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Aeroelastic Analysis of Preset Angle for A Typical Airfoil Section with Cubic Nonlinear Stiffness

Journal of Physics: Conference Series 2019年第1期1300卷

作者： Guofang Nan Di Ding Weitao Wang School of Energy and Power Engineering University of Shanghai for Science and Technology China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering 516 Jungong Road 200093 Shanghai P.R. China

The influences of the preset angle on the dynamic responses of the typical airfoil section with cubic nonlinear stiffness were investigated under consideration of the aerodynamic flutter onset due to certain angle of attack. The typical airfoil model with cubic nonlinear stiffness is developed to analyze the plunging and the pitching motions for the airfoil section. Based on the Grossman's quasi steady aerodynamic model, the aerodynamic lift and the moment can be obtained and then the equation of motion for the airfoil section is derived by applying the Lagrange theorem. The effects of the preset angle and the oncoming flow speed on the nonlinear dynamics are analyzed by means of the bifurcation diagram, the frequency-amplitude diagram, the time history, etc. Simulation results show that the preset angle influences the intensity of the vibration, moderate or severe, stable or unstable, even under certain circumstance, the jump and chaos phenomenon occur; and the oncoming flow speed affects the distribution of the vibration energy for the plunging and the pitching motions. The unstable stall region for the responding parameters should be avoided to keep the airfoil safe in engineering practice. Some qualitative and quantitative rules are obtained for the airfoil design and the flutter suppression.

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New insights into aerodynamic characteristics of oscillating wings and performance as wind power generator

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INTERNATIONAL JOURNAL OF ENERGY RESEARCH 2018年第2期42卷 776-789页

作者： Sun, Xiaojing Zhang, Laichao Huang, Diangui Zheng, Zhongquan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Kansas Dept Aerosp Engn Lawrence KS 66045 USA

In this paper, the effects of nondimensional frequency f*, pitch amplitude (0), and airfoil thickness on the energy extraction performance of an oscillating wing wind power generator were numerically investigated. It is found that the optimum value of f* or theta(0) exists to achieve the maximum energy efficiency. Additionally, the thickness of airfoil also significantly affects the efficiency and the flow patterns around the oscillating foil. For thin airfoils, a relatively large-scale vortex was normally generated at its leading edge. This vortex detached from leading edge might be able to be caught by the airfoil again and then reutilized to increase its work capacity. By contrast, no induced leading edge vortex is formed on the upper surface of a thick airfoil. Nevertheless, the pressure difference between the upper and lower surface of the oscillating thick airfoil is greater than that of thin airfoil. Thus, the portion of the output power contributed by the oscillatory heaving motion is greatly increased and high energy extraction efficiency can still be achieved. For airfoils with moderate thickness, both flow phenomena observed on thin and thick oscillating airfoils that have high wind energy utilization efficiency are all likely to occur, depending on the adopted motion parameters.

关键词： energy extraction efficiency numerical study oscillating-wing wind power generators performance affecting factors

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Effect of environmental pressure on heat and mass transfer characteristics for fin-and-tube heat exchangers under non-unit Lewis factor

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APPLIED THERMAL engineering 2017年 116卷 784-791页

作者： Liu Qi Liu Jianhua Zhang Liang Xu Xiaojin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China CSIC Res Inst 704 Shanghai 200031 Peoples R China

The heat and mass transfer characteristics for fin-and-tube heat exchangers with low environmental pressures have been experimentally investigated. The variation trends of the j(h) factor, In factor and Lewis factor were examined in this study when environmental pressure decreases from 101.3 to 40 kPa. The errors caused by non-unit Lewis factor when calculating the total heat transfer rate using the logarithmic mean enthalpy difference (LMED) method were discussed. It was found that the inlet humidity ratio for the incoming air is inversely proportional to environmental pressure under the experimental conditions. Both the heat and mass transfer performances decrease when the environmental pressure is reduced. However, the j(m) factor shows a transient rise when Re < 1100. Test results show that the heat and mass transfer analogy is roughly applicable, and the Lewis factor is in the range of 0.73-0.96. The maximal relative deviation of the total heat transfer rate calculated by the LMED method is about 18.7%. However, a modified LMED (m-LMED) method can describe the total heat transfer rate within 3.8%. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Environmental pressure heat transfer Mass transfer Lewis factor LMED

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Experimental study on multi-stage gas-liquid booster pump for working fluid pressurization

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APPLIED THERMAL engineering 2017年 126卷 9-16页

作者： Wu, Tengma Liu, Jianhua Zhang, Liang Xu, Xiaojin Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China CSIC Res Inst 704 Shanghai 200031 Peoples R China

