Proceedings of the 9th International Conference

on Hydrodynamics (ICHD 2010)

October 11 – 15, 2010,Shanghai, China
Editors: Y. S. Wu, S. Q. Dai, H. Liu, L. D. Zhou, X. C. Yang

Industrial Hydrodynamics (10)

D1-1 An integrated design system for turbomachinery

Xu-wen Qiu, Mark Anderson, David Japikse.

Concepts NREC, 217 Billings Farm Road, White River Junction, VT 05001-9486, USA

Abstract :

This paper outlines an integrated design system for turbomachinery, particularly machines such as gas turbines, hydraulic turbines, pumps, and propellers commonly found in marine operations. The system incorporates flow modeling, structural analysis, and manufacturing simulation under one integrated design environment, which allows effective sharing and transfer of information among different stages and disciplines of the design, thus optimizing the design process. The design starts with 1D meanline modeling, which allows designers to explore a vast design space and produces a basic flow path and preliminary performance prediction. From the meanline results, an initial 3D geometry model can be constructed. This geometry model serves as the core of the design system on which further aerodynamic and mechanical optimization, such as full 3D computational fluid dynamics (CFD) analysis and finite element analysis (FEA), can be subsequently performed. Furthermore, a computer-aided manufacturing (CAM) component is also part of the design system. The early inclusion of 5-axis manufacturing considerations in the design process can help reduce overall costs while avoiding the expensive overhaul of the aerodynamic and structural design late in the process. This integrated approach ensures that the final design not only meets the performance target, but also satisfies the requirements of structural integrity and manufacturability.

D1-2 The profile-linear average velocity for the transition in pipes based on the method of LES.

Yong-hui Liu, Guang-sheng Du, Zheng-gang Liu, li Li, Li-li Tao.

School of energy and power engineering, Shandong University, Jinan, China

Abstract :

The ultrasonic flowmeter has been widely used in the industrial flow measurement. The flow measurement accuracy depends on the relationship of the profile-linear average velocity. But this relationship of the transition zone is not available at present. In this paper, the characteristics of transition flow with specific Re number in pipes are researched. The  εk model  and LES (Large Eddy Simulation) model are respectively used to calculate the flow field of the transition zone, and the experiment results show that the LES model is more effective than the  εk model. The relationship of the profile-linear average velocity for the transition zone in pipes is obtained by the calculated results of the LES model and it is proved that there is a big error using the tradition relationship based on the turbulence flow to calculate the profile-linear average velocity relationship of the transition flow. The research results of this paper can improve the measurement accuracy of ultrasonic flowmeters and provide theoretical basis for the research on the whole transition flow.

D1-3 Aerodynamic study of WIG craft near curved ground

Wei Yang, Cheng-Jiong Ying, Zhi-gang Yang.

Shanghai Automotive Wind Tunnel Center, Tongji University, Shanghai, China.

Abstract :

Wing-In-Ground Effect (WIG) Craft (Russian ekranoplans) offers a new transport solution somewhere between boat and aircraft and may revolutionize the future fast sea transportation in terms of its characteristics. Aerodynamic characteristics of WIG craft near curved ground are investigated. Computational fluids dynamics (CFD) method is applied into the study due to limitation of wind tunnel test in simulating curved ground. Numerical techniques including sliding meshing and dynamic meshing are established and compared in the study to analyze effect of curved ground on WIG craft. Aerodynamics and flow features of WIG craft with and without course angles in cruise are taken into consideration in the current work. The study will hopefully clarify the understanding of the aerodynamics of WIG craft.

D1-4 Well test analysis of viscoelastic polymer solution

Wei-li Yang, Hong-jun Yin, Hui-ying Zhong, Si-yuan Meng.

Key Laboratory of Enhanced Oil and Gas Recovery (Daqing Petroleum Institute), Ministry of Education, Daqing, China.

Abstract :

With the consideration that the polymer solution has the characteristics of viscosity and elasticity, the seepage flow model is established. The model is solved by the finite difference method. Then the type curves are drawn. The influences of the skin factor, the wellbore storage factor, the consistency coefficient, the power law index and the elasticity sensitivity factor of the polymer solution on the type curves are analyzed. This study shows that it is very necessary to consider the elasticity in the well test analysis of viscoelastic polymer solution.

D1-5 An experimental study on leakage flowin different geometrical disk seals

Wei Zhao, Torbjørn K. Nielsen, Jan Tore Billdal

Norwegian University of Science and Technology, Trondheim, Norway.

