Numerical Investigation of Different Casing Treatments on Performance of a High Speed Centrifugal Compressor Stage

2011 ◽  
Author(s):  
Yan Ma ◽  
Guang Xi ◽  
Guangkuan Wu
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
High Speed ◽  
The Other ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Centrifugal Compressor Stage ◽  
And Performance ◽  
Casing Treatments

In this paper, two different casing treatment devices—one adopting inlet recirculation at the shroud side of the impeller inlet and the other adopting circumferential casing grooves at the shroud side of the vaneless space, are designed for a high speed centrifugal compressor stage. The effects of different casing treatments to the flow range and performance of the centrifugal compressor stage are studied numerically. The results indicate that traditional inlet recirculation at impeller inlet does not extend the stall margin of the stage and the performance deteriorates due to the adding of the extra device. The study also shows that, when the location of the bleed slot moves downstream, the performance of the stage deteriorates due to the longer flow path. Moreover, the 2mm depth circumferential casing grooves extend the stall margin by about 12.05%. By contrast, the 6mm depth and 10mm depth grooves extend the stall margin by 3% and 2.4% respectively.

Experimental Validation of a Wide-Range Centrifugal Compressor Stage for Supercritical CO2 Power Cycles

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Timothy C. Allison ◽  
Natalie R. Smith ◽  
Robert Pelton ◽  
Jason C. Wilkes ◽  
Sewoong Jung
Keyword(s):  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Successful Implementation ◽  
Compressor Stage ◽  
Test Results ◽  
Power Cycles ◽  
Casing Treatment ◽  
Centrifugal Compressor Stage ◽  
Operating Range ◽  
Wide Range

Successful implementation of sCO2 power cycles requires high compressor efficiency at both the design-point and over a wide operating range in order to maximize cycle power output and maintain stable operation over a wide range of transient and part-load operating conditions. This requirement is particularly true for air-cooled cycles where compressor inlet density is a strong function of inlet temperature that is subject to daily and seasonal variations as well as transient events. In order to meet these requirements, a novel centrifugal compressor stage design was developed that incorporates multiple novel range extension features, including a passive recirculating casing treatment and semi-open impeller design. This design, presented and analyzed for CO2 operation in a previous paper, was fabricated via direct metal laser sintering and tested in an open-loop test rig in order to validate simulation results and the effectiveness of the casing treatment configuration. Predicted performance curves in air and CO2 conditions are compared, resulting in a reduced diffuser width requirement for the air test in order to match design velocities and demonstrate the casing treatment. Test results show that the casing treatment performance generally matched computational fluid dynamics (CFD) predictions, demonstrating an operating range of 69% and efficiency above air predictions across the entire map. The casing treatment configuration demonstrated improvements over the solid wall configuration in stage performance and flow characteristics at low flows, resulting in an effective 14% increase in operating range with a 0.5-point efficiency penalty. The test results are also compared to a traditional fully shrouded impeller with the same flow coefficient and similar head coefficient, showing a 42% range improvement over traditional designs.

scholarly journals Flow mechanism of affecting an axial flow compressor performance and stability with cross-blade slot casing treatments

2018 ◽  
Vol 233 (1) ◽  
pp. 17-36 ◽  
Author(s):  
HaoGuang Zhang ◽  
XuDong Zhang ◽  
YanHui Wu ◽  
WuLi Chu ◽  
HaiYang Kuang
Keyword(s):  
Axial Flow ◽  
Low Energy ◽  
Peak Efficiency ◽  
Stall Margin ◽  
Casing Treatment ◽  
Flow Loss ◽  
Stall Margin Improvement ◽  
And Performance ◽  
Flow Compressor ◽  
Casing Treatments

The objective of this study is to evaluate the effect of cross-blade slot casing treatment on the stability and performance of an axial flow compressor rotor. The experimental and unsteady calculated results both show that cross-blade slot casing treatment can generate about 22% stall margin improvement, and the compressor peak efficiency is reduced by about 13%. The detailed flow-field analyses indicate that the sucked and injected flow caused by the slots of cross-blade slot casing treatment can restrain the rotor tip passage blockage, which is made by the low energy tip clearance leakage vortex. When cross-blade slot casing treatment is applied, not only the rotor wheel flange work becomes lower in most of the rotor blade span, but also the flow loss in the blade tip passage becomes fairly large due to the strong interaction between the mainstream and the injected flows made by the slots. As a result, the compressor total pressure ratio and efficiency for cross-blade slot casing treatment are reduced obviously. Three kinds of new cross-blade slot casing treatment were designed according to the previous successful experience and investigated in this paper. The numerical results show that the new three cross-blade slot casing treatments both generate about 54% stall margin improvement at the cost of minor peak efficiency. For one new cross-blade slot casing treatment (CSCT2), the compressor peak efficiency is reduced by about 0.3%. The low energy TLV, which is present for cross-blade slot casing treatment, is removed by the strong sucked flow made by CSCT2. Moreover, the interaction between the mainstream and the injected flows caused by CSCT2 becomes weak obviously, and the corresponding flow loss is reduced greatly. Hence, the compressor stability and performance with CSCT2 are higher than those with cross-blade slot casing treatment.

