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3129
www.ijifr.com Copyright © IJIFR 2015
Research Paper
International Journal of Informative & Futuristic Research ISSN (Online): 2347-1697
Volume 2 Issue 9 May 2015
Abstract
This paper presents testing of butterfly valve for change in across pressure. The experimentation is carried out at 90°, 60° and 40° of valve disc by change in pressure drop, at this conditions discharge is measured. The study focuses on finding out flow characteristics and flow coefficient of 100mm butterfly valve. For higher performance it’s more and more essential to know the flow characteristic around the valve. Experimentation is conducted to observe the flow patterns and to measure valve flow coefficient when butterfly valve with various opening degrees. Furthermore, the results of experiment are compared with ANSYS FLOTRAN results.
1. Introduction
A butterfly valve is a type of flow control device that controls the flow of gas or liquid in a variety
of process. It consists of a metal circular disc with its pivot axes at right angles to the direction of
flow in the pipe, which when rotated on a shaft, seals against seats in the valve body. This valve
offers a rotary stem movement of 90º or less in a compact design [1]. The importance of butterfly
valves has been more and more increasing in the pipe system. And there are so many studies on the
characteristics, i.e. the flow coefficient, the torque coefficient, the pressure recovery factor and so
on. With the development of the Computational Fluid Dynamics (CFD), the approach of using the
technique of computational fluid dynamics has been substantially appreciated in mainstream
scientific research and in industrial engineering communities. By now, the CFD simulation by
Testing And Performance Evaluation
Of Butterfly Valve Paper ID IJIFR/ V2/ E9/ 005 Page No. 3129-3139 Subject Area
Automobile
Engineering
Key Words Pressure Drop, Flow Characteristic, Flow Coefficient, ANSYS FLOTRAN
Sachin K. Pisal 1
Assistant Professor
Department of Automobile Engineering
Sanjeevan Engineering and Technology Institute Kolhapur- Maharashtra
Suresh M. Sawant 2
Professor
Department of Mechanical Engineering
Rajarambapu Institute of Technology
Islampur - Maharashtra
3130
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
commercial code has been proved its feasibility to predict the flow characteristic. There have been
also many studies on valve using computational Fluid dynamics analysis [3].
The flow coefficient allows determining what size valve is required for a given application.
Pressure drop is a key criterion in valve selection. Increased pressure drop across a valve means
higher costs for pressurizing the fluid system [5]. Higher pressure drops decrease a valve's life
expectancy, and may even damage the rest of the fluid system. High pressure drops across open
valves should be avoided. A measure of a valve's potential pressure drop is the Cv (flow coefficient)
factor [4].
In past years extensive research work has been carried out in the area of CFD analysis. The
main advantage is to develop a model by using the commercial code ANSYS FLOTRAN, which
accurately represents the flow behaviour and provide a two and three-dimensional numerical
simulation of water around the butterfly valve and estimate the pressure drop, flow coefficient and
hydrodynamic torque coefficient. It is the first step towards improving valve design. [2].
2. Testing and result analysis
2.1 Flow coefficient (Cv): A constant Cv related to the geometry of a valve, for a given travel, that
can be used to establish flow capacity. It is the number of U.S. gallons per minute of 60ºF water that
will flow through a valve with a one pound per square inch pressure drop.
√
(2.1)
Where
Q = design flow rate (lit/s)
G = Specific gravity relative to water
= Allowable pressure drop across wide open valve in kg/cm2
2.2 Design of pipe diameter
We know
Maximum discharge of pump Q = 14 lit/s
By using continuity equation
VQ (2.2)
Where A = Area of pipe in „m‟
V = velocity of water in „m/s‟
VdQ
2
4 (2.3)
Assume velocity = 1.7 m/s
7.14
14 2
d
d = 0.102 m
d = 100 mm or 4 inch diameter pipe has been selected
2.3 Principal test rig arrangement:
Experimental set up for testing butterfly valve comprises electric motor of 5 H.P. whose
maximum discharge is 14 lit/s, 1850cm head and 2880 rpm. Amount of water is getting lifted from
water storage tank by means of electric motor which is passing through pipe of 100 mm diameter
whose length is 4900 mm. The butterfly valve is mounted at distance of 20D at upstream and 10D at
downstream. The pressure gauge at upstream of butterfly valve is at distance of 2D from valve
centerline and 6D at downstream is shown in figure 1.1. Where „D‟ is diameter of butterfly valve
3131
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
disc. Butterfly valve disc is operated manually by using hand wheel. We can set position of disc at
required angle by this hand wheel.
