Unsteady Acoustic Forcing on an Impeller Due to Coupled Blade Row Interactions

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Simon K. Richards ◽  
Kishore Ramakrishnan ◽  
Chingwei M. Shieh ◽  
François Moyroud ◽  
Alain Picavet ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Oil And Gas ◽  
Acoustic Analysis ◽  
Pressure Ratio ◽  
Centrifugal Impeller ◽  
Acoustic Excitation ◽  
Wake Interaction ◽  
Blade Row ◽  
Acoustic Forcing ◽  
Return Channel

This article contains an investigation of the unsteady acoustic forcing on a centrifugal impeller due to coupled blade row interactions. Selected results from an aeromechanical test campaign on a GE Oil and Gas centrifugal compressor stage with a vaneless diffuser are presented. The most commonly encountered sources of impeller excitation due to upstream wake interaction were identified and observed in the testing campaign. A 30/rev excitation corresponding to the sum of upstream and downstream vane counts caused significant trailing edge vibratory stress amplitudes. Due to the large spacing between the impeller and the return channel vanes, this 30/rev excitation was suspected to be caused by an aero-acoustic excitation rather than a potential disturbance. The origin of this aero-acoustic excitation was deduced from an acoustic analysis of the unsteady compressor flow derived from CFD. The analysis revealed a complex excitation mechanism caused by impeller interaction with the upstream vane row wakes and subsequent acoustic wave reflection from the downstream return channel vanes. The findings show it is important to account for aero-acoustic forcing in the aeromechanical design of low pressure ratio centrifugal compressor stages.

Unsteady Acoustic Forcing on an Impeller Due to Coupled Blade Row Interactions

2010 ◽  
Author(s):  
Simon K. Richards ◽  
Kishore Ramakrishnan ◽  
Chingwei M. Shieh ◽  
Franc¸ois Moyroud ◽  
Alain Picavet ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Oil And Gas ◽  
Acoustic Analysis ◽  
Pressure Ratio ◽  
Centrifugal Impeller ◽  
Acoustic Excitation ◽  
Wake Interaction ◽  
Blade Row ◽  
Acoustic Forcing ◽  
Return Channel

This article contains an investigation of the unsteady acoustic forcing on a centrifugal impeller due to coupled blade row interactions. Selected results from an aeromechanical test campaign on a GE Oil and Gas centrifugal compressor stage with a vaneless diffuser are presented. The most commonly encountered sources of impeller excitation due to upstream wake interaction were identified and observed in the testing campaign. A 30/rev excitation corresponding to the sum of upstream and downstream vane counts caused significant trailing edge vibratory stress amplitudes. Due to the large spacing between the impeller and the return channel vanes, this 30/rev excitation was suspected to be caused by an aero-acoustic excitation rather than a potential disturbance. The origin of this aero-acoustic excitation was deduced from an acoustic analysis of the unsteady compressor flow derived from CFD. The analysis revealed a complex excitation mechanism caused by impeller interaction with the upstream vane row wakes and subsequent acoustic wave reflection from the downstream return channel vanes. The findings show it is important to account for aero-acoustic forcing in the aeromechanical design of low pressure ratio centrifugal compressor stages.

The influence of the trailing edge angle of the micro centrifugal impeller on the performance of the centrifugal compressor

2021 ◽  
pp. 1-15
Author(s):  
Xu Yu-dong ◽  
Li Cong ◽  
Lv Qiong-ying ◽  
Zhang Xin-ming ◽  
Mu Guo-zhen
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Centrifugal Impeller ◽  
Centrifugal Compressors ◽  
Trailing Edge ◽  
Sweep Angle ◽  
Impeller Blade ◽  
Bending Angle ◽  
Edge Angle ◽  
Isentropic Efficiency

In order to study the effect of the trailing edge sweep angle of the centrifugal impeller on the aerodynamic performance of the centrifugal compressor, 6 groups of centrifugal impellers with different bending angles and 5 groups of different inclination angles were designed to achieve different impeller blade trailing edge angle. The computational fluid dynamics (CFD) method was used to simulate and analyze the flow field of centrifugal compressors with different blade shapes under design conditions. The research results show that for transonic micro centrifugal compressors, changing the blade trailing edge sweep angle can improve the compressor’s isentropic efficiency and pressure ratio. The pressure ratio of the compressor shows a trend of increasing first and then decreasing with the increase of the blade bending angle. When the blade bending angle is 45°, the pressure ratio of the centrifugal compressor reaches a maximum of 1.69, and the isentropic efficiency is 67.3%. But changing the inclination angle of the blade trailing edge has little effect on the isentropic efficiency and pressure ratio. The sweep angle of blade trailing edge is an effective method to improve its isentropic efficiency and pressure ratio. This analysis method provides a reference for the rational selection of the blade trailing edge angle, and provides a reference for the design of micro centrifugal compressors under high Reynolds numbers.

