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1.
The transient flow of liquid in the pipe with fluid machinery is analysed in this pa-per.The theoretic solution of the transient flow produced due to the regulation of fluid machin-ery is found by use of the method of the Laplace transformation.  相似文献   

2.
TRANSIENT PRESSURE BEHAVIOR FOR HORIZONTAL WELL IN DOUBLE-POROUS MEDIATRANSIENTPRESSUREBEHAVIORFORHORIZONTALWELLINDOUBLE-PORO...  相似文献   

3.
In this paper, the effects of polymer additives and nozzle shape on the proper-ties of high pressure water jet discharging into the air are investigated by theoryand experiments. Criteria of judging the jet quality are put forward. And, a methodthat can be used in analysing the fluid flow within the nozzle is developed. Then,the calculated results are compared with the experiments that we carried out;it is shown that the degree of agreement between the two is good. At last, themechanism to improve on the jet quality with polymer additives is discussed.  相似文献   

4.
This paper is aimed at a systematic discussion on the basic equations for two-phasetransient flow and the theory of pressure waves and interfacial waves.The characters of the ba-sic equations have been analyzed.The formulas for wave speed of pressure and interfacial waveshave been derived.It has been proved that various mathematical models can be unified by theproposed integrating model and various wave speed formulas can be unified by the derived uni-versal formula.The basic equations for the separated flow model are ill-conditioned because ofthe unreasonable neglect of the pressure differences between the phases and the interfaces.Driftflux model can improve the accuracy if some additional equations are provided.However theymust be carefully chosen.The basic equations for homogeneous flow model are well-conditionedand they can be used in two-phase transient flow,especially in the cases of no velocity slips be-tween the phases.  相似文献   

5.
This paper presents a higher order difference scheme for the computationof the incompressible viscous flows.The discretization of the two-dimensional incompress-ible viscous Navier-Stokes equations,in generalized curvilinear coordinates and tensor for-mulation,is based on a non-ataggered grid.The momentum equations are integrated intime using the four-stage explicit Runge-Kutta algorithm [1]and discretized in space us-ing the fourth-order accurate compact scheme[2]The pressure-Poisson equation is dis-cretized using the nine-point compact scheme.In order to satisfy the continuity constraintand ensure the smoothness of pressure field,an optimum procedure to derive a discretepressure equation is proposed [9][3]The method is applied to calculate the driven cavityflow on a stretched grid with the Reynolds numbers from 100 to 10000.The numerical re-sults are in very good agreement with the results obtained by Ghia et al [7]and includethe periodic solutions for high Reynolds numbers.  相似文献   

6.
Spherical symmetry convective-dispersive transport of a tracer or contaminant from continue and slug injection well in semi-infinite porous media is of significance,especially for the tracer test in huge thick formation.The partial equation describing the transport process belongs to confluent hypergeometric equation.With variable substitution and Laplace transform,the partial equation may be coverted Weber equation and it's solution is represented by parabolic cylinder function.We found the analytical solution by analytical inversion.Besides,we also obtained the early-time and late-time approximate solution.In the paper we compared these solutions and investigated the basic characteristics of concentration distribution and change.In early-time and late-time the approximate solution is of significance.  相似文献   

7.
The numerical solution of incompressible viscous flow over an aerofoil is obtainedby H-type grids and a special difference scheme. The method of mass flux corection is introducedwith success in order to accelerate convergence in iteration of velocity and pressure calculation.  相似文献   

8.
1. INTRODUCTION Turbulent boundary layer flows over surface irregularity are of significant importance from both fundamental and practical essences. Among others, turbulent flows over backward-facing step (hereinafter referred to BFS) received widespread …  相似文献   

9.
1 . INTRODUCTIONTheflowinhelicalpipesisverycomplexandveryimportantinboththechemicalindustryandthepetroleumindustry .AlotofworkhasbeendonebyMurataetal.[1] ,Wang[2 ] ,Germano[3 ,4 ] ,Kao[5] ,Tuttle[6] ,andLiu[7] .ButtheyonlystudiedtheNewtonianfluidinhelicalpipes .Thereisno…  相似文献   

10.
This is the erratum to the article [zhang Jin-hong, Yan Chang-qi, Gao Pu-zhen, Journal of Hydrodynamics, 2009, 21(5)]. The fig.5 is corrected.  相似文献   

