Presentation on theme: "Presentation: Dr. Lian Zhanghua"— Presentation transcript:
1Presentation: Dr. Lian Zhanghua FLUID FIELD ANALYSIS OF HIGH PRESSURE THROTTLE VALVEAND IT’S STRUCTURE IMPROVEMENTPresentation: Dr. Lian ZhanghuaSouthwest Petroleum InstituteChengdu, Sichuan ProvinceP.R. of ChinaP.O. Box
2Contents Introduction Theoretical analysis of throttle valves Geometry model of the cone valveCFD analysis of a wedge valveDiscussions of structure improvementConclusions
3IntroductionFig.1 shows the valve rod fracture accident that occurred at Dongqiu well No.8 in Tarim Oil Field in May of Fig.2 shows the valve body and the double flange spools washout in the kill-job at Wushen well No.1 in Tarim Oil Field. The early pressure-control techniques and the throttle system could no longer meet the demand in production, gathering and transporting.Fig.1 Valve rod fatigue fractureFig.2 Valve body washout
4Fig.3 Relation between flow coefficient and opening of the cone valve Theoretical analysis of throttle valves1. The flow coefficient2. The flow resistance coefficientFig.3 Relation between flow coefficient and opening of the cone valve
5Geometry model of the cone valve the CAD model of every valve was built with Pro/E software, and the geometry data have been saved as STL format files, and then imported into PHOENICS software for the CFD modeling.Fig.4 The structure section CAD model of the cone valveFig.5 Geometry structure section of the cone valve
6Analysis of the CFD results of the cone valve 1. Computation and solutionFig.6 Pressure contoursFig.7 Velocity vectors
7Analysis of the CFD results of the cone valve 2. Results analysisFig.8 Streamline pattern
8CFD analysis of a wedge valve 1. Geometrya. one slope surface b. an arc surface c. two slope surfaceFig.9 Schematic diagram of structure of wedge valveFig.10 Structure CAD model of wedge valve
9CFD analysis of a wedge valve 2. Result analysisFig.11 Relation of pressure vs. stroke
10CFD analysis of a wedge valve 3. Analysis of flow field patternFig.12 Velocity vector patternsFig.13 Velocity contour
11Stroke of the valve core flow resistance coefficient CFD analysis of a wedge valveTable 1 Pressure drop, flow resistance coefficient of the wedge valve at different openingStroke of the valve core(mm)flowing area(mm2)wetted perimeterequivalent diameterpressure drop(MPa)flow resistance coefficient 392.8660.266.1626.4384134.1968.017.8924.6745176.6174.399.5022.7896219.2879.8510.9820.2787261.6484.5512.3817.4628303.3588.6813.6814.347864.169344.1592.3714.9011.011663.2210383.8995.6816.058.300499.9311422.4498.6417.135.058304.6612459.74101.3518.144.096246.7113495.74103.8119.103.249195.7014530.44106.0720.002.919175.8215563.84108.1420.862.829170.40
12Discussions of structure improvement In order to get a better distribution of the fluid field, the paper presented a wedge surface that consists of two slopes, shown as in Fig.9c. From the figure, we could see that the valve core of the wedge valve consists of two slopes, and the bottom slope is parallel to the central axial line, and parallel to the surface of the shell body. It is to avoid the direct impact of the fluid on the wall. Through plentiful fluid field analysis, this structure (shown as Fig.9c) has been the optimum, the production has been applied in the oil field, its life is 5~7 times that of the cone valve.
13ConclusionsThe flow resistance is greater when the fluid flows into the region that abruptly changes its shape than the region that gradually changes its shape. In the design and installation of the throttle valve, the flow passage, that abruptly changed, should be used. With enough flow passage area, the bigger flow resistance is better.2. The erosion to the valve parts such as valve cavity, valve core, mainly comes from the mud impacting on the valve parts at a high velocity as the mud medium directly rushes to the shell body. The tangent direction of the end section of the valve core should be parallel with the central axial line of the shell body, namely a plane, at the end section of the valve core, parallel with the central axial line of the shell body.3. The cone valve is equivalent to a cantilever beam; this type of valve easily produces vibration and fatigue damage. The wedge valve is better in the fluid field and the structure. For the high pressure throttle valve, the wedge valve is recommended.
14Conclusions4. The shell body of the bottom valve cavity washout occurred in the use of the slope wedge valve.5. Changing to an arc surface wedge valve, the erosion damage reduces, but the linear adjusting is poor.6. After changing the wedge surface of the valve core to two slopes, the lack of the plane wedge valve and the arc surface wedge valve is make up better.7. For the wedge valve that consists of two slopes, converse angle or circular arc should be adopted at the interface of the two slopes in order to reduce erosion to the slope that parallel with the central axial line of the shell body.