In order to study the pressure characteristics of slug flow in horizontal curved tubes,two kinds of curved tubes with central angle 45° and 90° respectively are studied,of which are with 0. 5m circumference ...In order to study the pressure characteristics of slug flow in horizontal curved tubes,two kinds of curved tubes with central angle 45° and 90° respectively are studied,of which are with 0. 5m circumference and 26 mm inner diameter are used. When the superficial liquid velocity or the superficial gas velocity is constant,the pressure fluctuations and the probability distribution of the average velocity of slug flow are clear for all of the five experimental conditions. The results of experiment show that the pressure characteristics of slug flow in curved tubes have periodic fluctuations. With the rise of central angle,the period of pressure fluctuation is more obvious. The system pressure of the slug flow increases with the increasing of superficial liquid/gas velocity. Meanwhile,the probability distribution of pressure signal shows regularity,such as unimodal,bimodal or multimodal.展开更多
In this paper, A method, consisted of perturbation method, Garlerkin method and finite-difference method, is designed to calculate fully developed flows in curved tubes of rectangular cross-section. It costs less comp...In this paper, A method, consisted of perturbation method, Garlerkin method and finite-difference method, is designed to calculate fully developed flows in curved tubes of rectangular cross-section. It costs less computation than that of direct solving N-S equations, and prevents from building high-order difference equations and extra dealing with the boundary conditions. Numerical results in the situation of small curvature and low Dean number is in accordance with former's numerical and experimental results in quality, and it shows the feasibility of this paper's method.展开更多
The chaotic transients of a curved fluid conveying tube subjected to a nonlinear foundation are investigated. The assumption of the inextensibility of the tube is applied to derive the nonlinear differential equation ...The chaotic transients of a curved fluid conveying tube subjected to a nonlinear foundation are investigated. The assumption of the inextensibility of the tube is applied to derive the nonlinear differential equation of motion via the Newtonian approach, with the differential quadrature method used to discretize the curved tube model in the spatial domain. And the nonlinear dynamic motion equation is obtained. The numerical analysis shows that, the final steady states are sensitive to the initial system conditions in a large parameter region of the fluid speed. This phenomenon of chaotic transients is infrequent for fluid conveying tubes.展开更多
The number and distribution of the singular points of streamlines in the cross-section of steady flow through a curved tube ate discussed by using the method of topological structure analysis. And a theoretical criter...The number and distribution of the singular points of streamlines in the cross-section of steady flow through a curved tube ate discussed by using the method of topological structure analysis. And a theoretical criterion is obtained for the bifurcation of flow vortexes for the secondary flow turning from two-vortex structure into four-vortex structure. Furthermore, the critical Dean number for bifurcation and the semi-analytical expressions of stream function and axial velocity are given by using Galerkin technique. The result of calculation is consistent with the theoretical criterion.展开更多
A linear complex equation for slender ring shells overall bending in a meridian plane is given based on E. L. Axelrad's theory of flexible shells. And the non homogeneous solution is obtained from W. Z. Chien...A linear complex equation for slender ring shells overall bending in a meridian plane is given based on E. L. Axelrad's theory of flexible shells. And the non homogeneous solution is obtained from W. Z. Chien's solution for axial symmetrical slender ring shells to investigate the overall bending problem of Ω shaped bellows subjected to pure bending moments. The values calculated in the present paper are very close to the existing experiment. Thus Chien's work on axial symmetrical problems for ring shells has been extended to overall bending problems.展开更多
基金Supported by the National Natural Science Foundation of China(No.5130416)
文摘In order to study the pressure characteristics of slug flow in horizontal curved tubes,two kinds of curved tubes with central angle 45° and 90° respectively are studied,of which are with 0. 5m circumference and 26 mm inner diameter are used. When the superficial liquid velocity or the superficial gas velocity is constant,the pressure fluctuations and the probability distribution of the average velocity of slug flow are clear for all of the five experimental conditions. The results of experiment show that the pressure characteristics of slug flow in curved tubes have periodic fluctuations. With the rise of central angle,the period of pressure fluctuation is more obvious. The system pressure of the slug flow increases with the increasing of superficial liquid/gas velocity. Meanwhile,the probability distribution of pressure signal shows regularity,such as unimodal,bimodal or multimodal.
文摘In this paper, A method, consisted of perturbation method, Garlerkin method and finite-difference method, is designed to calculate fully developed flows in curved tubes of rectangular cross-section. It costs less computation than that of direct solving N-S equations, and prevents from building high-order difference equations and extra dealing with the boundary conditions. Numerical results in the situation of small curvature and low Dean number is in accordance with former's numerical and experimental results in quality, and it shows the feasibility of this paper's method.
基金Project supported by the National Natural Science Foundation of China (No. 10272051).
文摘The chaotic transients of a curved fluid conveying tube subjected to a nonlinear foundation are investigated. The assumption of the inextensibility of the tube is applied to derive the nonlinear differential equation of motion via the Newtonian approach, with the differential quadrature method used to discretize the curved tube model in the spatial domain. And the nonlinear dynamic motion equation is obtained. The numerical analysis shows that, the final steady states are sensitive to the initial system conditions in a large parameter region of the fluid speed. This phenomenon of chaotic transients is infrequent for fluid conveying tubes.
文摘The number and distribution of the singular points of streamlines in the cross-section of steady flow through a curved tube ate discussed by using the method of topological structure analysis. And a theoretical criterion is obtained for the bifurcation of flow vortexes for the secondary flow turning from two-vortex structure into four-vortex structure. Furthermore, the critical Dean number for bifurcation and the semi-analytical expressions of stream function and axial velocity are given by using Galerkin technique. The result of calculation is consistent with the theoretical criterion.
文摘A linear complex equation for slender ring shells overall bending in a meridian plane is given based on E. L. Axelrad's theory of flexible shells. And the non homogeneous solution is obtained from W. Z. Chien's solution for axial symmetrical slender ring shells to investigate the overall bending problem of Ω shaped bellows subjected to pure bending moments. The values calculated in the present paper are very close to the existing experiment. Thus Chien's work on axial symmetrical problems for ring shells has been extended to overall bending problems.