To control pressure drop across butterfly valve water bypass valve is provided as shown in
figure 1.2. By using this bypass valve it is possible to regulate discharge through valve up to certain
extent.
Figure 1.1 Photograph of Mountings of pressure gauges in pipeline with respect to position of butterfly valve.
Figure 1.2 Photograph of water bypass valve arrangement for changing pressure across valve.
Figure 1.3 Photograph of Discharge measurement method
Water Bypass
Butterfly valve
Reducer
Venturimeter
Pressure gauge
3132
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
y = 8.4507e0.0041x R² = 0.7026
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
15 30 45 60 75 90
Axis Title
dicharge anf angle
Expon. (dicharge anfangle)
Dsi
cha
rge
in
lit
/s
Discharge through venturimeter is calculated by
√
√( ) ( ) (2.4)
Where
Q= Discharge in „lit/s‟
a1 = Area of venturimeter at convergent section in „cm2‟
a2 = Area of venturimeter at throat section in „cm2‟
H = Pressure head in „m‟
21 PP
H
(2.5)
= Density of water in „kg/cm3‟
= Coefficient of discharge
2.4 Experimental result analysis
While doing experimental analysis parameters like pressure at upstream and downstream of
valve, Discharge at different positions of valve disc, disc angle and bypass system have been taken
into consideration for measurement.
2.4.1 Operating condition of butterfly valve
2.4.1.1 Change in pressure drop across butterfly valve
Now pressure drop across butterfly valve is changed by operating bypass valve,
simultaneously disc angle is changed and discharge through pipe is measured by venturimeter.
Area of Venturimetera1 = 7850cm² and a2 = 961.625cm²
Table 1.1Change in pressure drop across the butterfly valve and disc angle
θ (°)
(kg/cm²)
(kg/cm²)
ΔP
(kg/cm²)
(kg/cm²)
(kg/cm²)
ΔP
(kg/cm²)
H (cm) Q
(lit/s)
90 1.6 1.2 0.4 1.65 1.55 0.10 9.8100E+04 13.3456 89
60 1.9 1.13 0.77 1.58 1.53 0.050 4.9050E+04 9.4954 45
40 2.1 0.9 1.2 1 0.95 0.05 4.9050E+04 9.4157 36
Fig.1.4 shows characteristic curves of butterfly valve by changing pressure drop and disc angle.
From fig. 1.6 a) clear that as degree of disc opens the rate of flow that is discharge through pipe goes
on increasing
(a)
Degree of disc opening
3133
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
y = 0.9864x - 2.3705 R² = 0.9731
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0 15 30 45 60 75 90
Axis Title
Cv curve
Cv curve
Linear (Cv curve)
Flo
w c
oe
ffic
ien
t
Degree of disc opening
y = -0.4812x + 6.1189 R² = 0.9492
0.3
0.8
1.3
1.8
2.3
2.8
5.0 7.0 9.0 11.0 13.0
DP and flow rate
Linear (DP and flow rate)P
ress
ure
dro
p k
g/
cm2
Discharge(Lit/s)
(b)
(c)
Figure 1.4 Characteristic curves of butterfly valve for change in pressure drop across the butterfly valve and disc
angle for 100 mm size. a) Degree of disc opening Vs Discharge b) Discharge Vs pressure drop across butterfly valve
c) Degree of disc opening Vs flow coefficient
When pressure drop across butterfly valve is high same time maximum discharge is obtained, it is
shown in fig. 1.6. When butterfly degree valve disc progress flow coefficient value increases.