11.
A fundamental solution for homogeneous reservoir in infinite space is derived by using the point source function with the consideration of the threshold pressure gradient. The fundamental solution of the continuous point source function is then derived based on the Green function. Various boundary conditions of the reservoirs are considered for this case and the corresponding solutions are obtained through the mirror image reflection and the principle of superimposition. The line source solution is obtained by integration. Subsequently, the horizontal-well bottom hole pressure response function for a non-linear gas flow in the homogeneous gas reservoir is obtained, and the response curve of the dimensionless bottom hole pressure and the derivative for a horizontal well in the homogeneous gas reservoir are obtained. In the end, the sensitivities of the relevant parameters are analyzed. The well test model presented in this paper can be used as the basis of the horizontal well test analysis for tight gas reservoirs.  相似文献   

12.
According to the assumption of slightly compressible fluid, the quadratic gradient term in the nonlinear partial differential equations for the traditional well-test model is usually neglected. The linear partial differential equation is thus established. It is known that neglecting the quadratic gradient term results in errors for long-time well tests. A nonlinear flow model for fractal medium is constructed and the quadratic gradient term is considered. The exact solutions of the fractal reservoir models are obtained by Laplace transform and Weber transform in a constant-rate and constant-pressure production for an infinitely large system. This paper addresses the variation of pressure with fluid compressibility coefficient and fractal reservoir parameters. The plots of the typical pressure curves are constructed, and the results can be applied to well-test analysis.  相似文献   

13.
The flow performances of water, white oil and Hydrolyzing Polyacrylamide (HPAM) solution in fused quartz channels and the effect of wettability on the microscale flow shave been studied respectively in this paper. The adaptability of classical fluid mechanics in channels with different sizes has been discussed. The results show that water flows in channels of 2μm diameter also have few size effects and white oil flow accord with classical fluid mechanics theory in channels of 25μm diameter too, but polymer solution appears an obvious size effect as diameters of channels decrease to 16μm. The wettability does not produce any influences on the water or white oil flows in channels of 25μm or 50μm diameter. The experimental technology of microscale flows has been first applied for studying the flow performances of pores in low permeability reservoir. This study found a base for deep investigating the percolation mechanism in low permeability reservoirs.  相似文献   

14.
指出了《水电站压力钢管设计规范(SD144—85)》介绍的地下埋管结构分析方法的不足.采用弹性理论多层厚壁圆筒接触问题模型,分别按“砼衬砌未开裂、钢管、砼衬砌层、围岩联合承载”,“砼衬砌已裂穿,仅传递径向压力”二类工况,建立了地下埋管应力计算方法,给出了砼衬砌开裂判别条件及地下高压管道应力,变位相对精确解计算表达式.  相似文献   

15.
This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design of the radial blade and CFD technique. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the forward-skewed blade has demonstrated the improvements in efficiency, total pressure ratio, Stable Operating Range (SOR) and less aerodynamic noise. Detailed flow measurement and computation were performed for outlet flow field for investigating the responsible flow mechanisms. The results show the forward-skewed blade can cause a spanwise redistribution of flow toward the blade mid-span and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at mid-span.  相似文献   

16.
Experimental Study on oil-water two-phase flow patterns and pressure loss was conducted on a horizontal steel pipe loop with 26. 1mm inner diameter and 30m total length. The working fluids are white oil, diesel oil and tap water. Several instruments, including a new type of liquidprobe are successfully integrated to identify 7 different flow patterns. The characteristics of the flow patterns and the transition process were observed and depicted in this paper.Investigation revealed that the pressure loss was mainly depended on the flow paiterns.  相似文献   

17.
With the governing equations for the flow of the power-law fluid in annulus with the inner cylinder executing a planetary motion being transformed by using the undetermined coefficient method, the formula of pressure gradient for this flow under the given flow rate and the relevant numerical calculation method are given in this article. Through the experiments on the flow of Hydrolyzed Polyacrylamide (HPAM) aqueous solution which can be regarded as a power-law fluid, the calculated results of the pressure gradient values are compared with measured data, the mean relative error between them is smaller than 5%, which verifies the results presented in this article.  相似文献   

18.
Gas-liquid two-phase flow occurs increasingly in some dynamic devices operating in the oceanic condition. The relative data are limited with respect to flow characteristics, so the present study is to investigate systematically single-phase pressure drop, and to develop the theory for frictional factor under the rolling condition. Using deionized water as the test fluid, a series of experiments of single–phase flow were conducted in pipe with the inner diameter of 34.5 mm. The test section was horizontally settled on the rolling apparatus, and its regularity was similar to simple harmonic motion. It is found that the pressure drop during rolling motion fluctuate with the change of the rolling period and rolling angle, which is significantly different from fluid motion in a steady state. By the contrast between experiment results and stable-state theory values, existing correlations can not predict present frictional factor very well. Therefore, in the present article, the single-phase frictional factor is correlated with the Reynolds number for rolling motion, and its computated results agree well with experimental data.  相似文献   

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