Laser Transit Anemometry Investigation of a High Speed Centrifugal Compressor

1989 ◽  
Author(s):  
David Japikse ◽  
David M. Karon
Keyword(s):  
Experimental Investigation ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Turbulence Intensity ◽  
High Speed ◽  
Flow Regimes ◽  
Compressor Stage ◽  
Blade Passage ◽  
Centrifugal Compressor Stage

A detailed experimental investigation of a small centrifugal compressor stage has been completed using laser transit anemometry. Measurements at the inlet and discharge of an impeller have been made while recording data relative to a blade passage. Classical primary and secondary flow regimes within the rotor have been shown plus several compact “cell-like” regions. Various components of velocity and turbulence intensity are presented. This study has demonstrated the capability of using the laser transit anemometer for investigating the kinematics of small, high speed turbomachinery components.

Experimental and Numerical Investigation of Tip Clearance and Bleed Effects in a Centrifugal Compressor Stage With Pipe Diffuser

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Robert Kunte ◽  
Philipp Schwarz ◽  
Benjamin Wilkosz ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Tip Clearance ◽  
Compressor Stage ◽  
Local Flow ◽  
Centrifugal Compressor Stage ◽  
Centrifugal Stage ◽  
Flow Phenomena ◽  
Fundamental Insight ◽  
The Impact

The subject of this paper is the experimental and numerical investigation of a state-of-the-art high pressure centrifugal compressor stage with pipe diffuser for a jet engine application. This study shows the impact of impeller tip clearance- and bleed-variation on the centrifugal stage. The purpose of this paper is threefold. In the first place, it investigates the effects on the stage performance. Secondly, it seeks to explain local flow-phenomena, especially in the diffuser. Finally, it shows that steady CFD simulations are capable of predicting these phenomena. Experimental data were gathered using conventional pitot and three-hole-probes as well as particle-image-velocimetry. Numerical simulations with the CFD solver TRACE were conducted to get fundamental insight into the flow. Thus, this study contributes greatly towards understanding the principle of the flow phenomena in the pipe diffuser of a centrifugal compressor.

Numerical investigation & comparison of a tandem-bladed turbocharger centrifugal compressor stage with conventional design

2014 ◽  
Vol 23 (6) ◽  
pp. 523-534
Author(s):  
Syed Noman Danish ◽  
Shafiq Rehman Qureshi ◽  
Abdelrahman EL-Leathy ◽  
Salah Ud-Din Khan ◽  
Usama Umer ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Conventional Design

Numerical investigation of a highly loaded centrifugal compressor stage with a tandem bladed impeller

2017 ◽  
Vol 232 (3) ◽  
pp. 240-253 ◽  
Author(s):  
Ziliang Li ◽  
Xingen Lu ◽  
Yanfeng Zhang ◽  
Ge Han ◽  
Chengwu Yang ◽  
...  
Keyword(s):  
Flow Structure ◽  
Centrifugal Compressor ◽  
Compressor Stage ◽  
Suction Surface ◽  
Flow Angle ◽  
Flow Solver ◽  
Stall Margin ◽  
Centrifugal Compressor Stage ◽  
Compressor Design ◽  
Highly Loaded

This study numerically investigated a highly loaded centrifugal compressor stage with various tandem-designed impellers and a wedge diffuser using a state-of-the-art multi-block flow solver to better understand the fundamental mechanism of tandem impellers. The flow topologies in the impeller are analyzed in detail to identify the underlying physical mechanism of the effect of the tandem-impeller design on the performance of the compressor stage. Particular emphasis is placed on the evolution of the flow structure in the tandem bladed impeller by varying the inducer–exducer clocking arrangements. The results demonstrate that a tandem compressor design is more efficient than a conventional compressor design for the majority of the tested clocking configurations, and the tandem clocking friction significantly affects the impeller performance. For the tested centrifugal compressor stage, an approximately 1.4% increase in isentropic efficiency and 1.3% increase in stall margin are achieved with an inducer–exducer clocking fraction of 25%. The improvement in the primary centrifugal compressor stage performance by the tandem-impeller design is a result of the manipulation of the flow structure and the reduction in the highly distorted jet/wake exit flow pattern. Compared to the conventional impeller designs, the tandem-impeller clocking arrangement variation significantly affects the high-momentum flow along the exducer suction surface and inducer wake diffusion, inlet axial velocity, and flow angle of the exducer blade. Therefore, this variation is advantageous for shortening the length of the boundary layers on both parts of the blade and enables an intense mixing at the exducer passage to improve the flow uniformity of the impeller exit. As a result, the impeller efficiency, diffuser recovery, and stalling margin can be improved compared with the conventional design.

