本文選題：CFD + 氣液兩相流��； 參考：《長江大學》2015年碩士論文

【摘要】：在油氣生產領域,油、氣、水通常是從油井同時產出,并以氣液兩相的形式進行長距離輸送。在管道氣液兩相的流動過程中,當輸送管道系統(tǒng)內為多相流動時,流體的速度和壓力不斷變化,產生不穩(wěn)定流動和變形(或運動),這種不穩(wěn)定流動對管道變形的變形產生很大影響會導致管道系統(tǒng)的損壞。因此,針對管道系統(tǒng)的熱-流-固耦合特性進行的深入研究具有廣泛的工程背景和現實意義。本文從數值模擬角度對油氣管道兩相流流型、管道-地層溫度場、流場與管道壁之間的熱-流-固耦合情況進行了數值預測研究。本文首先采用VOF多相流模型和標準k-e模型湍流模型對水平管道、鉛直管道和夾角60°的傾斜管道內常見的幾種流型進行了數值計算和分析。模擬結果表明：建立的二維模型可再現Baker流型圖關于水平管道中常見的7種流型,即彌散泡狀流、泡狀流、活塞流、段塞流、環(huán)狀流、層流和波浪流,模擬結果與三維模型比較發(fā)現兩種模型下流型模擬結果差異性較��；數值模擬結果同時再現了Taitel流型圖關于鉛直管和傾斜管中常見的5種流型,即彌散泡狀流、泡狀流、段塞流和環(huán)狀流,流型預測達到預期效果,并對傾斜管中氣、液相流量的變化對傾斜管道內流型的影響進行了研究。此外,將112組不同角度下的流型模擬結果與Taitel流型圖進行對比,得到以下結論：在管道流型的數值模擬中,如若不考慮氣體的可壓縮性,在氣相折算速度特別大的情況下管道內只會出現環(huán)狀流一種流型,如需進行氣相折算速度較大時的流型模擬,需要對模型進行修正；氣液兩相流在自下而上傾斜角度較大或者近似鉛直的管道中經常會呈現段塞流,對這種管道進行段塞流的特定研究具有十分重要的意義；管道傾角的變化會對管內可能出現的流型產生了較為明顯的影響；在傾斜管道的數值模擬中頻繁出現了霧狀流這種流型,這種流型在Taitel流型圖中是沒有的,而在傾斜管道對霧狀流研究中卻不可忽略。論文進而對某集輸管道進行了模擬研究,整個管路由三段水平管路(L1,L3,L5),兩段傾斜管路(L2,L4)和一段垂直管路組成,管長9.1 m,內徑0.06m,壁厚0.007m。在本研究中,首先采用FLUENT軟件對管道埋地部分進行溫度場數值預測,對管道的最優(yōu)埋地深度進行優(yōu)化并解算得出管道埋地敷設情況下冬夏兩季的管道壁面溫度。研究結果表明,在不同季節(jié)溫度條件下管道周圍土壤溫度場分布差異很大,有保溫層情況將比不帶保溫層的受影響范圍減少50%-90%,該段管道的最優(yōu)埋地深度是1.2m(存在凍土層),冬夏兩季的管道外壁面溫度的模擬結果分別為12℃和31℃。在管道-地層溫度場數值模擬結果的基礎上采用ANSYS Workbench模塊進行管道的熱-流-固耦合分析。采用FLUENT軟件解算得到氣液兩相在集輸管道內不同時刻的兩相分布、界面變化和沿程壓降,并結合集輸管道各拐角及特定截面處的氣相體積分數云圖和速度曲線圖對管內流型進行了特定分析。結果表明：不同管段分別出現了分層流、波浪流、氣泡流、段塞流和環(huán)狀流等多種流型,氣液兩相流在流經水平段進入傾斜向上管路或者垂直向上管路時,在拐角處最容易產生積液；在管道90°彎管處容易出現較大漩渦。將流體對管道內壁面的壓力載荷、管道體上的溫度載荷加載到管道上,同時對管道進行固定約束,解算得到管道固體壁面的最大位移量、等效應力和等效應變。結果表明：管道的管材、壁面溫度和管內流量的變化都會對長輸管道的變形位置、變形大小和等效應力、應變產生影響,溫度載荷和氣液量變化產生的影響較為明顯。
[Abstract]:In the field of oil and gas production, oil, gas and water are usually produced at the same time from the oil well and are transported in a long distance in the form of gas-liquid two phases. In the process of gas and liquid two-phase flow in the pipeline, when the pipeline system is multiphase flow, the velocity and pressure of the fluid are constantly changing, resulting in unstable flow and deformation (or motion), such unstable flow, The deformation of the pipeline has a great influence on the damage of the pipeline system. Therefore, the deep research on the thermal fluid solid coupling characteristics of the pipeline system has extensive engineering background and practical significance. The heat of the two phase flow, the temperature field of the pipeline formation and the heat between the flow field and the wall of the pipeline from the numerical simulation point of view. The numerical prediction study of the fluid solid coupling situation is carried out. Firstly, the VOF multiphase flow model and the standard k-e model turbulence model are used to calculate and analyze several common flow patterns in the horizontal pipe, the plumbing pipe and the inclined pipe with the angle of 60 degrees. The simulation results show that the established two-dimensional model can be reproduced by the Baker flow pattern about water. 7 common flow patterns in flat pipes, namely, dispersion bubble flow, bubble flow, piston flow, slug flow, annular flow, laminar flow and wave flow, are compared with the three-dimensional model. The results of the two models are less different, and the results of numerical simulation reproduce the 5 common flow patterns of the Taitel flow pattern on the plumbing and the inclined tube. Diffusion bubble flow, bubbly flow, slug flow and annular flow, flow pattern prediction reached the expected effect, and the influence of the change of gas and liquid flow in the inclined pipe on the internal flow pattern of the inclined pipe was studied. In addition, the flow pattern simulation results under 112 groups of different angles