To improve the performance of organic Rankine cycle (ORC) system, this paper proposes to replace the electric working fluid pump with multi-stage gas-liquid booster pump which is driven by high pressure gas generated in evaporator of ORC system. This pump consists of four gas-liquid booster pumps. The working principle of gas-liquid booster pump and multi-stage gas-liquid booster pump are introduced respectively. By using high pressure air as driving force and water as pressurized working fluid, the performance of multi-stage gas-liquid booster pump is tested experimentally. The experimental results of this study mainly consist of two parts: the first part focuses on the pump performance with various pressure at pump inlet and outlet while valve at pump inlet is completely open;the second part focuses on various valve open ratio at pump inlet which is operated at fixed inlet and outlet pressure of 1.8 MPa and 0.15 MPa. The results show that the pump conversion efficiency decreases with the increase of inlet pressure and the decrease of outlet pressure. The maximum conversion efficiency, volume flow rate of water and volume flow rate of high pressure air are 0.72, 0.55 L/s and 0.42 L/s respectively. When the pump is operated at different valve open ratio, the volume flow rate of water and high pressure air decreases with the decrement of valve open ratio. In addition, the conversion efficiency almost maintains identical under different valve open ratio. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Organic Rankine cycle Pump power Multi-stage gas-liquid booster pump Conversion efficiency

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Direct Simulation Monte Carlo Method for Acoustic Agglomeration under Standing Wave Condition

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AEROSOL AND AIR QUALITY RESEARCH 2017年第4期17卷 1073-1083页

作者： Fan, Fengxian Zhang, Mingjun Peng, Zhengbiao Chen, Jun Su, Mingxu Moghtaderi, Behdad Doroodchi, Elham Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Newcastle Sch Engn Discipline Chem Engn Callaghan NSW 2308 Australia

Acoustic agglomeration proves promising for preconditioning fine particles (i.e., PM2.5) as it significantly improves the efficiency of conventional particulate removal devices. However, a good understanding of the mechanisms underlying the acoustic agglomeration in the standing wave is largely lacking. In this study, a model that accounts for all of the important particle interactions, e.g., orthokinetic interaction, gravity sedimentation, Brownian diffusion, mutual radiation pressure effect and acoustic wake effect, is developed to investigate the acoustic agglomeration dynamics of PM2.5 in the standing wave based on the framework of direct simulation Monte Carlo (DSMC) method. The results show that the combination of orthokinetic interaction and gravity sedimentation dominates the acoustic agglomeration process. Compared with Brownian diffusion and the mutual radiation pressure effect, the acoustic wake plays a relatively more important role in governing the particle agglomeration. The phenomenon of particle agglomeration becomes more pronounced when the acoustic frequency and intensity are increased. The model is shown to be capable of accurately predicting the dynamic acoustic agglomeration process in terms of the detailed evolution of particle size and spatial distribution, which in turn allows for the visualization of important features such as "orthokinetic drift". The prediction results are in good agreement with the experimental data.

关键词： Fine particles (PM2.5) Acoustic agglomeration Standing wave Direct simulation Monte Carlo (DSMC) method Numerical simulation

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Effect of Guide Vanes on flow and Vibroacoustic in an Axial-flow Pump

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MATHEMATICAL PROBLEMS IN engineering 2018年第1期2018卷

作者： Li, Guoping Chen, Eryun Yang, Ailing Xie, Zhibin Zhao, Gaiping Shanghai Marine Equipment Res Inst Shanghai 200031 Peoples R China Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Sch Med Instruments & Food Engn Shanghai 200093 Peoples R China

An effect of guide-vane numbers on pressure fluctuations and structural vibroacoustics induced by unsteady flow is performed by a hybrid numerical method. A 3D flow field is simulated in axial-flow pump with four impeller blades, in which three diffuser models with 5, 7, and 9 vanes are devised to match, respectively. A full scale structural vibroacoustics coupled model is solved using LMS acoustics software. The results show that the blade-passing frequency (BPF) is dominated frequency of the vibration acceleration of pump, which is consistent with frequency spectral characteristics of pressure pulsation. The unsteady pressure fluctuating becomes strong as the flow discharge decreases from 1.0Qv to 0.6Qv, the circumferential unsteady behavior of which is more severe due to flow nonuniformity induced by the suction elbow at partial operation. Generally, the pressure fluctuating increases slightly when the flow discharge increases from 1.0Qv to 1.3Qv. Moreover, pressure fluctuations amplitude on the pump with 9-vane diffuser is small relative to other two models and the vibrating accelerating and radiation sound field at BPF are also slight relatively, which indicates that appropriate guide-vane numbers contribute to suppress pressure fluctuations and vibroacoustics in axial-flow pwnp. 'I he conclusions in the present paper can provide theoretical guidance for low vibration pump design.

关键词： Acoustic fields

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A DEM Analysis of Particle Climbing in a Vibrating Pipe 7th

A DEM Analysis of Particle Climbing in a Vibrating Pipe

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7th International Conference on Discrete Element Methods (DEM)

作者： Fan, F. X. Liu, J. Su, M. X. Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China

ISBN: (纸本)9789811019265;9789811019258

Recent experiments have shown that when a vertical pipe is inserted into a box filled with granular material and is then set into vertical vibration, the particles may undergo climbing motion along the pipe. However, this phenomenon, which may provide efficient means for transportation of particulates in industrial applications, is still poorly understood. Therefore, here we describe a computational study of particle climbing in a vibrating pipe inserted into a static granular box using the discrete element method (DEM). We reproduce the process of particle climbing, and give the evolution of particle climbing height with time, the motion of individual particles with different initial positions, and the void filling effect of the particles from the silo into the pipe. Based on this, the mechanisms underlying the particle climbing are analyzed.

