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Experimental Study on the Characteristics of Liquid Layer and Disturbance Waves in Horizontal annular flow

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Journal of Thermal Science 1999年第4期8卷 235-242页

作者： Li Weidong Zhou Fangde Li Rongxian Zhou Lixing Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China State Key Laboratory of Multiphase flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, using five parallel-wire conductance probes, time records of local liquid film thickness at five circumferential positions were collected. The characteristics of circumferential liquid film thickness profiles and its variation with gas and liquid velocities were obtained. The basic features of probability distribution function, probability density function, auto-correlation, cross-correlation and power spectrum density function of the disturbance waves in angular flow were studied respectively. The characteristics of circumferential profiles of disturbance waves and its variation with gas and liquid velocities were presented.

关键词： two-phase flow annular flow liquid layer disturbance wares.

Numerical Simulation of Aspect Ratio Effect on Turbulent annular flows

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Journal of Energy and Power Engineering 2010年第12期4卷 17-23页

作者： M. Raddaoui Faculty of Science of Gafsa Unit ＂Materials Energy and Renewable energies.＂ MEER ＂ University of Gafsa Zarroug city 2112Gafsa Tunisia

The control of energy in various industrial applications passes by the comprehension of the phenomena of transfers especially in complex flows. The structure of the turbulent flow in the cavities in rotation depends on several parameters like the Reynolds number of rotation Ra and the aspect ratio of the cavity. The purpose of this work is to simulate numerically the effect of the aspect ratio on the level of turbulence in the annular steady flow with an incompressible fluid for three different configurations. In the first, the interior cylinder is fixed and the external is moving. The second configuration is the reverse. The third is the contra-rotating cylinders. For all these configurations, we varied the aspect ratio from 0.5 to 2.5. The numerical tool is based on a statistical model in a point using the closing of the second order of the transport equations of the Reynolds stresses （Reynolds Stress Model： RSM）. The results of our numerical simulation show that this geometrical parameter can be an interesting factor to increase the level of turbulence that is often required in several industrial applications where the economy and the control of energy are always required.

关键词： Energy turbulent flow Reynolds number of rotation aspect ratio of the cavity to simulate annular flow Reynolds Stress Model.

VIBRATION AND STABILITY OF VERTICAL UPWARD-FLUID-CONVEYING PIPE IMMERSED IN RIGID CYLINDRICAL CHANNEL

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Acta Mechanica Solida Sinica 2008年第5期21卷 431-440页

作者： Qin Qian Lin Wang Qiao Ni Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China

A theoretical model is developed for the vibration and stability of a vertical pipe subjected concurrently to two dependent axial flows. The external fluid, after exiting the outer annular region between the pipe and a rigid cylindrical channel, is conveyed upwards inside the pipe. This configuration thus resembles of a pipe that aspirating fluid. The equation of planar mo- tion is solved by means of the differential quadrature method （DQM）. Calculations are conducted for a slender drill-string-like and a bench-top-size system, for different confinement conditions of the outer annular channel. It is shown that the vibrations of these two systems are closely related to the degree of confinement of the outer annular channel. For a drill-string-like system with narrow annuli, buckling instability may occur in the second and third modes. For a bench-top-size system, however, both buckling and flutter may occur in the lowest three modes. The form of instability depends on the annuli size.

关键词： pipe conveying fluid annular flow axial flow drill-string stability critical flow velocity

Condensation Heat Transfer Inside a Tube in a Microgravity Environment

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Journal of Thermal Science 1996年第3期5卷 184-189页

作者： LiuYuke WangWeicheng DepartmentofThermalEngineering TsinghuaUniversityBeijing100084China DepartmentofThermalEngineering

This paper introduces a method for studying condensation heat transfer inside a tube in a microgravity environment. The model assumes laminar flow in the condensate film and an annular flow pattern. The local heat transfer coefficient is then calculated by gravitational acceleration, gi from 0 to 9.8 m/*** model was tested indirectly by measuring condensation heat transfer inside a vertical tube in a normal gravity environment through experiments.

关键词： condensation microgravity annular flow

Dispersion equation of a double shell-fluid coupled system

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Chinese Journal of Acoustics 1996年第4期15卷 350-357页

作者： ZHAO Xiang XU Jianxue and JIANG Jun(Research Institute for Nonlinear Dynamics, Xi’an Jiantong University Xi’an 710049)

The dispersion behaviour of a double shell-fluid system, which consists of two thin concentric cylindrical elastic shells coupled by the entrained annular fluid, is a fundamental for investigation of its vibroacoustical characteristics. Based on Flugge's infinite shell equations,the sound wave equation for the fluid field and boundary conditions at the fluidstructure interfaces, the dispersion equationfor the system is deduced and a corresponding numerical example is given in the paper.

关键词： Double shell annular flow Coupled system Dispersion equation