were compared with the Taitel flow pattern, and the following conclusions were obtained: the number of flow patterns in the pipeline In the value simulation, if the compressibility of gas is not considered, there is only a circular flow pattern in the pipe in the case of high gas phase conversion speed. If the flow pattern is simulated with high gas phase conversion speed, it is necessary to modify the model. The gas and liquid two phase flow is in a large or nearly straight pipeline. The slug flow is often presented, which is of great significance to the specific study of the slug flow in this kind of pipeline. The change in the dip angle of the pipe will have a more obvious effect on the possible flow pattern in the tube; the flow pattern of the foggy flow appears frequently in the numerical simulation of the inclined pipe, and this flow pattern is not in the Taitel flow pattern. It is not negligible in the study of the foggy flow in the inclined pipeline. The paper then simulated the pipeline of a certain gathering pipeline. The whole pipe route is composed of three segments (L1, L3, L5), two segments (L2, L4) and a vertical line, the length of the pipe is 9.1 m, the inner diameter 0.06m, and the wall thickness 0.007m. in this study, the pipeline is first buried by the FLUENT software. The ground part carries out the numerical prediction of the temperature field, optimizes the optimal buried depth of the pipeline and calculates the wall temperature of the pipeline in the two quarter of winter and summer in the pipeline buried. The results show that the distribution of soil temperature field around the pipeline is very different under different seasonal temperature conditions, and the condition of the insulation layer will be more than that without the insulation layer. The optimum burying range is 50%-90%, and the optimal buried depth of the pipeline is 1.2m (frozen soil layer). The simulation results of the outer wall temperature of the pipeline in the two quarter of winter and summer are 12 and 31, respectively. On the basis of the numerical simulation results of the pipe formation temperature field, the ANSYS Workbench module is used to analyze the heat flow solid coupling analysis of the pipes. The FLUENT software solution is used. The two phase distribution of gas and liquid two phases in the gathering pipeline, the interface change and the pressure drop along the path are calculated, and the internal flow pattern of the pipe is analyzed with the gas phase volume fraction and velocity curves at the corner of the gathering pipeline and the specific cross section. The results show that the stratified flow, wave flow and bubble flow appear in the different pipe segments, respectively. In a variety of flow patterns, such as slug flow and annular flow, when the gas and liquid two phase flow enters the inclined upward pipe or vertical upward pipeline through the horizontal section, it is the most easy to produce the fluid at the corner, and the larger whirlpool is easy to appear at the 90 degree bend pipe of the pipeline. The maximum displacement, equivalent stress and equivalent strain of the pipe solid wall are obtained by the fixed constraint on the pipe. The results show that the pipe material, the wall temperature and the flow in the tube will affect the deformation position, the deformation size and the equivalent stress, the stress and the change of the temperature load and the gas and liquid quantity. The influence is more obvious.

【學位授予單位】：長江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE832

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本文編號：1851933