Using CFD Method To Predict Wet Gas Measurement Model

Driven by oil and gas industry demands, wet gas non-separate onlinemeasurement technology has attracted a growing number of attention of gas producers,researchers and flowmeter manufacturers. This study is dedicted to wet gasnon-separate online measurement via computational fuid dynamics (CFD) and hascompleted the following works:(1) This article has studied the simulation methods of high pressure wet gasmeasurement and explored the possibilty of using Eulerian model. According to thehigh pressure conditions of standard Venturi, carring out turbulence model studyunder the Eulerian model condition, the conclusion that RSM turbulence model ismore applicable is achieved.Using the RSM turbulence model and Eulerianmultiphase model for simulation, the results were compared with the DPM model andNEL real flow experiment. the experimental data are compared. The maximum errorof Eulerian model is3.75%and the root mean square error is2.08%. The error issmall and is slightly better compared to the DPM model, thus we can obtained aconclusion that Eulerian model can be used for high pressure wet gas simulation.(2) Based on DN50-β=0.55,β=0.4and DN32-β=0.4three kinds of long throatVenturi tube, according to PetroChina Southwest Oil and gas field condition--3MPaand the range of gas flow rates are from10000Nm3/d to160000Nm3/d withGVF>91%, the Eulerian model and DPM model were used for calculation. Modelsfrom DN50-β=0.55and β=0.4simulation were used on the real life test respectivelyand then compared. For the gas phase measurement of DN50-β=0.55and β=0.4these two kinds of structure, the root mean square error of Eulerian model is about4%,DPM model is around5%, the root mean square error of modified Eulerian is lessthan DPM model. For the liquid phase measurement of DN50-β=0.4structure, DPMmodel is slightly better; for DN50-β=0.55structure, Euler-Yuan model is better.After comparing and weighing, we can draw a conclusion that Eulerian model is moreaccurate than DPM model under the wet gas condition.(3) According to the high pressure gas field with large quantity of liquid conditionin Tarim gas field, based on the DN50-β=0.55,β=0.4of the two kinds of structure ofthe long throat Venturi tube, the multiphase flow Eulerian model was used to established gas-liquid two phase predicted model. The mediums of DN50-β=0.55simulation are gas and condensent oil, while the mediums of DN50-β=0.4simulationare gas, ondensent oil and water. The fitting accuracy of gas phase predicted modelwith mass gas is high with errors between0.01%-0.4%, while in the small gascontented points are slightly worse, except the root mean square errors ofDN50-β=0.55structure under14MPa are about3%-4%, the others are around1%-2%.Liquid phase model of the root-mean-square full scale error is small and around1%.