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Numerical and experimental comparison of the vaned diffuser interaction inside the impeller velocity field of a centrifugal pump

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Science China(Technological Sciences) 2011年第2期54卷 286-294页

作者： ATIF Abdelmadjid BENMANSOUR Saad BOIS Gerard DUPONT Patrick Laboratory of Advanced Mechanics FGMGP/USTHBBP32 El Alia16111AlgerAlgeria Laboratory of Mechanics of Lille ENSAM-Lille8 Bd Louis XIV59046LilleFrance Laboratory of Mechanics of Lille EC-LilleBP48 Villeneuve d’Ascq59651LilleFrance

The paper refers to the analysis of interactions between the impeller and the vaned diffuser based on the air model of a radial flow *** study deals with a numerical simulation of the flow for a full 360°entire impeller and *** task is carried out closely under the design operating conditions and for one particular position of the impeller blade with respect to the diffuser *** all the results,the focus is mainly on the flow pattern at the exit part inside the impeller facing the diffuser *** results are compared to the available PIV measurements.

关键词： centrifugal pump impeller vaned diffuser rotor-stator interaction

Numerical Investigation of Rotating Stall in Centrifugal Compressor with vaned and Vaneless diffuser

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Journal of Thermal Science 2015年第4期24卷 323-333页

作者： Taher Halawa Mohamed Alqaradawi Mohamed S.Gadala Ibrahim Shahin Osama Badr Mechanical Engineering Department UBC-University of British ColumbiaVancouverB.C.Canada Mechanical Engineering Department Cairo University Mechanical & Industrial Engineering Department Qatar University Mechanical Engineering Department Abu Dhabi University Mechanical and Industrial Engineering Department Qatar UniversityDohaQatar Mechanical Engineering Department Benha University Mechanical Engineering Department British University

This study presents a numerical simulation of the stall and surge in a centrifugal compressor and presents a description of the stall development in two different *** first case is for a compressor with vaneless diffuser and the second is for a compressor with vaned diffuser of the vane island *** main aim of this study is to compare the flow characteristics and behavior for the two compressors near the surge operating condition and provide further understanding of the diffuser role when back flow occurs at *** showed that for a location near the diffuser entrance,the amplitude of the static pressure fluctuations for the vaneless diffuser case is higher than that for the vaned diffuser case near surge *** pressure fluctuations in the case of the vaneless diffuser appear with a gradual decrease of the mean pressure value as a part of the surge *** for the case of the vaned diffuser,the pressure drop during surge occurs faster than the case of the vaneless ***,results indicated that during surge in the case of vaneless diffuser,there is a region with low velocity and back flow that appears as a layer connecting all impeller passages near shroud surface and this layer develops in size with *** the other hand,for the case of vaned diffuser during surge,the low velocity regions appear in random locations in some passages and these regions expand with time towards the shroud *** showed that during stall,the impeller passages are exposed to identical impact from stall cells in the case of vaneless diffuser while the stall effect varies from passage to another in the case of the vaned diffuser.

关键词： centrifugal compressors rotating stall surge vaneless diffuser vaned diffuser

Effect of high negative incidence on the performance of a centrifugal compressor stage with conventional vaned diffusers

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Journal of Thermal Science 2011年第2期20卷 97-105页

作者： Ahti Jaatinen Aki Grnman Teemu Turunen-Saaresti Jari Backman Lappeenranta University of Technology

Three vaned diffusers, designed to have high negative incidence (-8°) at the design operating point, are studied experimentally. The overall performance (efficiency and pressure ratio) are measured at three rotational speeds, and flow angles before and after the diffuser are measured at the design rotational speed and with three mass flow rates. The results are compared to corresponding results of the original vaneless diffuser design. Attention is paid to the performance at lower mass flows than the design mass flow. The results show that it is possible to improve the performance at mass flows lower than the design mass flow with a vaned diffuser designed with high negative incidence. However, with the vaned diffusers, the compressor still stalls at higher mass flow rates than with the vaneless one. The flow angle distributions after the diffuser are more uniform with the vaned diffusers.

