The use of relief valves is crucial for the safety of power plants. Indeed, these valves, simple but robust in their design, provide the ultimate protection when all other safety systems are inadequate. This study is focused on valve opening characteristics which can be studied through the determination of flowforces applied on the valve disk. A spring-loaded safety relief valve (SRV) (1½ in. G 3 in.) and its transparent model are tested under static conditions. The spring is removed and the forces, exerted at the valve disk for different inlet pressures and lift positions, are measured in compressible, incompressible, and two-phase flows. Results indicate that even for relatively small qualities (i.e., 5–10%), two-phase mixtures approach compressible flow behavior (especially for the higher lifts) in terms of disk force. Additionally, an inverse flowforce of air and water is noticed above a certain value of valve lift. Numerical simulations with a commercial computation fluid dynamics (CFD) code are performed in a 2D axisymmetric model of the valve for validation purposes. The main motivation of these computations is to obtain the qualitative physical explanation of this phenomenon revealing the displacement of the sonic line which occurs in air flow simulations. Finally, the importance of precise adjustment of the valve ring (in the smallest valve opening) for its optimal use is stressed by quantitative analysis using CFD simulations.

References

References
1.
PED
,
1997
, “
Pressure Equipment Directive-PED. 97/23/EC
,”
European Commission—Enterprise and Industry
.
2.
ISO 4126-1
,
2004
,
Safety Devices for Protection Against Excessive Pressure
,
International Organization for Standardization
.
3.
ISO 4126-10
,
2010
,
Safety Devices for Protection Against Excessive Pressure–Part 10: Sizing of Safety Valves for Gas/Liquid Two-Phase Flow
,
International Organization for Standardization
.
4.
API RP 520
,
2000
,
Sizing, Selection and Installation of Pressure-Relieving Devices in Refineries, Part 1-Sizing and Selection
,
7th ed.
,
American Petroleum Institute Recommended Practice 520
,
Washington, DC
.
5.
Leung
,
J. C.
,
1996
, “
Easily Size Relief Devices and Piping for Two-Phase Flow
,”
Chem. Eng. Prog.
,
92
(
12
),
pp.
28
50
.
6.
Diener
,
R.
, and
Schmidt
,
J.
,
2004
, “
Sizing of Throttling Device for Gas/Liquid Two-Phase Flow, Part 1: Safety Valves
,”
Process Saf. Prog.
,
23
(
4
),
pp.
335
344
.10.1002/prs.10034
7.
Diener
,
R.
, and
Schmidt
,
J.
,
2005
, “
Sizing of Throttling Device for Gas/Liquid Two-Phase Flow, Part 2: Control Valves, Orifices, and Nozzles
,”
Process Saf. Prog.
,
24
(
1
),
pp.
29
37
.10.1002/prs.10035
8.
Föllmer
,
B.
, and
Schnettler
,
A.
,
2003
, “
Challenges in Designing API Safety Relief Valves
,
Valve World
,
10
,
pp.
39
43
.
9.
Chabane
,
S.
,
Plumejault
,
S.
,
Pierrat
,
D.
,
Couzinet
,
A.
, and
Bayart
,
M.
,
2009
, “
Vibration and Chattering of Conventional Safety Relief Valve Under Built Up Back Pressure
,”
3rd IAHR International Meeting of the WorkGroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems
,
Oct.
14–16
,
Brno, Czech Republic
,
International Association of Hydro-Environment Engineering and Research
,
pp.
281
294
.
10.
Song
,
X. G.
,
Cui
,
L.
, and
Park
,
Y. C.
,
2010
, “
Three Dimensional CFD Analysis of a Spring-Loaded Pressure Relief Valve From Opening to Re-Closure
,”
ASME 2010 Pressure Vessels and Piping Conference
,
July
18–22
,
Bellevue Washington, USA
,
American Society of Mechanical Engineers, Paper No. PVP2010-25024
.
11.
Beune
,
A.
,
2009
, “
Analysis of High Pressure Safety Valve
,”
Ph.D. thesis
,
Eindhoven University of Technology
,
Eindhoven
.
12.
Vallet
,
C.
,
Ferrari
,
J.
,
Rit
,
J.-F.
, and
Dehoux
,
F.
,
2010
, “
Single-Phase CFD Inside a Water Safety Valve
,”
ASME 2010 Pressure Vessels and Piping Conference
,
July
18–22
,
Bellevue Washington
,
American Society of Mechanical Engineers, Paper No. PVP2010-25619
.
13.
Moncalvo
,
D.
,
Friedel
,
L.
,
Jörgensen
,
B.
, and
Höhne
,
T.
,
2009
, “
Sizing of Safety Valves Using Ansys CFX-Flo
,”
Chem. Eng. Technol.
,
32
(
2
),
pp.
247
251
.10.1002/ceat.200800530
14.
Tyco
,
2008
,
Pressure Relief Valve Engineering Handbook
,
Technical Publication No. TP-V300, Tyco Flow Control, NJ
.
15.
Kourakos
,
V.
,
Chabane
,
S.
,
Rambaud
,
P.
, and
Buchlin
,
J.-M.
,
2010
, “
Hydrodynamic Forces, Pressure and Mass Flux in Two-Phase Air-Water Flow Through Transparent Safety Valve Model
,”
ASME 2010 Pressure Vessels and Piping Conference
,
July
18–22
,
Bellevue Washington
,
American Society of Mechanical Engineers, Paper No. PVP2010-25440
.
16.
Corbin
,
F.
,
Pozzoli
,
R.
, and
François
,
P.
,
2009
,
Essais de soupapes-Banc eau. Documents Qualité CETIM T-8600-a, Centre Technique des Industries Mécaniques, Techniques des fluides et des écoulements
,
74 route de la Jonelière BP 82617, 44326 Nantes Cedex 3
.
You do not currently have access to this content.