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Prediction of gas pulsation of an industrial compressor

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Journal of Central South University 2013年第10期20卷 2735-2740页

作者： Heuicheol Kim Mi-Gyung Cho Jaehong Park Cheolho Bai Jaesool Shim School of Mechanical Engineering Yeungnam University Department of Media Engineering Tongmyong University MEMS-Bio Team Korea National NanoFab Center 305 806 Korea

The measurement and prediction of gas pulsations are performed along the discharge pipeline of a reciprocating compressor for a refrigerator. A regression based experimental model of the one-dimensional acoustic field is developed. First, the conventional method for gas pulsation measurement and prediction, which separates the incident and reflected wave of acoustic waves traveling in the frequency domain, is discussed. Then, regression based on our proposed simple model, which is able to predict gas pulsation compared to the conventional method, is introduced for the analysis of a reciprocating compressor(The conventional method requires the value of sound speed in the piping line for the reciprocating compressor). A numerical prediction is made for the regression method. Three power spectrum values along the discharge pipeline are used for analysis, and two values are used for verification. Our results are in a good agreement with the conventional method.

关键词： gas pulsation reciprocating compressor discharging piping line regression model

Deformation pre-compensated optimization design of cam ring for low pulsation hydraulic motors

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第2期24卷 130-145页

作者： Chao ZHANG Hao TAN Yu FANG Xiaolong ZHANG Yu YANG Yiman DUAN Min HAN Shaojian CUI Bing XU Junhui ZHANG State Key Laboratory of Fluid Power and Mechatronic Systems Department of Mechanical EngineeringZhejiang UniversityHangzhou 310058China Zenmax Hydraulics Co. Ltd.Qinhuangdao 066000China

Cam-lobe radial-piston hydraulic motors are widely used in large machinery due to their excellent capability to withstand high loading at low ***,the line contact between the roller and cam ring generates elastic deformation of the cam ring under high loading,leading to obvious speed and torque pulsations and even the detrimental crawl problem of hydraulic *** address this issue,we propose a deformation pre-compensated optimization design approach to compensate for the cam ring deformation in advance,thereby eliminating the influence of cam ring deformation on the hydraulic motor’s *** this approach,the design process is divided into two steps:first,the overall profile of the cam ring is optimized based on the calculated elastic deformation;second,the local profile of cam ring is further optimized until the hydraulic motor’s pulsations no longer ***,a case study is carried out to verify the effectiveness of this *** result indicates the pulsation rate of a deformation pre-compensated cam ring is 40%lower than that of an uncompensated *** study offers an easy and feasible way to design an optimized cam ring profile for low pulsation hydraulic motors.

关键词： Hydraulic motors Cam ring Deformation pre-compensation pulsation

FREQUENCY　DOMAIN　ANALYSIS　AND　COMPUTER　SIMULATION　OF　PRESSUREpulsation　RESONANCE　IN　HIGHPRESSURE　PIPI

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Chinese Journal of Mechanical Engineering 1994年第1期7卷 40-48页

作者： Yan Siangan Zheng Wei Lei Kangbin Cao YupingTianjing University

The characteristics of the pressure pulsation resonance in HP fluid piping networks have been researched by means of computer simulation. It can be used as an auxiliary means to acquaint the effects of the structural parameters of complex fluid pipelines. It has provided the basis for reasonably configurating pipelines and avoiding the pressure pulsation resonance in fluid pipelines. It is of great applied value to engineering.

关键词： Fluid piping network Pressure pulsation Resonance Simulation

Pulsatory characteristics of wind velocity in sand flow over typical underlying surfaces

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Science China Earth Sciences 2007年第2期50卷 247-253页

作者： ZHANG KeCun QU JianJun ZU RuiPing FANG HaiYan Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China

Pulsatory characteristics of wind velocity in sand flow over Gobi and mobile sand surface have been investigated experimentally in the wind tunnel. The primary goal of this paper is to reveal the relation- ship between pulsatory characteristics of instantaneous wind speed in sand flow and the motion state of sand grains. For a given underlying surface, pulsation of wind velocities in sand flow on different heights has a good correlation. As the space distance among different heights increases, fluctuation of instantaneous wind speed presents a decreasing trend and its amplitude is closely related to the mo- tion state of sand grains and their transport. Pulsatory intensity increases with the indicated wind speed, but its relative value does not depend on it, only agrees with height.

关键词： underlying surface sand flow pulsation of wind speed

Study on Unstable Characteristics of Centrifugal Pump under Different Cavitation Stages

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Journal of Thermal Science 2019年第4期28卷 608-620页

作者： DONG Liang SHANG Huanhuan ZHAO Yuqi LIU Houlin DAI Cui WANG Ying Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China

In order to reveal the regularity of unsteady flow of centrifugal pump under different cavitation stages,a visual closed test-bed is built to collect signals such as the distribution of cavitation bubbles at the impeller inlet and external characteristics,*** the process of cavitation of centrifugal *** with the shape and distribution of bubbles captured by high-speed photography,the cavitation stage of the centrifugal pump is *** addition,the variation of vorticity distribution,pressure pulsation and radial force of centrifugal pump under different cavitation stages are studied using the standard κ-ε turbulence model and the Kunz cavitation *** contributions are as follows:The cavitation bubbles can absorb the energy of vortex core to a certain extent and increase the volume of vortex *** bubbles can also block the flow-path and induce the distortion of the internal flow field,resulting in unstable pressure waves that cause a significant increase in pressure pulsation ***,with the development of cavitation,the radial force on the impeller tends to remain invariable first and then decrease,and trajectory of the radial force changes from closed to open.