关键词： centrifugal compressor vaned diffuser efficiency performance flow field

Aerodynamic Performance and Noise Characteristics of a Centrifugal Compressor with Modified vaned diffusers

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Journal of Thermal Science 2006年第4期15卷 289-295页

作者： YutakaOHTA YasuhikoOKUTSU TakashiGOTO EisukeOUTA Department of Mechanical Engineering Waseda University3-4-1 OkuboShinjukuTokyo 169-8555Japan

Improvement of aerodynamic performance and reduction of interaction tone noise of a centrifugal compressor with vaned diffusers are discussed by experiments and visualization techniques using a colored off-film method. The focus of the research is concentrated on the leading edge shape of diffuser vanes that are deeply related to the generation mechanism of the interaction tone noise. The compressor-radiated noise can be reduced by more than ten decibels by using modified diffuser vanes which have 3-D tapered shapes on both pressure and suction sur- faces of the leading edge. Furthermore, by adopting the proposed modified diffuser vanes, the secondary flow which is considered to be an obstruction of diffuser pressure recovery can be suppressed, and also the pressure decrease observed in the throat part of the diffuser flow passage is reducible. Thus, the proposed diffuser vanes show a favorable result for both noise and the aerodynamic performance of the centrifugal compressor, and offer a few basic guidelines for the diffuser vane design.

关键词： centrifugal compressor vaned diffuser tapered diffuser vanes noise reduction

Unstable Head-Flow Characteristic Generation Mechanism of a Low Specific Speed Mixed Flow Pump

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Journal of Thermal Science 2006年第2期15卷 115-120,144页

作者： Masahiro MIYABE Hideaki MAEDA Isamu UMEKI Yoshinori JITTANI Department R & D Torishima Pump Mfg. Co. Ltd. 1-1-8 Miyata-cho Takatsuki-shi Osaka 569-8660 JAPAN

This paper treats the flow instabilities in a mixed flow pump with a vaned diffuser. Test pump has a positive slope of a head-flow performance curve at 65% flow rate of BEP (Best Efficiency Point) because of a rotating stall. Dynamic Particle Image Velocimetry (PIV) and pressure fluctuation measurements are used for investigating the propagation mechanism of a rotating stall. It was found that unstable performance was caused by periodical large scale abrupt backflow generated from the vaned diffuser to the outlet of impeller. Further, the relation between the static pressure at the inlet of diffuser vane and the internal flow condition was clarified. From these experimental results, in order to improve the positive slope of a head-flow performance curve, to suppress the growth of strong vortex toward the inlet of diffuser vane was proved to be a key point.

关键词： mixed flow pump vaned diffuser flow instabilities rotating stall dynamic PIV

Effects of diffuser Vane Geometry on Interaction Noise Generated from a Centrifugal Compressor

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Journal of Thermal Science 2005年第4期14卷 321-328页

作者： Yutaka OHTA Naho TAKEHARA Yasuhiko OKUTSU Eisuke OUTA Department of Mechanical Engineering Waseda University 3-4-1 Okubo ShinjukuTokyo 169-8555Japan

The characteristics of interaction tone noise radiated from a centrifugal compressor with a vaned diffuser are discussed by experiments, including visualization techniques using the oil-film method. Research attention is paid to the leading edge geometries of the diffuser vanes that are deeply related to the generation mechanism of the interaction tone noise. The compressor-radiated noise can be reduced by several decibels by setting some clearances in both the hub and shroud surfaces of the diffuser wall along with some decline in the pressure-rise coefficient. Since the decline turned out to be caused by the flow impingement and also by the secondary flow within the diffuser passages, several new types of diffuser vane geometries which do not detract from both the performance and noise level are developed and utilized for the experiments. The presented diffuser vane geometries will offer a few basic guidelines for the diffuser vane design.

关键词： centrifugal compressor vaned diffuser interaction noise noise reduction.