Experimental and Numerical Verification of Effect of Using Curvilinear Element Blades for Low-Solidity Cascade Diffuser in Centrifugal Compressor

2017 ◽  
Author(s):  
Kazuhiro Tsukamoto ◽  
Kiyotaka Hiradate ◽  
Kiyohide Sakamoto ◽  
Yasushi Shinkawa
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Recirculation Region ◽  
Numerical Verification ◽  
Two Dimensional ◽  
Suction Surface ◽  
Design Point ◽  
Operating Range ◽  
Setting Angle ◽  
Low Solidity Cascade Diffuser

The effect of using curvilinear element blades (CEBs) on a low-solidity cascade diffuser (LSD) in a centrifugal compressor was investigated both experimentally and numerically. Centrifugal compressors require a higher efficiency and wider operating range to reduce the lifecycle costs of plants in which they are used and the effects their users have on the environment. A LSD has a wider operating range than a common vaned diffuser that has high solidity, but worse efficiency at the design point. For this reason, this research aims to improve the efficiency of the LSD and keep its operating range wide without changing the blade setting angle or two-dimensional geometry. As a first step, LSDs with three different curvilinear element profiles were compared with a conventional LSD, and the mechanism of the performance improvement was investigated by using a numerical simulation. These diffusers have the same two-dimensional geometry, blade setting angle, and number of blades but different blade stacking geometry in the span-wise direction. Unsteady Reynolds Averaged Navier-Stokes (RANS) simulations were conducted using a one-blade path model with an inlet, impeller, and LSD diffuser passages. The LSD using the CEBs improved the efficiency by 1.9% over that of the conventional LSD at the design point while maintaining the same operating range. The calculation results reveal that the recirculation region decreased at the suction surface of the diffuser vane in the CEB case and the diffuser efficiency improved. The concaved suction surface increased the blade loading and induced higher velocity on the suction surface. The higher velocity prevented reverse flow on the suction surface at the hub side, and the secondary flow removed the thick boundary layer at the trailing edge to the downstream of the diffuser. Experimental verification was also conducted using a single-stage compressor with an impeller, diffuser, and scroll casing to verify the prediction. The experimental results showed the LSD using the CEB has a higher pressure rise at the stator region than the conventional LSD and verified the performance improvement due to using the CEBs.

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

1986 ◽  
Author(s):  
H. Harada
Keyword(s):  
Centrifugal Compressor ◽  
Closed Loop ◽  
Three Dimensional ◽  
Performance Characteristics ◽  
Working Fluid ◽  
Angle Distribution ◽  
Two Dimensional ◽  
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 working fluid was employed for the experiments. The inlet and outlet velocity distribtions of all impellers were measured using three hole cobra probes. As a result, it has been revealed that three-dimensional impellers are superior to two-dimensional one 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.

scholarly journals Centrifugal Compressor Performance Improvement through Multi Splitter Impeller

2019 ◽  
Vol 26 (2) ◽  
pp. 6-14
Author(s):  
Adil Malik ◽  
Qun Zheng ◽  
Shafiq R. Qureshi ◽  
Salman A. Ahmed ◽  
D. KB Gambo
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Suction Surface ◽  
Pressure Surface ◽  
Percent Increase ◽  
Compressor Performance ◽  
Overall Performance ◽  
Total Pressure Ratio

Abstract In the paper, a back swept impeller of centrifugal compressor is experimentally studied and numerically validated and modified to increase its pressure ratio and improve efficiency, as well as to analyse the effect of splitter blade location between two main blades. The back swept multi splitter blade impeller was designed with a big splitter positioned close to the main blade suction surface and a smaller splitter close to the pressure surface. Adding this multi splitter improves the overall performance of the modified impeller due to less intensive flow separation and smaller pressure loss. In particular, the total pressure ratio was observed to increase from 4.1 to 4.4, with one percent increase in efficiency.

Effect of double splitter blades position in a centrifugal compressor impeller

2018 ◽  
Vol 233 (6) ◽  
pp. 689-701
Author(s):  
Adil Malik ◽  
Qun Zheng
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Surface Flow ◽  
Flow Conditions ◽  
Suction Surface ◽  
Pressure Surface ◽  
Compressor Impeller ◽  
Novel Design ◽  
Total Pressure Ratio

This paper reveals a novel design of centrifugal compressor impeller with multisplitter blades for performance improvement. In order to investigate the effects of the location of the splitter between two main blades, two sample impellers were designed, keeping all flow conditions and impeller definitions same as the experimentally validated impeller: (1) with big splitter close to suction surface of main blade and smaller splitter close to pressure surface; (2) with small splitter close to suction surface of main blade and big splitter close to pressure surface. Flow field in both the impellers is analyzed and compared with the original experimentally validated impeller. Total pressure ratio is increased with improved efficiency in multisplitter blade impellers with the addition of pair of big and small splitters blades. It was identified that small splitter close to the suction surface of the main blade and big splitter close to the pressure surface has more uniform flow, reduced separation, and better efficiency than the placement of big splitter close to the suction surface.

