Effect of Impeller Blade Loading on Compressor Stage Performance in a High Specific Speed Range

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Takanori Shibata ◽  
Manabu Yagi ◽  
Hideo Nishida ◽  
Hiromi Kobayashi ◽  
Masanori Tanaka
Keyword(s):  
Relative Velocity ◽  
Compressor Stage ◽  
Test Results ◽  
Blade Loading ◽  
Degree Of Reaction ◽  
Surge Margin ◽  
Speed Range ◽  
Specific Speed ◽  
Velocity Diffusion ◽  
Stage Efficiency

The authors previously found that compressor stage efficiency in a high specific speed range was significantly improved by employing an increased relative velocity diffusion ratio coupled with a high backsweep angle (Shibata et al., “Performance Improvement of a Centrifugal Compressor Stage by Increasing Degree of Reaction Optimizing Blade Loading of a 3D-Impeller,” ASME Paper No. GT2009-59588). In spite of such a high relative velocity diffusion ratio, the same surge margin as with a conventional design was able to be achieved by using a special front loading distribution with a lightly loaded inducer. In the present study, the blade loading distribution was further optimized in order to achieve a larger surge margin than previously. Four types of fully shrouded impellers were designed, manufactured, and tested to evaluate the effects of blade loading, backsweep angle, and relative velocity diffusion ratio on compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that the developed impeller achieved 3.8% higher stage efficiency and 11% larger surge margin than the conventional design without reducing the pressure coefficient and choke margin. It was concluded that aft loading coupled with a high degree of reaction was a very effective way to improve surge margin as well as stage efficiency. Stator matching was also investigated by changing the design incidence angle, which was shown to have a little influence on surge margin in the present test results.

Effect of Impeller Blade Loading on Compressor Stage Performance in a High Specific Speed Range

2010 ◽  
Author(s):  
Takanori Shibata ◽  
Manabu Yagi ◽  
Hideo Nishida ◽  
Hiromi Kobayashi ◽  
Masanori Tanaka
Keyword(s):  
Relative Velocity ◽  
Compressor Stage ◽  
Test Results ◽  
Blade Loading ◽  
Conventional Design ◽  
Surge Margin ◽  
Speed Range ◽  
Specific Speed ◽  
Velocity Diffusion ◽  
Stage Efficiency

The authors previously found that compressor stage efficiency in a high specific speed range was significantly improved by employing an increased relative velocity diffusion ratio coupled with a high backsweep angle. In spite of such a high relative velocity diffusion ratio, the same surge margin as with a conventional design could be achieved by using a special front loading distribution with a lightly loaded inducer. In the present study, the blade loading distribution was further optimized in order to achieve a larger surge margin than previously. Four types of fully shrouded impellers were designed, manufactured and tested to evaluate the effects of blade loading, backsweep angle and relative velocity diffusion ratio on compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that the developed impeller achieved 3.8% higher stage efficiency and 11% larger surge margin than the conventional design without reducing the pressure coefficient and choke margin. It was concluded that aft loading coupled with a high degree of reaction was a very effective way to improve surge margin as well as stage efficiency. Stator matching was also investigated by changing the design incidence angle which was shown to have little influence on surge margin in the present test results.

Performance Improvement of a Centrifugal Compressor Stage by Increasing Degree of Reaction and Optimizing Blade Loading of a 3D Impeller

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Takanori Shibata ◽  
Manabu Yagi ◽  
Hideo Nishida ◽  
Hiromi Kobayashi ◽  
Masanori Tanaka
Keyword(s):  
Performance Improvement ◽  
Relative Velocity ◽  
High Efficiency ◽  
Pressure Coefficient ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Blade Loading ◽  
Surge Margin ◽  
Velocity Diffusion ◽  
Stage Efficiency

Performance improvement of 3D impellers in a high specific speed range was investigated using computational fluid dynamics analyses and experimental tests. In order to reduce the loss production within the stator passages, the backsweep angle of the impellers was increased. At the same time, the inlet-to-exit relative velocity diffusion ratio was also increased by increasing the impeller exit width to prevent the reduction in the pressure ratio. Moreover, the blade loading distribution at the impeller shroud side was optimized to suppress the surge margin reduction caused by the increased relative velocity diffusion ratio. Five types of unshrouded impellers were designed, manufactured, and tested to evaluate the effects of blade loading, backsweep angle, and relative velocity diffusion ratio on the compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that the compressor stage efficiency was increased by 5% compared with the base design without reducing the pressure coefficient and surge margin. It was concluded that an increased relative velocity diffusion ratio coupled with large backsweep angle was a very effective way to improve the compressor stage efficiency. An appropriate blade loading distribution was also important in order to achieve a wide operating range as well as high efficiency.