Paper 20: Application of Non-Steady Flow in a Rotating Duct to Pulsating Flow in a Centrifugal Compressor

1967 ◽  
Vol 182 (8) ◽  
pp. 184-196 ◽  
Author(s):  
R. S. Benson ◽  
A. Whitfield
Keyword(s):  
Boundary Condition ◽  
Steady Flow ◽  
Centrifugal Compressor ◽  
Pressure Loss ◽  
Pressure Ratio ◽  
Computer Calculation ◽  
Design Tool ◽  
Centrifugal Impeller ◽  
Vaneless Diffuser ◽  
Flow Equations

This paper deals with a theoretical approach to study the non-steady flow and wave action in a centrifugal impeller and vaneless diffuser, and also to predict the non-steady flow performance of a centrifugal compressor. This was carried out by replacing the compressor unit by a model which consisted of a simplified rotating duct, a vaneless diffuser, and a cone-shaped pipe which replaced the scroll. A theoretical technique using the method of characteristics and the development of the non-steady flow equations to a rotating duct and radial diffuser is given. The development of the theory and the difficulties encountered are described. In particular, the techniques developed for starting a computer calculation are described. In order to maintain homentropic flow in the impeller and diffuser all losses were assumed to occur at the impeller inlet. A pressure loss boundary condition was developed to enable the steady pressure ratio-mass flow characteristics to be computed. When these values agreed with the experimentally determined characteristics, the boundary condition at the rotor inlet was such that the pressure loss terms allowed for the impeller and diffuser losses. The theoretical results obtained are compared with corresponding experimental results, and the possibility of using this theoretical technique as a design tool is discussed.

Centrifugal Compressor Blade Trimming for a Range of Flows

2001 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Centrifugal Compressor ◽  
Test Performance ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Flow Capacity ◽  
Component Test ◽  
Compressor Performance ◽  
Stage Efficiency

Centrifugal impeller blade trimming has long been used in the turbocharger industry to adapt a single impeller casting to a series of flow capacities, but surprisingly little published literature exists on the effects of trimming to compressor performance. This paper is presented as partial remedy, and describes the performance characteristics of a single stage centrifugal compressor designed and tested to cover a range of flow requirements by impeller blade and diffuser vane trimming. Stage and component test performance characteristics are presented for five trimmed flowpath contours covering a flow capacity range of approximately five to one at a DeLaval number of 0.75. The impeller tip diameter was 356mm, and the highest overall stage efficiency measured was 84.8% at an (air) pressure ratio of 1.5.

Measured Performance of Two-Stage Centrifugal Compressor Under Wet Gas Conditions

2012 ◽  
Author(s):  
Matteo Bertoneri ◽  
Simone Duni ◽  
David Ransom ◽  
Luigi Podestà ◽  
Massimo Camatti ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Oil And Gas ◽  
Pressure Ratio ◽  
Oil And Gas Industry ◽  
Liquid Volume ◽  
Performance Measurements ◽  
Two Stage ◽  
Gas Industry ◽  
Discharge Temperature ◽  
Wet Gas

The oil and gas industry is moving forward to access the most remote gas reserves and enhance the exploitation of the existing installation or postponing their tail-end. To achieve these accomplishments several technology challenges are being unveiled. In topside upstream application both offshore and onshore, one important technology issue is the capability to compress gas with a significant amount of liquids and it assumes a special interest in case of the facilities revamping. Nevertheless is in the subsea environment where this technology issue becomes really challenging. In order to properly design and size a compressor/motor system for subsea wet gas compression, one must be able to adequately predict the compressor performance with mixed phase flow. This paper presents the results from an experimental test program which investigated the performance of a centrifugal compressor at various wet gas conditions with elevated suction pressure. Performance tests are completed on a two stage centrifugal compressor with a mixture of air and water at suction pressures of 20 bar (300 psi). The compressor is subjected to flow with liquid volume fractions ranging from 0 to 5% along three speedlines. The performance measurements are made in accordance with ASME PTC-10 specifications with an additional torque measurement on the shaft between the compressor and gearbox. At each test condition, once the liquid is injected in the air flow, an increase in pressure ratio occurs. This testifies the compressor is still able to work in presence of water. However, increasing the amount of liquid injected a decreased polytropic head together with an increased absorbed actual power by the compressor cause a deterioration of its efficiency. Moreover when liquid is introduced into the flow, the discharge temperature of the compressor reduces significantly. The performance results and trends mentioned above are reviewed in the detail in this paper.