2.5 The pressure and velocity distribution with varying disc angle and pressure in ANSYS
FLOTRAN
When valve disc is full open (at 90° valve disc angle) the discharge is maximum and value
of velocity is minimum due to more actual area of flow round the valve. As actual area of flow
decreases around the valve disc the value of velocity goes on increasing. The pressure and velocity
distribution with varying disc angle and pressure.
3134
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
Table 1.2 Simulation results of change in pressure drop across the butterfly valve and disc angle
Disc
angle(°)
Butterfly
valve pressure
P1 (kg/cm²)
Butterfly valve
pressure P2
(kg/cm²)
Butterfly valve
pressure drop (
P1-P2) (kg/cm²)
Velocity
in m/s
Discharge
in lit/s
Flow
Coefficient
( )
90 1.569 1.211 0.358 1.6 13.45 87
60 1.869 1.101 0.768 1.4 11.89 54
40 2.099 0.869 1.23 1.2 9.92 34
(a) (b)
(c) Figure1.5 a) Fluid velocity distribution b) Fluid velocity vector profile and c) Pressure distribution across 100mm
butterfly valve disc at 90°ofinlet velocity 1.7 m/s
(a) (b)
Low turbulence
3135
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
y = 0.0896x + 5.555 R² = 0.9752
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
15 25 35 45 55 65 75 85 95
Dis
cha
rge
in l
it/
s
Degree of disc Opening
(c)
Figure 1.6 a) Fluid velocity distribution b) Fluid velocity vector profile and c) Pressure distribution across 100mm
butterfly valve disc at 60° of inlet velocity 1.4 m/s
(a) (b)
(c)
Figure 1.7 a) Fluid velocity distribution b) Fluid velocity vector profile and c) Pressure distribution across 100mm
butterfly valve disc at 40° of inlet velocity 1.2m/s
(a)
High turbulence
3136
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
y = -0.1912x + 2.9314 R² = 0.9999
0.3
0.5
0.7
0.9
1.1
1.3
5 7 9 11 13
Pre
ssu
re d
rop
acr
oss
bu
tter
fly v
alv
e k
g/c
m2
Discharge in lit/s
y = 0.8804x + 14.231 R² = 0.9901
10
20
30
40
50
60
70
80
90
100
15 45 75
Flo
w c
oef
fici
ent
Degree of disc opening
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
0 15 30 45 60 75 90
Dis
cha
rge
in l
it/s
Degree of disc opening
Experimental
Simulation
Linear(Simulation)
Linear(Experimental)
(b)
(c)
Figure 1.8 Numerical characteristic curves of butterfly valve for change in pressure drop across the butterfly valve
and disc angle for100 mm size. a) Degree of disc opening Vs. Discharge b) Discharge Vs. pressure drop across
butterfly valve c) Degree of disc opening Vs. flow coefficient
(a)
3137
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
5.0 7.0 9.0 11.0 13.0
Pre
ssu
re d
rop
cro
ss b
utt
erfl
y v
alv
e
kg
/cm
2
Discharge in lit/s
Experimental
Simulation
Linear(Experimental)
Linear(Simulation)
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0 15 30 45 60 75 90
Flo
w c
oef
fici
ent
Degree of disc opening
Experimental
Simulation
Linear(Experimental)
Linear(Simulation)
(b)
(c)
Figure 1.9 Comparison between experimental and simulation method at 40°, 60° and 90°position of valve disc a)
Degree disc of opening and discharge b) Pressure drop across butterfly valve and discharge c) Degree of disc
opening and flow coefficient by changing pressure and valve disc angle.
When pressure drop is constant the pressure drop error is more at 40 degree of valve disc, it may due
to erroneous method of simulation. Flow coefficient error at 60 degree of valve disc is also more due
to same reason. The value of flow coefficient matches at 40 degree and 90 degree of valve disc
position.
3138
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
3. Conclusion
The investigation of the flow characteristics through a butterfly valve under different opening
angles and for incompressible flow is studied by experimental and computational fluid dynamics
techniques. The flow field is visualized and the performance factors of the valve are calculated and
compared against experimental data.
