| In oil and gas production fields, oil, water and natural gas are generally produced simultaneously and sent in form of gas-liquid two phases for long distance transportation. In the flowing process of gas-liquid, when there are multiple flowing phases in transmission pipeline system, the velocity and pressure of fluid constantly varies, which might generate unstable flowing and transformation(or movement), this kind of unstable flowing has great influence on pipeline’s transformation and would result in damage to pipeline system. Therefore, in-depth research on the pipeline system’s thermal-fluid-solid coupling characteristic has broad engineering background and practical significance. So this paper is related to the study of the two phase flow pattern, the temperature field and the thermal-fluid-solid coupling of pipe.This paper use the VOF multiphase flow model and standard k-e turbulence model to get the numerical calculation and analysis for the characteristic of flow in horizontal pipe, vertical pipe and pipe with 60° inclined angle, preliminary draw Angle 60 ° inclined pipe flow pattern figure, and compare with the data in related literature. The results show that:the Baker flow pattern figure about 7 kind of common flow patterns in horizontal pipeline can be reproduced in the two-dimensional model established, which is dispersed bubble flow, slug flow, bubble flow, slug flow, annular flow, laminar flow and wave flow, there is a small difference in the comparison of simulation results and 3D model, the Taitel flow pattern figure about 5 kind of flow patterns in the straight pipe and tilt pipeline can be presented in numeric simulation results, namely the dispersed bubble flow, bubble flow, slug flow and annular flow, the flow pattern prediction agrees to the desired effect, and the effect on the change of gas, liquid phase flow inclined tube in inclined pipeline the flow pattern is studied. In addition, about 112 groups of experimental data were calculated and plotted the flow pattern map. By comparing with Taitel flow pattern map, the conclusions are as follows:In the numerical simulation of pipeline’s flow pattern, if we set aside the compressibility of gas, only one annular flow pattern in the pipe under the condition of gas phase conversion velocity is particularly high, if need to conduct flow pattern simulation under this circumstances, which might need to modify the model; Gas-liquid two phase flow in pipe that the bottom-up inclined Angle is pretty large often presents slug flow, specific research on slug flow of the pipeline has great significance; Angle changes of pipe has more obvious influence on the possible flow pattern; This kind of misty flow type frequently appeared in the numerical simulation of inclined pipe, which can’t be seen in Taitel flow pattern figure, and can’t be ignored in misty flow of inclined pipes research.This paper made a further research by simulation of pipeline. The whole line consists three horizontal lines (L1, L3, L5) two inclined pipe(L2,L4) and a vertical pipe,9.1 meters length, inner pipe meter of 0.08m, wall thickness of 0.007 m. In this research, first use FLUENT software to predict the field temperature data of the buried pipeline section, establish the pipe-formation temperature field model, select optimal buried depth, calculate the temperature of wall in winter and summer pipeline. The results show that the temperature under the condition of soil temperature field around the pipe distribution difference is great in different seasons. The affected range decreased by 50%-90%. The pipeline’s optimal buried depth is 1.2 m. The temperature outside the pipe wall are 12℃ and 31 ℃ respectively in winter and summer.Finally, based on the prediction of the temperature field, we get the flow pattern of gas-liquid two-phase flow and the pressure load of the fluid solid boundary by using the software FLUENT, then we use ANSYS Workbench Static Structural to analyze the fluid solid coupling. We will set the fluid solid boundary and the pressure load on the inner wall of the pipeline, and the fixed constraint will be set on the entrance and wall to get the results of the displacement, stress and strain of the pipe wall. We got the distribution of the gas-liquid two-phase and the interface changes on the section of the pipe. The Resulted shows that different pipe section respectively appeared stratified flow, wave flow, bubble flow, slug flow and annular flow etc, when the gas-liquid two phase flow through horizontal section into the tilted upward or vertical pipe line, it was at the corner most likely to produce effusion; At the 90 "pipe’s bend was easy to appear larger vortex. Upload by the pressure load caused by flow to inner wall of pipeline and temperature of pipe body to pipe line, then fix and constraint the pipe, calculated the maximal displacement, equivalent stress and equivalent strain of pipe’s solid wall. Which turned out that material of pipes, wall temperature and flow volume changes all have impact on location, deformation size, equivalent stress and strain for long distance transportation, the impact on temperature load and gas-liquid volume changes are more obvious. |
PDF Full Text Request