Performance Improvement of a Centrifugal Compressor Stage by Increasing Degree of Reaction and Optimizing Blade Loading of a 3D-Impeller

2009 ◽  
Author(s):  
Takanori Shibata ◽  
Manabu Yagi ◽  
Hideo Nishida ◽  
Hiromi Kobayashi ◽  
Masanori Tanaka
Keyword(s):  
Performance Improvement ◽  
Relative Velocity ◽  
High Efficiency ◽  
Pressure Coefficient ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Blade Loading ◽  
Surge Margin ◽  
Velocity Diffusion ◽  
Stage Efficiency

Performance improvement of 3D impellers in a high specific speed range was investigated using computational fluid dynamics (CFD) analyses and experimental tests. In order to reduce the loss production within the stator passages, the backsweep angle of the impellers was increased. At the same time, the inlet-to-exit relative velocity diffusion ratio was also increased by increasing impeller exit width to prevent the reduction in pressure ratio. Moreover, the blade loading distribution at the impeller shroud side was optimized to suppress the surge margin reduction caused by the increased relative velocity diffusion ratio. Five types of unshrouded impellers were designed, manufactured and tested to evaluate the effects of blade loading, backsweep angle and relative velocity diffusion ratio on compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that compressor stage efficiency was increased by 5% compared to the base design without reducing the pressure coefficient and surge margin. It was concluded that an increased relative velocity diffusion ratio coupled with large backsweep angle was a very effective way to improve compressor stage efficiency. An appropriate blade loading distribution was also important in order to achieve a wide operating range as well as high efficiency.

Effect of the Exit System on the Performance of a Low Specific Speed Industrial Centrifugal Compressor Stage

2003 ◽  
Author(s):  
Jean-Luc Di Liberti
Keyword(s):  
Centrifugal Compressor ◽  
High Frequency ◽  
Rotating Stall ◽  
Cfd Analysis ◽  
Compressor Stage ◽  
Test Results ◽  
Centrifugal Compressor Stage ◽  
Surge Margin ◽  
Low Specific Speed ◽  
Specific Speed

A low specific speed stage was tested with two different size volutes and a return vane system. The stage was instrumented with pressure probes at various locations, including the inlet and discharge flanges, diffuser inlet, diffuser exit, and return vane inlet. Cobra probes were positioned at the diffuser inlet and the return vane inlet for the return vane configuration to measure the flow angles. High frequency transducers were installed in the diffuser. This paper presents the test results showing the effect of two different volute sizes and of the return vane system on surge margin, rotating stall onset, and overall rotor and stage performance. Rotating stall criteria are reviewed, since this stage was previously tested with a different diffuser pinch. The performance is compared with some CFD analysis.

A Diffusion Factor Correlation for Centrifugal Impeller Stalling

1978 ◽  
Vol 100 (4) ◽  
pp. 592-601 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Centrifugal Compressor ◽  
High Loading ◽  
Centrifugal Impeller ◽  
Preliminary Design ◽  
Test Results ◽  
Diffusion Factor ◽  
Speed Range ◽  
Parallel Wall ◽  
Specific Speed ◽  
Vaneless Diffusers

Test results pertaining to the stalling characteristics of centrifugal compressor impellers with parallel wall vaneless diffusers are presented and studied to correlate the coincidence of stall with a limiting impeller diffusion capability. It is suggested that a modified diffusion factor, to include the effects of meridional curvature, provides improved stall correlation for a wide specific speed range of backswept impeller types. The possibility of applying this diffusion factor to high loading radially bladed impellers is discussed as dependent upon blockage and windage plus recirculation effects. Use of the diffusion factor limit in the preliminary design of most common turbomachinery types, incompressible and compressible, to assess impeller (or rotor) stall is conceivable.

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

Redesign of a Compressor Stage for a High-Performance Electric Supercharger in a Heavily Downsized Engine

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Peng Wang ◽  
Mehrdad Zangeneh ◽  
Bryn Richards ◽  
Kevin Gray ◽  
James Tran ◽  
...  
Keyword(s):  
Design Method ◽  
Pressure Ratio ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Surge Margin ◽  
Stable Operating ◽  
Inverse Design Method ◽  
Ported Shroud