Metamodel-driven data mining model to support three-dimensional design of centrifugal compressor stage

2021 ◽  
pp. 1-63
Author(s):  
Qin Ruihong ◽  
Yaping Ju ◽  
Stephen W T Spence ◽  
Chuhua Zhang
Keyword(s):  
Data Mining ◽  
Performance Improvement ◽  
Centrifugal Compressor ◽  
High Efficiency ◽  
Three Dimensional ◽  
Great Effort ◽  
Operating Range ◽  
Geometry Parameter ◽  
Mining Model ◽  
Wide Operating

Abstract The design of a centrifugal compressor with high efficiency and a wide operating range is a challenging task. A great effort has been undertaken to solve the three-dimensional design problem with the assistance of a metamodel. However, the published works lack any study that systematically performs the data mining between the performance and three-dimensional geometry variation due to two unsolved issues, i.e., lack of reliable systematic data mining model and unresolved high-dimensional data problem in the centrifugal compressor community. To tackle these issues, a systematic metamodel-driven data mining model including six general modules has been proposed and implemented to the well-known Radiver stage. In this data mining task, four specific techniques were used to go through the general to specific data mining. The results showed the performance improvement probabilities, the trade-off relationships between performance parameters, the characteristic variation of the performance, and the correlations between performance and the most sensitive two geometry parameter variation. The appropriate variation ranges for wide operating range design of the two sensitive geometry parameters were recommended and the flow mechanism behind them was clarified. The statistical results showed that over 90% of the design stages in the recommended variation ranges had a wide operating range. A design case was chosen randomly in the recommended range to verify the performance improvement via CFD simulations. The outcomes of this work are particularly relevant for the advanced design of compressors with high efficiency and a wide operating range for flexibility.

Performance Improvement of Centrifugal Compressor Impellers by Optimizing Blade-Loading Distribution

2008 ◽  
Author(s):  
Manabu Yagi ◽  
Tadaharu Kishibe ◽  
Takanori Shibata ◽  
Hideo Nishida ◽  
Hiromi Kobayashi
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Design Procedure ◽  
Blade Loading ◽  
Operating Range ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Cfd Analyses ◽  
Suction Flow

The improvement of efficiency and operating range by optimizing blade-loading distribution of three-dimensional (3D) centrifugal compressor impellers is investigated using computational fluid dynamics (CFD) analyses and performance tests. The design points of suction flow coefficients investigated in the present study were 0.05 and 0.073. Two design approaches for 3D impeller were employed: a conventional method and a newly developed one. In order to achieve higher efficiency and wider operating range, the blade loading and relative velocity distribution were optimized in the new design procedure. In addition, to clarify the performance improvement of 3D impellers against current two-dimensional (2D) ones, both performance characteristics were compared. The test results showed the efficiencies of the newly designed 3D impellers were increased by about 0.5–1.5% in comparison with those of the conventional impellers, while the operating ranges of both were almost the same. Further, the efficiencies of the newly designed 3D impellers increased by about 3% in comparison with those of the 2D impellers at both design points. At the same time, the operating ranges of the former impellers were about 2.1–2.8 times as wide as those of the latter.

An Airfoil Diffuser With Variable Stagger and Solidity for Centrifugal Compressor Applications

2007 ◽  
Author(s):  
Ahmed Abdelwahab
Keyword(s):  
Centrifugal Compressor ◽  
High Performance ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Two Dimensional ◽  
Compressor Stage ◽  
Operating Range ◽  
Compressor Impeller ◽  
Dimensional Variable ◽  
Wide Operating

Airfoil diffusers have been extensively used in industrial centrifugal compressors. However, the majority of these diffusers are two-dimensional and have fixed solidity. This paper presents a numerical investigation of a new three-dimensional airfoil diffuser, i.e. variable stagger, which has a varying solidity in the span wise direction. The premise of this configuration is to better align the diffuser blade with the non uniform flow leaving the compressor impeller as well as to combine the benefits of the known wide operating range of the low solidity diffusers with the high performance of the high solidity diffusers. Numerical simulations of several impeller-diffuser configurations are presented. The first configuration uses a three-dimensional variable solidity airfoil diffuser while the others use conventional diffusers with different solidities. The results of the simulations are presented in terms of the aerodynamic performance of both the impeller and diffusers as well as the overall stage performance. The analysis indicates that the three dimensionality of the flow path of the proposed diffuser greatly impacts the diffuser as well as the impeller aerodynamic performance. The analysis also indicates the superiority of the proposed new diffuser geometry over the analyzed conventional airfoil diffusers in extending the operating range of the compressor stage as well as improving its efficiency.