关键词： centrifugal pump cavitation development stage cavitation bubble distribution pressure pulsation radial force

Investigation on reversible pump turbine flow structures and associated pressure field characteristics under different guide vane openings

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Science China(Technological Sciences) 2019年第11期62卷 2052-2074页

作者： BINAMA Maxime SU WenTao CAI WeiHua LI FengChen WEI XianZhu MUHIRWA Alex GONG RuZhi WEKESA David W School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Energy and Power Shenyang Institute of Engineering Shenyang 110136China School of Energy and Power Engineering Northeast Electric Power UniversityJilin 132012China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China State Key Laboratory of Hydropower Equipment Harbin Institute of Large Electric MachineryHarbin 150040China

The use of reversible pump turbines(RPT) within pumped storage power plants goes with prolonged periods of off-design operating conditions, which leads to the onset of operating mode-dependent instabilities. In order to decrease the gravity of RPT flow instabilities and associated damages or even completely eliminate them, a deep understanding of its onset and development mechanism is needed. In line with this, the present study seeks to numerically investigate the onset and development mechanism of RPT unsteady flow structures as well as the evolutional characteristics of associated pressure pulsations throughout the RPT complete flow passage, under off-design conditions for three GVOs namely 17, 21, and 25 mm. The study results showed that low torque operating conditions and associated vaneless space back flow structures were the trigger of flow unsteadiness onset within the RPT vaneless space, the instabilities which grew to cause the S-shape characteristics appearance. Moreover, the runner flow unsteadiness was found to decrease with the GVO increase. On the other hand, the GVO increase worsened the pressure pulsation levels within RPT flow zones, where pressure pulsations within the vaneless space and flow zones in its vicinities were found to be the most sensitive to GVO changes.

关键词： reversible pump-turbine flow unsteadiness pressure pulsation guide vane opening numerical simulation

Hydraulic piston pump in civil aircraft: Current status, future directions and critical technologies

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Chinese Journal of Aeronautics 2020年第1期33卷 16-30页

作者： Shengrong GUO Jinhua CHEN Yueliang LU Yan WANG Hongkang DONG Nanjing Engineer Institute of Aircraft System Jincheng AVICNanjing 211100China Aviation Science and Technology Key Laboratory of Aero Electromechanical System Integration Nanjing 211100China School of Transportation Science and Engineering Beihang UniversityBeijing 100083China

The piston pump is the key power component in the civil aircraft hydraulic system,and the most common pump used in the aviation field is the pressure compensated variable displacement *** this review paper,a basic introduction to the civil aircraft piston pump is presented,including the classification,structure,working principle,design features,and achievements by some research ***,the future directions of the aircraft pump are reported from various ***,the critical technologies are analyzed and summarized in detail from six thrust areas:friction couples,noise reduction,inlet boost,thermal management,fault diagnosis and health management,and mechanical ***,the challenges and limitations of the research on the aircraft pump are discussed to provide valuable insight for future scholars.

关键词： Civil aircraft Engine driven pump High pressure Inlet boost Intelligent control Lubricating gaps Piston pumps pulsation reduction

Energy Loss Analysis of Novel Self-Priming Pump Based on the Entropy Production Theory

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Journal of Thermal Science 2019年第2期28卷 306-318页

作者： CHANG Hao SHI Weidong LI Wei LIU Jianrui Research Center of Fluid Machinery Engineering and Technology Jiangsu University School of mechanical engineering Nantong University

The conventional method cannot explicitly confirm the location and type of the energy loss, therefore this paper employs the entropy production theory to systematically analyze the category, magnitude and location of hydraulic loss under different blade thickness distribution. Based on the analysis, the turbulent entropy and viscosity entropy produced by the separation of boundary layer at the trialing edge are major factors leading to the hydraulic loss. In addition, the separation of the boundary layer can not only cause the energy loss, but also block the passage of the impeller and reduce the expelling coefficient of the blade. Therefore, the hydraulic performance of the blades with increment thickness distribution is obviously better than the decrement one. Further, the flow rate has different influence on the three types of entropy production. Meanwhile, the pressure pulsation on the working surface was investigated. It was concluded that with flow rates increasing, the amplitude of pressure pulsation firstly decreases and then smoothly improves, and reaches the minimum under design flow rate. Finally, the optimal blade was obtained, and the relevant hydraulic performance test was performed to benchmark the simulation result. This research can provide the theoretical reference for designing the reasonable thickness distribution of the blades.

关键词： entropy production energy loss thickness distribution pressure pulsation

Power characteristics of a variable hydraulic transformer

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Chinese Journal of Aeronautics 2015年第3期28卷 914-931页

作者： Yang Guanzhong Jiang Jihai Department of Fluid Power Control and Automation Harbin Institute of Technology

Abstract The flow control of hydraulic transformers is a great challenge. To meet this challenge, a new kind of hydraulic transformer, variable hydraulic transformer （VHT）, is proposed in this work. This paper focuses on the power characteristics of the newly proposed VHT, including instanta neous power, average power, power pulsation, and efficiency. In the analyses, the concepts of efficiency, input power, output power, starting angle, and ceasing angle are defined or redefined. To investigate the power characteristics, their models are derived by considering the governing fac tors such as the control angle of the swash plate and the structure of the port plate. This work high lights that the load flow can be adjusted by adjusting the control angle of the swash plate, and the power characteristics at the Bport produce a remarkable change. In addition, the VHT has a starting angle and a ceasing angle, and these two angles can be adjusted by the influencing factors. The results reveal that the power pulsation and the jump points of the instantaneous power are the primary causes of a less smooth work. Then, it is shown that the control angle of the port plate, the control angle of the swash plate, and the pressures at the ports are the three key elements for a stable operation. The results also reveal that the adjustment of the influencing factors can improve the efficiency.

关键词： Aircraft Efficiency Energy-saving Hydraulic transformerPower pulsation Stable operation