The simulation is done in computational fluid dynamic software ANSYS FLOTRAN in 40, 60
and 90 degree of butterfly valve disc with changing pressure drop and disc angle, with changing
pressure drop and disc angle. It is found that more turbulent flow is occurred when valve disc is at
40 and 60 degree, because of more obstacle area to water flow. When valve is full open at 90 degree
it is less. The loss coefficient directly depends on position of valve disc. As degree of valve disc and
discharge increases flow coefficient value goes on increasing. So the flow coefficient is function of
valve disc shape. Flow coefficient is independent of the inlet velocity but it is dependent on the
valve size.
4. Abbreviations and Acronyms
V Flow velocity
D Nominal diameter of pipe
Cv Flow coefficient
Pressure drop
Density or specific mass of fluid
Flow rate
ΔPmax Maximum pressure drop
G Specific gravity relative to water
L Length of pipe
A Area of pipe
d Diameter of throat of venturimeter
Area of venturimeter at convergent section
Area of venturimeter at throat section
H Pressure head
Coefficient of discharge
θ Butterfly valve disc angle
Butterfly valve upstream pressure
Butterfly valve downstream pressure
ΔP Upstream and downstream pressure drop at valve
Upstream pressure of venturimeter
Downstream pressure of venturimeter
ΔP Upstream and downstream pressure drop at venturimeter
References
[1] Jun-Oh Kim, Seol-Min Yang, Seok-Heum Baek and Sangmo Kang, “structural Design Strategy of
Double-Eccentric Butterfly Valve using Topology Optimization Techniques” World Academy of
Science, Engineering and Technology 66, (2012)..
[2] Xue Guan Song, Lin Wang, Seok HeumBaek and Young Chul Park. “multidisciplinary optimization
of a butterfly valve”. ISA Transaction 48, pp 370-377, (2009).
3139
ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)
Volume - 2, Issue - 9, May 2015 21st Edition, Page No: 3129-3139
Sachin K. Pisal ,Suresh M. Sawant :: Testing And Performance Evaluation Of Butterfly Valve
[3] C.K. Kim, J.Y. Yoon and M.S. Shin. “experimental study for flow characteristics and performance
evaluation of butterfly valves”, IOP Conf. Series: Earth and Environmental Science, pp. 1-7, (2010).
[4] Xue Guan Song and Young Chul Park.” numerical analysis of butterfly valve prediction of flow
coefficient and hydrodynamic torque coefficient”, Proceedings of the World Congress on
Engineering and Computer Science (2007).
[5] C.K. Kim, J.Y. Yoon and M.S. Shin. “experimental study for flow characteristics and performance
evaluation of butterfly valves”, IOP Conf. Series: Earth and Environmental Science, pp. 1-7, (2010).
Biographies
Sachin Pisal. Born on 21 May 1985 in Karad, India. Obtained Bachelor‟s degree
in Automobile Engineering and M.E. CAD/CAM/CAE from R.I.T. Sakharale,
Sangli, India. At present he is working as Asst. Professor in Automobile
engineering department at Sanjeevan engineering and Technology Institute
(S.E.T.I.) Panhala, Kolhapur India. His research interests include Fluid
Mechanics, Heat and mass transfer and computational fluid mechanics.. He is the
member and Faculty advisor of Society of Automotive Engineers (SAE).
Suresh Sawant obtained B.E. (Prod.) and M. E. (Mechanical) Shivaji University,
Kolhapur. Ph. D. (Mech.), National Institute of Technology, Warangal [A.P.]. He
is Professor at Rajarambapu Institute of Technology, Rajaramnagar, (Islampur).
He is Dean - Faculty of Engineering and Technology, Shivaji University,
Kolhapur. Member - Senate, Shivaji University, Kolhapur. Member - Academic
Council, Shivaji University, Kolhapur. Chairman - BOS (Automobile
Engineering), Shivaji University, Kolhapur.