Multi-Blade Row Interactions in a Low Pressure Ratio Centrifugal Compressor Stage With a Vaned Diffuser

2011 ◽  
Author(s):  
Kishore Ramakrishnan ◽  
Simon K. Richards ◽  
Franc¸ois Moyroud ◽  
Vittorio Michelassi
Keyword(s):  
Centrifugal Compressor ◽  
Oil And Gas ◽  
Pressure Ratio ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Vaned Diffuser ◽  
Centrifugal Compressor Stage ◽  
Acoustic Interaction ◽  
Field Excitation

Previous experimental and CFD investigation of a GE Oil and Gas centrifugal compressor stage with a vaneless diffuser revealed a complex excitation mechanism caused by an aero-acoustic interaction between three blade rows. In stages with vaned diffusers, additional sources of aeromechanical excitation on the impeller can be expected. This unsteady CFD investigation is a follow-up from the previous vaneless diffuser study to identify any additional sources of excitation that arise in the presence of a vaned diffuser in preparation for aeromechanic tests to be conducted later. The study confirms that excitation from impeller-diffuser interaction generated acoustic modes can dominate the potential field excitation from the diffuser vanes. In addition, a significant aero-acoustic excitation to the impeller at a vane pass frequency corresponding to the sum of the vane counts in the two downstream vane rows is observed, and its origination is discussed. The latter excitation is different from that observed in the vaneless diffuser stage where the vane pass frequency observed by the impeller corresponds to the sum of the vane counts in the upstream and downstream vane rows.

Wet Gas Compressor Operation and Performance

2018 ◽  
Author(s):  
Martin Bakken ◽  
Tor Bjørge ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
Pressure Ratio ◽  
Petroleum Industry ◽  
Open Loop ◽  
Gas Production ◽  
Test Facility ◽  
Operating Point ◽  
Centrifugal Impeller ◽  
Liquid Content ◽  
Wet Gas

The continuous demand for oil and gas forces the petroleum industry to develop new and cost-effective technologies to increase recovery from new fields and enhance extraction from existing fields. Subsea wet gas compression stands out as a promising solution for increasing production capacity, utilizing remote regions and reducing costs. A prerequisite for successful oil and gas production utilizing subsea wet gas compressors is operability. This includes the system’s ability to cope with operational changes, without having to shut down. One of the fundamental operational changes is the liquid content in the inlet pipe, which may fluctuate considerably at certain time intervals. The current study investigates how changes in liquid content impacts compressor performance. An experimental test campaign has been performed at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a symmetrical circular volute. The main objectives were to document how the presence of liquid impacts the compressor characteristics and further, how the operating point moves within the characteristics when solely subjected to an increase of liquid content. The compressor was exposed to liquid contents ranging from gas mass fraction 1.0 to 0.60. The test reveals that the compressor pressure ratio at wet conditions is higher in comparison to dry conditions. Care should be taken when analysing stability and surge margins at variations in fluid liquid content. Further, the compressor behaves in a predictable manner, revealing several linear trends, when subjected to stepwise changes in liquid content from a fixed operating point.