Analysis of vortices and performance of different diffusers in a large mass flow coefficient centrifugal compressor

2017 ◽  
Vol 231 (4) ◽  
pp. 253-273 ◽  
Author(s):  
Peng-Fei Zhao ◽  
Yan Liu ◽  
Xiao-Fang Wang
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
Large Mass ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Suction Surface ◽  
Tip Leakage ◽  
Centrifugal Compressor Stage ◽  
Operating Range ◽  
Surface Vortex

An appropriate diffuser following an impeller is critical to realize a high efficiency and a wide operating range for a centrifugal compressor stage. The purpose of this study is to investigate the effect of different types of vaned diffusers on a large mass flow coefficient centrifugal compressor stage performance under different operating conditions and to reveal the loss mechanisms in the vaned diffusers. Five vaned diffusers are studied. Flow fields and vortices in a conventional diffuser and a rib diffuser are first examined. Then, vortices and flow fields in three different tandem diffusers are analyzed in detail. For the three tandem diffusers, only circumferential position of first row vanes relative to the second row vanes is different. Results show that the stage with the conventional diffuser possesses the shortest operating range. The rib diffuser has less loss due to the weaker tip leakage vortex, while its static pressure recovery coefficient is lower, and the loss in the following return part is higher. Comparison results between the three tandem diffusers imply that when the trailing edge of the first row vane is close to the pressure surface of the second row vane, the stage with the tandem diffuser has a better performance. This is ascribed to the interaction of the tip leakage vortex and suction surface vortex, which decreases the total loss, especially reduces the loss induced by the suction surface vortex. When the trailing edge of the first row vanes is close to the suction surface of the second row vane, the loss is increased since the leading edge vortex has a large strength and surrounds the suction surface vortex. Therefore, the reasonable interaction of vortices in a tandem diffuser can bring a high performance of the centrifugal compressor.

Performance improvement of inverted two-dimensional perovskite solar cells using a non-fullerene acceptor as the trap passivator

2021 ◽  
Author(s):  
Eun-Cheol Lee ◽  
Zhihai Liu
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Performance Improvement ◽  
High Power ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Two Dimensional ◽  
High Power Conversion Efficiency ◽  
Long Term Stability

Recently, Ruddlesden–Popper two-dimensional (2D) perovskite solar cells (PSCs) have been intensively studied, owing to their high power conversion efficiency (PCE) and excellent long-term stability. In this work, we improved the...

Effect of Vaned Diffuser on a Modified Turbocharger Centrifugal Compressor Performance

2014 ◽  
Vol 663 ◽  
pp. 347-353
Author(s):  
Layth H. Jawad ◽  
Shahrir Abdullah ◽  
Zulkifli R. ◽  
Wan Mohd Faizal Wan Mahmood
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Width Ratio ◽  
Outlet Section ◽  
Suction Surface ◽  
Vaned Diffuser ◽  
Minimum Width

A numerical study that was made in a three-dimensional flow, carried out in a modified centrifugal compressor, having vaned diffuser stage, used as an automotive turbo charger. In order to study the influence of vaned diffuser meridional outlet section with a different width ratio of the modified centrifugal compressor. Moreover, the performance of the centrifugal compressor was dependent on the proper matching between the compressor impeller along the vaned diffuser. The aerodynamic characteristics were compared under different meridional width ratio. In addition, the velocity vectors in diffuser flow passages, and the secondary flow in cross-section near the outlet of diffuser were analysed in detail under different meridional width ratio. Another aim of this research was to study and simulate the effect of vaned diffuser on the performance of a centrifugal compressor. The simulation was undertaken using commercial software so-called ANSYS CFX, to predict numerically the performance charachteristics. The results were generated from CFD and were analysed for better understanding of the fluid flow through centrifugal compressor stage and as a result of the minimum width ratio the flow in diffuser passage tends to be uniformity. Moreover, the backflow and vortex near the pressure surface disappear, and the vortex and detachment near the suction surface decrease. Conclusively, it was observed that the efficiency was increased and both the total pressure ratio and static pressure for minimum width ratio are increased.

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