关键词： Finite difference method

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Numerical simulation of flow characteristics for a labyrinth passage in a pressure valve

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Journal of Hydrodynamics 2016年第4期28卷 629-636页

作者：王海民赵越汪建兴孔祥帅刘欢李科良王喜芳 School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology

A tortuous labyrinth passage consists of a series of right angle turns in a disk of high pressure control *** this paper,numerical simulations are made for the velocity and pressure distributions in this *** is shown that the “series passage” can induce a pressure dropping more *** main function of the “series passage” is to induce a pressure dropping while the “parallel passage” is mainly to regulate the *** a cross sectional area process,a series of reduction and expansion,the pressure will also see dropping and partial recovery,which is called the multistage pressure *** this way,the velocity can be controlled in a reasonable level anywhere in this tortuous labyrinth *** the fluid pressure dropping in a downwards serrated way,the pressure is higher than the local saturate vapor pressure,therefore,no cavitation is induced by the phase transition.

关键词： passage valve dropping multistage turns sectional anywhere regulate vortex inlet

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An LP-DOAS Instrument with a Laser Driven Light Source for Open-path Measurement of Atmospheric NO₂ in shanghai

An LP-DOAS Instrument with a Laser Driven Light Source for O...

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Progress in Electromagnetics Research Symposium - Spring (PIERS)

作者： Li, Mingzhi Chen, Jun Su, Mingxu Yang, Huinan Ramachandran, Arun Varma, Ravi Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China Natl Inst Technol Calicut Dept Phys Calicut Kerala India

ISBN: (纸本)9781509062690

shanghai is currently faced with the complex atmospheric pollution problem such as ozone (O-3) and PM2.5. O-3 is responsible for oxidization of atmospheric constituents that in turn produces secondary pollutants. Reducing atmospheric oxidation is the underpinning strategy for the prevention and control of pollution in this city. According to the observation data from the online automatic monitoring station of shanghai, the city's O-3 concentration has been rising steadily. In 2013, there are 100 days with ozone as the main pollutants, accounted for 31.9%. By Leighton relationship (K-6[O-3][NO]/K-4[NO2] = 1), concentration of O-3 is closely related to that of NO2. So, continuous monitoring of atmospheric NO2 has important significance. An instrument was developed for measuring atmospheric NO2 concentration using a powerful light source in conjunction with the long-path differential optical absorption spectroscopy (LP-DOAS) technique. This system installed at the central section of shanghai used a laser driven light source (LDLS) and a sensitive TE cooled apectrometer. The LDLS showed better stability, high optical efficiency when compared to traditional arc lamp and light emitting diodes. The light sent into the atmosphere was returned by a retroreflecting mirror placed 1.3 km away, and the light returned was sent to a high sensitive TE cooled spectrometer. The spectral range of measurement was 415-455 nm and the spectra collected were averaged over 10 min, prior to analyzing for NO2 concentration. Continuous observations were carried out for two weeks and the NO2 concentration retrieved ranged from (20-600) ug/m(3) with an estimated detection limit of 6.77 ug/m(3). The measurement results indicate that it is feasible to use this instrument for detecting the NO2 with high spatial and temporal sensitivity.

关键词： Absorption Atmospheric measurements Light sources Pollution measurement Optical sensors Wavelength measurement Instruments

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Simulation of natural convection in an inclined polar cavity using a finite-difference lattice Boltzmann method

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JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2017年第6期31卷 3053-3065页

作者： Yang, Fan Yang, Haicheng Yan, Yonghua Guo, Xueyan Dai, Ren Liu, Chaoqun Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Alcorn State Univ Dept Math & Comp Sci Lorman MS 39096 USA Univ Texas Arlington Dept Math Arlington TX 76019 USA

Natural convection heat transfer in an inclined polar cavity was studied using a Finite-difference lattice Boltzmann method ( FDLBM) based on a double-population approach for body-fitted coordinates. A D2G9 model coupled with the simplest TD2Q4 lattice model was applied to determine the velocity field and temperature field. For both velocity and temperature fields, the discrete spatial derivatives were obtained by combining the upwind scheme with the central scheme, and the discrete temporal term is obtained using a fourth-order Runge-Kutta scheme. Studies were carried out for different Rayleigh numbers and different inclination angles. The results in terms of streamlines, isotherms, and Nusselt numbers explain the heat transfer mechanism of natural convection in an inclined polar cavity due to the change of Rayleigh number and inclination angle.

关键词： Body-fitted coordinates Finite-difference LBM Natural convection Inclination Polar cavity Rayleigh-Benard convection

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