脉动流发生装置诱导弹性管束振动的实验研究

为了实现对换热器内弹性管束振动的有效激发和控制,提出了一种新型脉动流发生装置,搭建了脉动流诱导弹性管束振动测试实验台,测试了换热器内各排弹性管束在不同工况下的振动响应。结果表明:在脉动流发生装置诱导下,弹性管束主要有两个振动频率,一个频率基本不受入口流速的影响,另一个频率随入口流速的增加而增加;提出的脉动流发生装置,一方面使弹性管束的振动强度明显增加,另一方面在一定程度上解决了各排弹性管束振动不均的问题。     

Mass transfer of solids in a pulsating liquid flow

A study is made of the kinetics of mass transfer in a solid-liquid system in a column with a pulsating flow and in a circulation loop.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 1, pp. 28–34, January, 1981.     

Modulation of nonlinear waves in a viscous fluid contained in a tapered elastic tube

In the present work, treating the arteries as a tapered, thin walled, long and circularly conical prestressed elastic tube and the blood as a Newtonian fluid, we have studied the amplitude modulation of nonlinear waves in such a fluid-filled elastic tube, by use of the reductive perturbation method. The governing evolution equation is obtained as the dissipative nonlinear Schrödinger equation with variable coefficients. It is shown that this type of equations admit solitary wave solutions with variable wave amplitude and speed. It is observed that, the wave speed increases with distance for tubes of descending radius while it decreases for tubes of ascending radius. The dissipative effects cause a decay in wave amplitude and wave speed.     

Stability of the flow of a rotating liquid film along the inside surface of a cylindrical tube

Under consideration is the problem of formation of Taylor vortices in a rotating film of a viscous incompressible fluid.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 6, pp. 1061–1065, June, 1980.     

Nonisothermal flow of a polymeric liquid under a pulsating pressure gradient

A study has been made of the effects of pressure-gradient pulsations on the nonisothermal flow of a nonlinear liquid with memory in an annular channel.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 3, pp. 361–368, September, 1986.     

Evolution equations for nonlinear waves in a tapered elastic tube filled with a viscous fluid

In this work, employing the reductive perturbation method and treating the arteries as a tapered, thin walled, long and circularly conical prestressed elastic tube, the propagation of weakly nonlinear waves is investigated in such a fluid-filled elastic tube. By considering the blood as an incompressible viscous fluid, depending on the viscosity and perturbation parameters we obtained various evolution equations as the extended Korteweg-de Vries (KdV), extended KdV Burgers and extended perturbed KdV equations. Progressive wave solutions to these evolution equations are obtained and it is observed that the wave speeds increase with the distance for negative tapering while they decrease for positive tapering.     

Oscillating two-phase flow in a prestressed thick elastic tube

Summary The pulsating flow of a fluid with dusty particles in a prestressed thick walled elastic tube has been studied. The tube, subjected to a static inner pressure P_i and an axial stretch λ, is taken to be an incompressible, isotropic, elastic material. The fluid with particles is treated as incompressible Newtonian. Employing the theory of small deformation superimposed on large initial deformations, for an axially symmetric perturbed motion the governing equations are obtained in cylindrical polar coordinates. The analytical solutions of the equations of motion for the dust and the fluid have been obtained. Because of the variable character of the coefficients of the resulting equations for the solid body they are solved numerically. The dispersion relation is obtained as a function of the stretch, the thickness ratio and the parameters for dusty particles.     

Mass transfer between solid particles and a pulsating liquid flow

Mass transfer in a solid-liquid system with a flow subjected to pulsations is investigated. Large acceleration of mass transfer is obtained. Criterial equations are derived, describing mass transfer under pulsating flow conditions.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 5, pp. 813–817, May, 1978.     

Enthalpy flow rate of a pulse tube in pulse tube refrigerator

An integration formula of enthalpy flow rate along a pulse tube in pulse tube refrigerators is described on the assumption of sinusoidal mass flow rate and sinusoidal pressure fluctuation. For ideal double inlet and ideal orifice pulse tube with helium as working medium, it is simplified to a polynomial formula. Polynomial formulas for roughly evaluating the volume of the pulse tube in ideal double inlet and ideal orifice pulse tube refrigerators are also given.     

