Performance Analysis and Improvement of a Centrifugal Compressor Based on Partial Similarity Principle

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Hong Xie ◽  
Bo Yang ◽  
Shuyi Zhang ◽  
Moru Song
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Tip Clearance ◽  
Scaled Model ◽  
Partial Similarity ◽  
Similarity Principle ◽  
Scaling Process ◽  
Flow Similarity

Abstract In this paper, with the help of partial similarity principle, aerodynamic performance of a centrifugal compressor in a turbocharger unit is analyzed and improved based on a low-speed large-scaled model. In order to achieve flow similarity between the scaled compressor and the prototype, tip clearance and diffuser outlet diameter have been modified further. It is observed from the numerical results that the relative error between the scaled compressor and the prototype is less than 0.8%. It means that the flow field of the scaled compressor is similar to the prototype though the Reynolds number is neglected during the scaling process. Furthermore, the large-scaled impeller has been improved by analyzing the numerical results, and then, the improved impeller is scaled down back to the smaller one by using the partial similarity principle, which geometric dimensions have the same level as those of the prototype but performance is improved obviously. Meanwhile, the experiment results are used to validate the method.

Effects of Reynolds Number and Tip Clearances on the Performance of a Centrifugal Compressor at Micro Scale

2006 ◽  
Author(s):  
Kousuke Isomura ◽  
Susumu Teramoto ◽  
Shin-Ichi Togo ◽  
Kousuke Hikichi ◽  
Yuki Endo ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Scale Up ◽  
Tip Clearance ◽  
Test Results ◽  
Turbine Engine ◽  
Micro Scale ◽  
Heat Leakage ◽  
Calculation Results

The performance of a centrifugal compressor at micro-scale has been assessed by a combination of experiments and numerical calculations. A micro-compressor of 10mm diameter has been fabricated and tested at the condition of 75μm tip clearance. The test results showed higher adiabatic efficiencies than the target value for the compressor to realize a 100W class gas turbine generator. However, this is due to the heat leakage, and a heat leakage model is proposed to be added in the numerical simulations. After matching the calculation results to the experimental results by modeling the heat loss through the wall, calculations of various Reynolds number and tip clearances have been conducted. The study shows that the rate of efficiency reduction due to the increase of the tip clearance is within the range of the data that Pampreen [5] used to construct his model, and the micro-compressor can achieve the target efficiency either by reducing the tip clearance to 15μm, which is practically too small to be achieved. The alternatives methods to achieve the target efficiency are to increase the blade height for about three times, or scale up the compressor. These methods require the increase of the power output of the target gas turbine engine. The study shows that the target efficiency can be better achieved by scaling up the impeller to 15mm diameter to allow increasing the tip clearance to 50μm.

Effect of the tip clearance variation on the performance of a centrifugal compressor with considering impeller deformation

2011 ◽  
Vol 225 (8) ◽  
pp. 1143-1155 ◽  
Author(s):  
H-L Wang ◽  
G Xi ◽  
J-Y Li ◽  
M-J Yuan
Keyword(s):  
Centrifugal Compressor ◽  
Great Influence ◽  
Pressure Rise ◽  
Aerodynamic Performance ◽  
Structure Design ◽  
Tip Clearance ◽  
Working Environment ◽  
Field Analysis ◽  
The Real ◽  
Aerodynamic Pressure

The effects of impeller tip clearance variation on centrifugal compressor performance have been investigated experimentally and numerically in a centrifugal compressor. In order to accurately calculate the real tip clearance, the influence of impeller geometry deformation caused by the thermal load (temperature variation) and mechanical loads (aerodynamic pressure and centrifugal force) under working condition on the compressor aerodynamic performance is taken into account by fluid/solid interaction method during the computational fluid dynamics flow field analysis process. In this article, tip clearance flow under the real working environment is investigated with three different tip clearance cases. The impeller deformation combined with the adjustment of tip clearance causes some influence on the aerodynamic performance and on the structure reliability of the compressor system. For the aerodynamic design, an increase in the impeller tip clearance decreases the overall pressure rise and isentropic efficiency of the compressor, mainly due to the tip clearance loss in the impeller. Regarding structure design, the uniform relative tip clearance from the inlet to the outlet CR = 7.3 per cent is changed to non-uniform distribution from 6.4 per cent to 4.15 per cent. The largest deformation location occurs at the blade inducer and trailing-edge tip. The relative clearance near the outlet of the blade is reduced about 3.15 per cent which will cause great influence on the impeller working reliability.

