of return vanes affected both the loss and the flow angle at the outlet. As a result of optimization, the number of return vane was increased from 14 to 22 and the area ratio was decreased from 0.71 to 0.66. The radius ratio was also decreased from 2.1 to 2.0. Performance tests on a centrifugal compressor with two return channels (the original design and optimized design) were carried out using two-stage test apparatus. The measured flow distribution exhibited a swirl flow in the center region and a reversed swirl flow near the hub and shroud sides. The exit flow of the optimized design was more uniform than that of the original design. For the optimized design, the overall two-stage efficiency and pressure coefficient were increased by 0.7% and 1.5%, respectively. Moreover, the second-stage efficiency and pressure coefficient were respectively increased by 1.0% and 3.2%. It is considered that the increase in the second-stage efficiency was caused by the increased uniformity of the flow, and the rise in the pressure coefficient was caused by a decrease in the residual swirl flow. It was thus concluded from the numerical and experimental results that the optimized return channel improved the performance of the multistage centrifugal compressor.

Effects of Return Channel With Splitter Vanes on Performance of Multistage Centrifugal Compressor

2015 ◽  
Author(s):  
Manabu Yagi ◽  
Takahiro Nishioka ◽  
Hiromi Kobayashi ◽  
Hideo Nishida ◽  
Satoru Yamamoto
Keyword(s):  
Centrifugal Compressor ◽  
High Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Flow Coefficient ◽  
Optimum Location ◽  
Trailing Edge ◽  
Overall Efficiency ◽  
Return Channel ◽  
Multistage Centrifugal Compressor

The effects of a return channel with splitter vanes on the performance of a multistage centrifugal compressor were investigated. As a preliminary study, the optimum location of the splitter vanes was numerically examined with the aim of achieving high overall efficiency. The results indicated that the optimum location was the 30% of the normalized pitchwise distance from the suction side of the main vane, with the leading-edge located at a radius ratio to the main vane trailing-edge of 1.77. To investigate the effects of the return channel with and without the optimum splitter vanes on the overall performance, performance tests were carried out using a one-and-half-stage test rig. Three pre-swirl vanes, whose vane angles from the tangential direction at the trailing-edge were 20, 30 and 40° were used to simulate three operating conditions with low, design and high flow coefficients, respectively. The design flow coefficient of the downstream impeller was 0.073 and the peripheral Mach number was 0.87. The test results showed that the return channel with the optimum splitter vanes achieved 11.8% higher overall efficiency at the high flow coefficient with respect to the case without the splitter vanes while maintaining the same efficiency at both low and design flow coefficients. The return channel with the optimum splitter vanes was concluded to be effective for improving the efficiency of a multistage centrifugal compressor.

Analysis of Rotordynamic and Thermodynamic Performance of a Multistage Centrifugal Compressor Operating in the Minimum Flow Region

2018 ◽  
Author(s):  
Marco Giachi ◽  
Giuseppe Vannini ◽  
Pier Luigi Di Pillo
Keyword(s):  
Thermodynamic Analysis ◽  
Centrifugal Compressor ◽  
Stable Condition ◽  
Flow Region ◽  
Negative Slope ◽  
Design Practice ◽  
Thermodynamic Performance ◽  
Free Machine ◽  
Multistage Centrifugal Compressor ◽  
Day By Day

In this paper both rotordynamic and thermodynamic analysis of a multistage centrifugal compressor running with one or more stages in post-stall condition are presented. The purpose of this study is to demonstrate the machine can operate stable and safe in such condition (i.e. stable condition means the head vs. flow operating curve shall have negative slope and safe means a vibration free machine). This allows to extend the operating range at lower flow with respect to the current day-by-day design practice. Experimental results from ASME PTC10 Class 2 test carried out on a seven-stage compressor are shown to validate the analysis.

Multistage Centrifugal Compressor Surge Analysis: Part II—Numerical Simulation and Dynamic Control Parameters Evaluation

1999 ◽  
Vol 121 (2) ◽  
pp. 312-320 ◽  
Author(s):  
G. L. Arnulfi ◽  
P. Giannattasio ◽  
C. Giusto ◽  
A. F. Massardo ◽  
D. Micheli ◽  
...  
Keyword(s):  
Active Control ◽  
Centrifugal Compressor ◽  
Dynamic Control ◽  
Point Of View ◽  
Lumped Parameter Model ◽  
Theoretical Point ◽  
Control Parameters ◽  
Compression System ◽  
Compressor Surge ◽  
Multistage Centrifugal Compressor

This paper describes, from a theoretical point of view, the behavior of compression systems during surge and the effect of passive and active control devices on the instability limit of the system. A lumped parameter model is used to simulate the compression system described in Part I of this work (Arnulfi et al., 1999), based on an industrial multistage centrifugal compressor. A comparison with experimental results shows that the model is accurate enough to describe quantitatively all the features of the phenomenon. A movable wall control system is studied in order to suppress surge in the compressor. Passive and active control schemes are analyzed; they both address directly the dynamic behavior of the compression system to displace the surge line to lower flow rates. The influence of system, geometry and compressor speed is investigated: the optimum values of the control parameters and the corresponding increase in the extent of the stable operating range are presented in the paper.

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