Numerical Studies on Application of Blended Blade and Endwall Technique on Transonic Centrifugal Compressor

2014 ◽  
Author(s):  
Weilin Yi ◽  
Zhi-min Chen ◽  
Lucheng Ji
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Measurement Data ◽  
Centrifugal Impeller ◽  
Aerodynamic Load ◽  
Detailed Measurement ◽  
Uniform Value ◽  
Numerical Studies ◽  
Transonic Centrifugal Compressor

With the continuous improvement of pressure ratio and efficiency in centrifugal compressors, the aerodynamic load is increased significantly. Some unnoticed tiny structures are found having notable influence on centrifugal compressor performance, for example, corners profile between the end walls and the blades. Aiming at this problem, the present paper mainly focuses on the applicability of Blended Blade and EndWall (BBEW) design on the transonic centrifugal compressor. Firstly the Krain transonic impeller is chosen and the predicted flow field is compared with detailed measurement data using commercial CFD code Numeca. The results show that the overall performances are consistent and the details of flow fields are captured accurately. Then a series of uniform value fillets along streamwise are implemented to the hub of transonic centrifugal impeller. The numerical tests show that the aerodynamic performance is deteriorated with the augment of fillets radius, but it seems that adding fillet to the hub of splitter blade can brought positive and negative returns at the same time. Next, as a preliminary original work, a kind of simple Blended Blade and EndWall (BBEW) design which adapt variable radius distribution fillets along streamwise are implemented to the hub of the impeller. Through designing different configurations, the authors find that the performances of some impellers designed by BBEW can be not only higher than impellers with uniform value fillets, but higher than original impeller slightly. In addition, some results are presented on the comparison of flow field structures in different impellers.

Experimental and Numerical Investigations on a High Pressure Ratio Centrifugal Compressor

2005 ◽  
Author(s):  
Jae Ho Choi ◽  
Ok Suck Sung ◽  
Seung-Bae Chen ◽  
Jin Shik Lim
Keyword(s):  
Centrifugal Compressor ◽  
Performance Test ◽  
Pressure Ratio ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Design Flow ◽  
Tip Clearance ◽  
Centrifugal Impeller ◽  
Compressor Stage

An aerodynamic design, flow analysis and performance test of a pressure ratio 4:1 centrifugal compressor are presented in this paper. The compressor is made up of a centrifugal impeller, a two-stage diffuser consisted of radial and axial types. The impeller has a 45 degree backswept angle and the design running tip clearance is 5% of impeller exit height. Two types of diffusers are designed for this compressor. Three-dimensional numerical analysis is performed to analyze the flows in the impeller, diffuser and deswirler considering the impeller tip clearance. A test module and rig facilities for the compressor stage performance test are designed and fabricated. The overall compressor stage performances as well as the static pressure fields on the impeller and diffuser are measured. Two diffusers of wedge and airfoil types are tested with an impeller. The calculation and test results show the airfoil diffuser has the better aerodynamic characteristics than those of wedge diffuser in the studied models.

An Experimental Investigation on the Clocking Effect Between Inlet Guide Vanes and Vaned Diffuser in a Centrifugal Compressor Stage

2008 ◽  
Author(s):  
Jiang Hua ◽  
Xi Guang ◽  
Zhang Wei ◽  
WuQi Gong ◽  
ZhiHeng Wang
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Centrifugal Impeller ◽  
Vaned Diffuser ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Stage Efficiency ◽  
Peak Value

Different circumferential angle positions between stator or rotor vane rows in turbomachinery can lead to different flow structures or stage performances. The clocking effect phenomenon has been detected in axial compressor and turbine by investigators, but rarely reported on centrifugal compressor. The present work is an experimental investigation on the stator clocking effect between inlet guide vanes (IGV) and vaned diffuser in a low-speed centrifugal compressor. The experimental rig consists of a circumferentially rotatable IGV, an unshrouded centrifugal impeller, a vaned diffuser, a volute and etc. The impeller diameter is 796mm, and the rotate speed is about 3100 rpm. At each inlet prewhirl angle of −20°, 0° and +20°, the stage performance curves are measured at three clocking angle positions of 0°, 8° and 16°. The result shows that at the circumferential angles of 0° and 8°, the efficiency curve has a double peak value feature, but at the angle of 16° being the conventional single peak value curve. Further, at the circumferential angles of 0° and 8°, the stage efficiency is bigger 3.6% than that case of the angle being 16°, where the IGV prewhirl angles are 0° and 20°. When the IGV prewhirl angle is changed into −20°, the stage efficiency increases about 2.0% near the first peak value position at the circumferential angles of 0°and 8° than at 16°, however, at the second peak value position, the stage efficiency at the circumferential angle of 0° is bigger about 1.4% than at 8° and 16°. Moreover, the circumferential angle positions between IGV and vaned diffuser have corresponding influence on the pressure ratio.

Sign in / Sign up

Export Citation Format

Share Document