PHOENICS User 2004s International Conference, Australia, May, 2004 1 FLUID FIELD ANALYSIS OF HIGH PRESSURE THROTTLE VALVEAND ITS STRUCTURE IMPROVEMENT.

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PHOENICS User 2004’s International Conference, Australia, May, 2004

FLUID FIELD ANALYSIS OF HIGH PRESSURE THROTTLE VALVEAND IT’S STRUCTURE IMPROVEMENT

Presentation: Dr. Lian Zhanghua

Southwest Petroleum Institute

Chengdu, Sichuan Province

P.R. of China

P.O. Box 610500

Email: [email protected]

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Introduction

Theoretical analysis of throttle valves

Geometry model of the cone valve

CFD analysis of a wedge valve

Discussions of structure improvement

Conclusions

Contents

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Introduction

Fig.1 Valve rod fatigue fracture Fig.2 Valve body washout

Fig.1 shows the valve rod fracture accident that occurred at Dongqiu well No.8 in Tarim Oil Field in May of 2002. 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.

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Theoretical analysis of throttle valves

1. The flow coefficient

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40 45 50

Fl ow rate coeffi ci ent C

open

ing(

%)

Val ve openi ngVal ve cl osi ng

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40 45 50


open

ing(

%)

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40 45 50


open

ing(

%)

Val ve openi ngVal ve cl osi ng

Fig.3 Relation between flow coefficient and opening of the cone valve

C Q P

22

2

vP

2. The flow resistance coefficient

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Geometry model of the cone valve

D

D

d

θ

x

Fig.4 The structure section CAD model of the cone valve

Fig.5 Geometry structure section 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.

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1. Computation and solution

Fig.6 Pressure contours Fig.7 Velocity vectors

Analysis of the CFD results of the cone valve

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Analysis of the CFD results of the cone valve

2. Results analysis

Fig.8 Streamline pattern

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1. Geometry

Valve rod Valve rod Valve rod

a. one slope surface b. an arc surface c. two slope surface Fig.9 Schematic diagram of structure of wedge valve Fig.10 Structure CAD

model of wedge valve

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2. Result analysis

0

5

10

15

20

25

30

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

r od st r oke( mm)

pres

sure

dro

p(MP

a)

Fig.11 Relation of pressure vs. stroke

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3. Analysis of flow field pattern


Fig.12 Velocity vector patterns Fig.13 Velocity contour

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Stroke of the valve core

(mm)

flowing area(mm2)

wetted perimeter

(mm)

equivalent diameter

(mm)

pressure drop(MPa)

flow resistance coefficient

3 92.86 60.26 6.16 26.438 1592.43

4 134.19 68.01 7.89 24.674 1486.18

5 176.61 74.39 9.50 22.789 1372.64

6 219.28 79.85 10.98 20.278 1221.40

7 261.64 84.55 12.38 17.462 1051.78

8 303.35 88.68 13.68 14.347 864.16

9 344.15 92.37 14.90 11.011 663.22

10 383.89 95.68 16.05 8.300 499.93

11 422.44 98.64 17.13 5.058 304.66

12 459.74 101.35 18.14 4.096 246.71

13 495.74 103.81 19.10 3.249 195.70

14 530.44 106.07 20.00 2.919 175.82

15 563.84 108.14 20.86 2.829 170.40

Table 1 Pressure drop, flow resistance coefficient of the wedge valve at different opening


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Discussions of structure improvement

In order to get a better distribution of the fluid field, the paper pr

esented a wedge surface that consists of two slopes, shown as in F

ig.9c. From the figure, we could see that the valve core of the wedg

e valve consists of two slopes, and the bottom slope is parallel to th

e 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 op

timum, the production has been applied in the oil field, its life is 5~7

times that of the cone valve.

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Conclusions

1. The 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.

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Conclusions

4. 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.

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Thanks

PHOENICS User 2004s International Conference, Australia, May, 2004 1 FLUID FIELD ANALYSIS OF HIGH PRESSURE THROTTLE VALVEAND ITS STRUCTURE IMPROVEMENT.

Documents

valve core

cone valve slide

valve parts

valve cavity

cone valve cfd analysis

phoenics user

valve body washout

s international conference