Oscillating two-phase flow in an elastic tube

Summary Analytical expressions of dust and fluid velocities have been obtained for small amplitude waves having large wave length. Equations giving the wave-velocity and its damping factor have been derived. Corresponding graphs for various values of dust parameters and elasticity of the wall of the thin walled tube have been drawn. It is found that both the wave-velocity and its damping factor decrease with the increase in mass-concentration of dust and also they increase with the increase in Poisson's ratio of the wall of the tube.

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Schwingende Zweiphasenströmung in einem elastischen Rohr

Zusammenfassung Analytische Ausdrücke der Staub- und Flüssigkeitsgesch windigkeiten werden für kleine Amplituden von Wellen mit großer Wellenlänge erhalten. Gleichungen für die Geschwindigkeit der Welle und ihr Dämpfungsverhalten werden hergeleitet und zugehörige Diagramme für verschiedene Werte des Staubparameters und der Wandelastizität des dünnwandigen Rohres erhalten. Es wird gefunden, daß sowohl die Wellengeschwindigkeit als auch der Dämpfungsfaktor mit zumehmender Massenkonzentration des Staubs abnehmen und daß sie mit der Poissonzahl der Rohrwand zunehmen.

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With 3 Figures

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On leave from Bolpur College, Bolpur, West Bengal, India.     

Vibration of an elastic tube excited by a turbulent flow

Results are presented of measurements of the vibrations of an elastic tube that is excited by a turbulent flow therein. It is shown that the longitudinal component of tube vibration exceeds the transverse component by 8–18 dB in the medium frequency range f ~ 300–3000 Hz.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 3, pp. 367–369, September, 1988.     

Oscillatory liquid flow in elastic porous tubes

Summary An analytical method of solution of some problems of laminar, oscillatory flow in elastic porous tubes is given. The mathematical model is based on an one-dimensional approach to the liquid motion. The derived formulae describe the main flow characteristics: pressure, velocity, local and surface outflow of fluid. Influence of geometric dimensions, mechanical properties of elastic tubes, local outflow and filtration through the porous wall, on liquid motion durability is analysed. A simple method of experimental determination of functional parameters is shown.     

A model of liquid flow in a channel with elastic walls

It is suggested to describe a liquid flow in a cylindrical round channel with elastic walls in terms of a two-fluid model used to describe the flow of He II in narrow capillaries near absolute zero. The idea is based on a similar (phonon-like) shape of the spectrum of elementary excitations at small wavenumbers k. The calculations show that the density ρ_n of a normal (i.e., viscous) liquid component (water in a steel tube) at 300 K is about 50 times smaller than the total density. This explains the paradox related to flow in a round tube for which anomalously large Reynolds numbers (Re∼10⁵) are observed. Since Re∼ρ_n, real Reynolds numbers must also be about 50 times as small, that is, on the same order of magnitude as those for a flow between planes under otherwise equal conditions. A physical reason for the appearance of superfluidity at high (∼300 K) temperatures is a decrease in repulsion between small density fluctuations in the liquid, which is related to their interaction being screened by elastic waves in the channel walls.     

Elastoviscous liquid flow development in a tube under constant pressure head

The nonisothermal transient process of flow of a nonlinearly elastoviscous liquid in a circular tube is numerically studied for the case of pulsed application of a pressure head.     

Capacitance-based liquid holdup measurement of cryogenic two-phase flow in a nearly-horizontal tube

Liquid holdup measurement of cryogenic fluids is an area of considerable significance because of its inevitable occurrence in LNG transportation, rocket propellant delivery and superconducting equipment cooling, etc. To measure the liquid holdup of cryogenic two-phase flow, a capacitance sensor was carefully designed, which consists of a pair of optimized concave-electrode form with the electric circuit for the small capacitance detection. Four flow patterns were realized to evaluate the performance of the sensor in visualization experiments with liquid nitrogen and vaporous nitrogen. An image method was employed to calibrate the capacitance sensor, which led to a mathematical relationship between the capacitance and the liquid holdup. The results indicated that the obtained correlation between liquid holdup and capacitance satisfactorily coincided with the measured data.