Effects of Fluid Leakage on Performance of a Centrifugal Compressor

1979 ◽  
Vol 101 (3) ◽  
pp. 337-342 ◽  
Author(s):  
T. Mashimo ◽  
I. Watanabe ◽  
I. Ariga
Keyword(s):  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Friction Loss ◽  
Wall Friction ◽  
Fluid Loss ◽  
Leakage Loss ◽  
Compressor Performance

Fluid loss caused by leaks through the impeller tip clearance was investigated for a centrifugal compressor. Operating conditions, Reynolds number, and clearance were varied independently during the experiment. It was found that the average compressor performance would be reduced by about 4 percent when the relative clearance was increased from 0.0125 to 0.125 and the resulting leakage loss was dependent on the Reynolds number, the tendency of which was just opposite in case of wall friction loss, as was well-known. Moreover, a determination of the leakage loss coefficient was made as a function of the relative clearance, relative leak level and the Reynolds number as the result of this experiment.

Effects of number of inlet guide vanes on the aerodynamic performance of a centrifugal compressor

2021 ◽  
pp. 095765092110268
Author(s):  
M Anbarsooz ◽  
M Amiri ◽  
A Erfanian ◽  
E Benini
Keyword(s):  
Centrifugal Compressor ◽  
Inclination Angle ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Maximum Efficiency ◽  
Optimum Number ◽  
Performance Curve ◽  
Guide Vanes ◽  
Inlet Guide Vanes

Variable inlet guide vanes (VIGVs) are widely used for flow throttling and also extending the operating range of centrifugal compressors. Although there are several studies on the effects of adding IGVs on the performance curve of the compressors, none of them have focused on the number of vanes. In the current study, high-fidelity three-dimensional numerical simulations are carried out to analyze the effects of adding VIGVs with different number of vanes on the aerodynamic performance of a single-stage centrifugal compressor. The selected compressor prototype is a high flowrate single-stage compressor equipped with a vaned diffuser, designed and fabricated by Siemens. Computational fluid dynamic simulations are performed for three different number of guide vanes at three IGV inclination angles of 0, −30 and +45 degrees. The numerical results are validated by comparing the pressure-rise curves with the available experimental data of the compressor data sheet, where a good agreement was achieved. Results show that at the fully-open condition, the number of vanes does not have considerable effect on the performance curve of the compressor. However, as the IGV inclination angle increases, the number of inlet vanes plays a considerable role in the compressor efficiency. For example, at IGV inclination angle of +45 degree, increasing the number of vanes from 7 to 11 can increase the compressor maximum efficiency up to 5 points. Numerical results showed that increasing the number of inlet guide vanes imposes a higher pressure drop in the inlet passage of the compressor while generating a more uniform velocity distribution at the suction surface of the impeller. Due to the existence of several counteracting effects, an optimum number of inlet guide vanes can be found.

scholarly journals Research on the Application of Partial Similarity for a 1-1/2 Axial Compressor

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1121
Author(s):  
Hong Xie ◽  
Moru Song ◽  
Bo Yang
Keyword(s):  
Low Cost ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Optimization Method ◽  
Casing Treatment ◽  
Partial Similarity ◽  
Similarity Principle ◽  
Performance Curves ◽  
Flow Similarity ◽  
The Impact