Experimental and Numerical Investigation of the Flow in a Vaneless Diffuser of a Centrifugal Compressor Stage. Part 2: Numerical Investigation

2005 ◽  
Vol 219 (10) ◽  
pp. 1061-1068 ◽  
Author(s):  
T Sato ◽  
J M Oh ◽  
A Engeda
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Centrifugal Compressor Stage ◽  
Improved Performance ◽  
Very High

As user demands grew for improved performance and more reliable equipment and as compressor vendors sought improved analytical and design methodologies, the application of computational fluid dynamics (CFD) in the industrial world became a necessity. Fortunately, large increases in available, economic computing power together with development of improved computational methods now provide the industrial designer with much improved analytic capability. As CFD algorithms and software have continued to be developed and refined, it remains essential that validation studies be conducted in order to ensure that the results are both sufficiently accurate and can be obtained in a robust and predictable manner. Part I of this paper presented detailed flow measurements in a vaneless diffuser of a centrifugal compressor stage with a very high flow coefficient radial impeller, where measurements were carried out in the vaneless diffuser at seven radial positions downstream of the radial impeller designed for a very high flow coefficient of ϕ = 0.2. This paper, Part II, attempts to verify and validate the results numerically.

scholarly journals Flow Field and Performance of a Centrifugal Compressor Rotor With Tandem Blades of Adjustable Geometry

1994 ◽  
Author(s):  
Burkhard Josuhn-Kadner
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Wake Flow ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Compressor Rotor ◽  
Surge Margin ◽  
Bladed Rotor ◽  
And Performance

A centrifugal compressor stage has been investigated mainly experimentally for aerodynamic stage optimization. The rotor consists of a separate inducer with 14 blades and an impeller with 28 blades. Both rotor components can be locked with each other at different circumferential positions thus, forming either a conventional splitter blade rotor or a tandem bladed rotor of adjustable geometry. The influence of the tandem blade geometry on the rotor and stage characteristics is studied in detail. Laser-2-Focus-System measurements were performed at nine locations all over the rotor taking three different circumferential inducer positions into account. The improvement with the tandem blade configuration on the rotor and stage characteristics is small but significant differences in the flow field of the two different impeller channels in the rear and exit part of the rotor are recognizable. The velocity differences of the jet/wake flow are reduced by using tandem blades which lead to a slight increased stage pressure ratio and surge margin.

Experimental and computational investigation of a centrifugal compressor stage

2005 ◽  
Vol 219 (1) ◽  
pp. 25-33 ◽  
Author(s):  
L Gao ◽  
G Xi ◽  
L Zhou ◽  
S Wang
Keyword(s):  
Centrifugal Compressor ◽  
The Other ◽  
Stress Model ◽  
Compressor Stage ◽  
Hot Wire ◽  
Computational Investigation ◽  
Centrifugal Compressor Stage ◽  
Unsteady Effect ◽  
Unsteady Interaction ◽  
Computational Fluid Dynamics Cfd

This paper presents experimental and computational investigations on a centrifugal compressor stage to study unsteady interaction flow and to verify the capability of computational fluid dynamics (CFD) codes. Detailed instantaneous flow has been measured at several different measuring positions using a hot-wire anemometer with the phase-locked ensemble-averaged technique. To describe quantitatively the unsteady effect induced from the impeller, an unsteady intensity is defined in this paper. Also, two computational investigations for the tested centrifugal compressor are performed and compared with corresponding experimental data: one is a steady method with the deterministic stress model and the other is an unsteady method with the sliding interface technique.

Numerical Investigation to Assess the Performance of Free Rotating Vaneless Diffuser for a Centrifugal Compressor Stage

2017 ◽  
Author(s):  
Seralathan Sivamani ◽  
Roychowdhury Dibyakanti Ghosh
Keyword(s):  
Energy Level ◽  
Diffusion Process ◽  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Rotational Speed ◽  
Effective Diffusion ◽  
Stagnation Pressure ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Centrifugal Compressor Stage

Numerical investigation is carried out on a low-pressure ratio centrifugal compressor stage to study the effects of the rotational speed of a rotating vaneless diffuser on flow diffusion using various flow parameters and performance characteristics parameters. The results obtained are compared with a stage having conventional stationary vaneless diffuser. Rotational speed of the rotating vaneless diffuser plays a major role in determining the extent of net gain in energy level of the fluid and drop in stagnation pressure losses. The net gain in energy level result as rise in kinetic energy level of the fluid. By an effective diffusion process, this results into an improved static pressure and stagnation pressure distribution at stage exit and FreeRVDSR0.75 undergoes a comparatively better diffusion process. Based on this study, it can be concluded that the diffusion process efficacy of a compressor stage with rotating vaneless diffuser is better in the free type at diffuser’s rotational speed above 0.50 times the impeller’s rotational speed.

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