Abstract :

This paper presents an experimental study on the leakage flow in rotor-stator system. The experimental setup of the rotor-stator system is a simplification of a Francis turbine runner with focus on the seals. It consists of a motor, a bearing, a shaft, a fixed rotor made of steel, a pump and a plastic ring fixed on the steel rotor, which can be replaced with different geometrical pads to test various seals. A small radial clearance (0.2mm) between the rotational disk and stator is settled. Leakage loss, pressure variation under the rotational disk and pressure difference between above and below the disk for various geometrical seals is measured at different rotational speeds. The results indicate that the rotational disk can reduce the leakage loss as the speed increases and the performance of disk without pads is better than the disk with straight pads under the same supply flow.

D2-1 Hydrodynamics of trapezoidal embankment weirs

Xi-kun Wang, Zhi-yong Hao, Soon Keat Tan

Maritime Research Centre,Nanyang Technological University, 50 Nanyang Avenue, Singapore.

Abstract :

This paper presents the results of an experimental study over a 2-dimensional trapezoidal weir model with the upstream and downstream faces sloped at 1:2 (V:H). The flow field has been measured using Particle Image Velocimetry (PIV). Several hydrodynamic properties of the flow, including the different flow regimes, free surface profile, mean and instantaneous velocity fields, and discharge coefficient, are discussed and analyzed.

D2-2 A study on separation performance of a vortex finder in a liquid-liquid cylindrical cyclone

Shi-ying Shi, Ying-xiang Wu, Jun Zhang, Jun Guo, Shu-jing Wang

Institute of Mechanics, Chinese Academy of Sciences, Beijing, China

Abstract :

The paper proposes a methodology within the Reynolds Averaged Navier Stokes (RANS) solvers for cavitating flows capable of predicting the flow regions of bubble collapse and the potential aggressiveness to material damage. An aggressiveness index is introduced, called Cavitation Aggressiveness Index (CAI) based on the total derivative of pressure which identifies surface areas exposed to bubble collapses; the index is tested in two known cases documented in the open literature and seems to identify regions of potential cavitation damage.

D2-3 On studies of formation, diffusion mechanisms and prevention measures of CO during HEGF in low permeability oil reservoirs

Chun-sheng Pu, Peng Rao, Min Zhou, Fei-peng Wu, Wen-long Qin

School of Petroleum Engineering, China University of Petroleum, Dongying, China

Abstract :

High energy gas fracture(HEGF)has been one of central measuresused to increase production and effusion in low permeability reservoirs. But there are some problems of this technology. One of them is that large number of toxic and harmful gases caused by it will trigger severe CO poisoning events. In this paper, the formation-gathering rule and countermeasures of CO for HFGF were studied across-the-board in low permeability reservoirs. The study showed that the primary reasons to produce CO are HEGF itself and that high temperature gases for HEGF reacted with associated gas and oil. At the same time, the formation mechanism of CO was illuminated. The study was of great theoretical value to prevent CO in effect for low permeability reservoirs, and was of great guiding significance for the rational development of similar oilfields.

D2-4 Applied new rotation correction κ-ω SST model for turbulence simulation of centrifugal impeller in the rotating frame of reference

Wei Zhang, Zheng Ma, Yun-Chao Yu, Hong-Xun Chen

Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, China

Abstract :

Based on the analysis of transportation equation of turbulence fluctuant velocity in the rotating frame of reference, it is the first time that the extended intrinsic mean spin tensor is instead of mean vorticity tensor in the well-known Richardson number and applied to improve the A.Hellsten`s correction of system rotation to Menter`s κ−ω SST turbulence model. The modified model is more applicable for turbulence simulation in the rotating frame of reference. It is used for turbulence simulation of flow in the centrifugal pump impeller in this paper. Compared with Menter`s κ−ω SST  and original rotation correction, this model can get better result of effect of system rotation and its induced to the turbulence in the centrifugal impeller.

D2-5 Analysis of oil-lubricated herringbone grooved journal bearing with trapezoidal cross-section, using a spectral finite difference method

Jun Liu, Mochimaru Yoshihiro

Tochigi R&D Center, Keihin-Corp, 2021-8, Hoshakuji Takanezawa-machi, Shioya-gun, Tochigi, Japan

Abstract :

A modified Reynolds equation for an oillubricated journal bearing is derived, including curvature effect under a lubrication theory, and the curvature effect on characteristics of the journal bearing is discussed. In addition, in case of a herringbone-grooved journal bearing with trapezoidal cross-sections, the modified Reynolds equation is solved, using a spectral finite difference method to get characteristics such as variation of load capacity and attitude angle for trapezoidal angles offrom 1.8 through 7.2 degrees.