In this paper, a method based on the partial similarity principle is presented to improve the aerodynamic design with low cost and high accuracy for a 1-1/2 axial compressor. By means of this method, during the process of a similar design, the machine Mach number and flowrate coefficient are maintained. The flow similarity between the prototype and its large-scaled alternative was observed, according to a detailed analysis of flow fields of rotor and stator. As well, the relative discrepancies of isentropic efficiency and pressure ratio between two models are 1.25% and 0.4% at design point, respectively. Besides, their performance curves agreed very well in the whole operating range. Moreover, it was also found that the flow similarity between the two models can be maintained under unsteady working conditions. Thereafter, in order to investigate the impact of stability optimization method on the similarity principle, casing treatment with single circumferential groove was applied to these two models. The flow similarity was still maintained and the flowrate near the stall was reduced about 1.1% with negligible deterioration of the overall performance.

Effects of Reynolds Number and Heat Transfer on Scaling of a Centrifugal Compressor Impeller

2010 ◽  
Author(s):  
Yan Ma ◽  
Guang Xi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Small Scale ◽  
Adiabatic Wall ◽  
Flow Solver ◽  
Similarity Principle ◽  
Wall Condition ◽  
Compressor Impeller ◽  
Exponential Relation

In this paper, the influence of Reynolds number and heat transfer on scaling of a small scale centrifugal compressor impeller was investigated. The flow solver EURANUS, integrated in the FINE/Turbo interface, was used in the numerical simulation. With the application of the similarity principle, the baseline impeller was scaled with a factor of 1/5 and 5 respectively. Using the baseline impeller as reference, an exponential relation between efficiency loss and Reynolds number was used in this study. By comparing Reynolds exponent n of the scaled-up and the scaled-down impellers under adiabatic wall condition, the effect of Reynolds number on scaling of this small scale impeller was studied. The effect of heat transfer was investigated by comparing the results under two different wall conditions (isothermal and adiabatic). This work provides general guidelines for performing scaling designs for small scale centrifugal impellers.

Design and Aerodynamic Performance Investigations of Centrifugal Compressor for 150kW Class Supercritical Carbon Dioxide Simple Brayton Cycle

2020 ◽  
Author(s):  
Run Cao ◽  
Zhigang Li ◽  
Qinghua Deng ◽  
Jun Li
Keyword(s):  
Carbon Dioxide ◽  
Physical Properties ◽  
Centrifugal Compressor ◽  
Flow Condition ◽  
Flow Region ◽  
Aerodynamic Performance ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Brayton Cycle ◽  
Isentropic Efficiency

Abstract The centrifugal compressor is the key component to improve the SCO2 cycle efficiency. In this paper, according to 150kW class supercritical carbon dioxide (SCO2) simple Brayton cycle, a centrifugal compressor with rotating speed 60000r/min is designed. For the small-scale SCO2 centrifugal compressor, the impeller tip clearance loss accounts for most of the aerodynamic loss. Therefore, the designed compressor performance is numerically studied by the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and k-ε (Extended Wall Function) turbulence model. The large variations in physical properties for SCO2 near the critical make simulation be difficult to convergence. To keep the numerical stability and accuracy, 400 × 400 resolution physical properties tables are adopted by the physical properties tables verification. The designed SCO2 centrifugal compressor is with the isentropic efficiency of 73.2% and the pressure ratio of 2.207 under the design flow condition, and good off-design conditions performance are obtained. Compared to the flow condition without the impeller tip clearance, the isentropic efficiency of designed compressor decreases by 14%. For the impeller tip clearance leakage flow, the flow can be divided into three regions, the separation flow region which is along the mainstream flow direction, the back flow region which occupies the top of the impeller tip clearance and the downstream flow region which occupies the bottom of the impeller tip clearance. These flow phenomena and their causes are analyzed. The obtained results reveal that the designed centrifugal compressor meets the requirement of the aerodynamic performance for the 150kW class simple Brayton cycle. The detailed flow pattern of the designed SCO2 centrifugal compressor with consideration of the impeller tip leakage flow is also illustrated.

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.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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