Engine downsizing is a modern solution for the reduction of CO2 emissions from internal combustion engines. This technology has been gaining increasing attention from industry. In order to enable a downsized engine to operate properly at low speed conditions, it is essential to have a compressor stage with very good surge margin. The ported shroud, also known as the casing treatment, is a conventional way used in turbochargers to widen the working range. However, the ported shroud works effectively only at pressure ratios higher than 3:1. At lower pressure ratio, its advantages for surge margin enhancements are very limited. The variable inlet guide vanes are also a solution to this problem. By adjusting the setting angles of variable inlet guide vanes, it is possible to shift the compressor map toward the smaller flow rates. However, this would also undermine the stage efficiency, require extra space for installing the inlet guide vanes, and add costs. The best solution is therefore to improve the design of impeller blade itself to attain high aerodynamic performances and wide operating ranges. This paper reports a recent study of using inverse design method for the redesign of a centrifugal compressor stage used in an electric supercharger, including the impeller blade and volute. The main requirements were to substantially increase the stable operating range of the compressor in order to meet the demands of the downsized engine. The three-dimensional (3D) inverse design method was used to optimize the impeller geometry and achieve higher efficiency and stable operating range. The predicted performance map shows great advantages when compared with the existing design. To validate the computational fluid dynamics (CFD) results, this new compressor stage has also been prototyped and tested. It will be shown that the CFD predictions have very good agreement with experiments and the redesigned compressor stage has improved the pressure ratio, aerodynamic efficiency, choke, and surge margins considerably.

scholarly journals MS7001F Prototype Test Results

1989 ◽  
Author(s):  
D. E. Brandt
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Load Test ◽  
Test Results ◽  
Critical Temperatures ◽  
Prototype Test ◽  
Surge Margin ◽  
Pertinent Data ◽  
Post Test ◽  
Heavy Duty Gas Turbine

The MS7001F heavy–duty gas turbine has been designed utilizing advanced analytical methods and a substantial array of component tests. The integrity of the system required that the prototype unit, with its accessories, be rigorously tested under load. The factory load test was completed on May 18, 1988 after 387 hours and 134 start/stop cycles. The MS7001F prototype gas turbine was instrumented with more than 3000 pieces of instrumentation in order to record all critical temperatures, pressures, flows, strains, displacements, and other pertinent data. The load device was a modified MS7001E compressor, which also supplied the means by which the MS7001F prototype compressor’s pressure ratio was increased to provide for surge margin determination. Inlet throttling of the MS7001F compressor allowed for full firing temperature operation, at reduced load. The results of this factory prototype load test are reported in the paper as are observations made during post test teardown.

Trailing Edge Filings and a Modified Stodola’s Slip Factor for Centrifugal Impeller

2015 ◽  
Author(s):  
Guang Xi ◽  
Huijing Zhao ◽  
Zhiheng Wang
Keyword(s):  
Numerical Simulations ◽  
Good Accuracy ◽  
Centrifugal Impeller ◽  
Pressure Side ◽  
Compressor Stage ◽  
Trailing Edge ◽  
Obvious Effect ◽  
Quantitative Calculation ◽  
Slip Factor ◽  
Stage Efficiency

The paper investigates the effect of trailing edge filing in the impeller on the performances of impeller and compressor stage. The 3D viscous numerical simulations are carried out under different positions, thicknesses and lengths of filing. The results show that, the filing on the trailing edge has an obvious effect on the pressure ratios of impeller and compressor stage. The trailing edge filing has little effect on the impeller efficiency while the filing on the pressure side is favorable to improving the stage efficiency. Then, through correcting the blade angles at the suction and pressure sides, considering the viscosity and 3D characteristics of the flow, a modified slip factor formula is proposed for the centrifugal impeller with a trailing edge filing. The validation to the proposed formula shows that the proposed formula can be used to predict the slip factors of different filing cases with a good accuracy. It can provide a theoretical guidance for the quantitative calculation when using the filing technology to improve the performance of centrifugal impeller as well as the stage.

Development of a High Specific Speed Centrifugal Compressor

1996 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Centrifugal Compressor ◽  
Test Performance ◽  
Pressure Ratio ◽  
High Volume ◽  
Limited Information ◽  
Component Test ◽  
Booster Compressor ◽  
Specific Speed ◽  
Stage Efficiency ◽  
Very High

This paper describes the development of a subscale single stage centrifugal compressor with a dimensionless specific speed (Ns) of 1.8, originally designed for full size appllcatioa as a high volume flow, low pressure ratio, gas booster compressor. The specific stage is noteworthy in that it provides a benchmark representing the performance potential of very high specific speed compressors of which limited information is found in open literature. Stage & component test performance characteristics are presented together with traverse results at the impeller exit. Traverse test results were compared with recent CFD computational predictions, for a exploratory analytical callbration of a very high specific speed impeller geometry. The tested subscale (0.583) compressor essentially satisfied design performance expectations with an overall stage efficiency of 74% incinding, excessive exit casing losses. It was estimated that stage efficiency could be increased to 81% with exit casing losses halved.

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