Cfd simulation on different geometries of venturimeter

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 07 | Jul-2014, Available @ http://www.ijret.org 456
CFD SIMULATION ON DIFFERENT GEOMETRIES OF
VENTURIMETER
P. Hari Vijay1
, V. Subrahmanyam2
1
M.Tech Scholar, Department of Mechanical Engineering, Kakinada Institute of Technology and Science, Divili,
Andhra Pradesh, India
2
Associate Professor, Department of Mechanical Engineering, Kakinada Institute of Technology and Science, Divili,
Andhra Pradesh, India
Abstract
This paper describe an analytical approach for comparison of four different models to describe the velocity, pressure, turbulence
and mass flow rate taken place in the venturimeter and graph are plotted. Venturimeter are most commonly used for flow meters
for measuring volumetric or mass flow rate and velocity of fluid flowing through the venturimeter. Hence are also know as
variable head meters. Variable head meters work on the principle that a variation of the flow rate through a constriction with a
constant cross-sectional area causes a pressure drop suffered by the fluid as it flows through the constriction. The pressure drop
is related to the flow rate, and hence variations of the pressure drop can be used to measure variations in the flow rate. Fluent
soft ware was used to plot the characteristics of the flow of fluid through the flow meter and gambit software was used to design
the 2D model. Two phase computational fluid dynamic calculation, using K-Epsilon model were employed. The numerical results
were validated against experimental data from the literature and were found to be in good agreement. The pressure recovery is
better in the venturi meter.
Keywords: Gambit, Fluent, K-Epsilon model..
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1. INTRODUCTION
In different applications like chemical, paper and minerals
processing industries these flow meters are used and also in
order to control these processes and to calculate mass
balances for these processes it is important to be able to
accurately measure the flow rate of these fluids as they
move through pipes, conduits, or channels. Variable head
meters work on the principle that a variation of the flow rate
through a constriction with a constant cross-sectional area
causes a pressure drop suffered by the fluid as it flows
through the constriction. The pressure drop is related to the
flow rate, and hence variations of the pressure drop can be
used to measure variations in the flow rate.
Fig-1.1: Venturimeter
A sketch of a typical venturimeter is shown in Fig 1.1.
The behavior of the fluid as it passes through the venturi is
understood by writing the Bernoulli equation using the
conditions at the entrance and the throat, and at the throat
and the exit. As the fluid passes from the entrance to the
throat, its velocity increases and its pressure decrease. Upon
passing from the throat to the exit, the velocity of the fluid
decreases and its pressure increases, largely recovering to its
value at the entrance. The venturimeter is designed to
recover most of the pressure drop.
2. PROCEDURE AND GEOMETRY
The current study used FLUENT software, to solve the
balance equation using control volume approach. These
equations are solved by converting the complex partial
differential equations into simple algebraic equations. The
simple geometry is done in the GAMBIT software, a fine
meshing is done by using successive ratio and later given
the boundary conditions for the geometry and for the media.
This file imported into Fluent software and has given the
input values like velocity, mass flow rate, pressure,
temperature etc.,
The geometry was done in the GAMBIT with
measurements; pipe diameter is 30mm, radius of the pipe
15mm and length of the pipe 200mm. Defining required
boundaries like inlet, outlet and wall of the geometry and
mesh under tetrahedron. Defining the boundary conditions
for the water. The velocity at inlet is 4m/sec and the
gravitational acceleration of 9.81 m/s2 in downward flow
direction was used.

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Fig-2.1: First model venturimeter.
Fig-2.2: Second model venturimeter.
Fig-2.3: Third model venturimeter.
Fig-2.4: Forth model venturimeter.
3. SOLUTION STRATEGY
The simulation is done in the FLUENT based upon the
governing equations. The steps followed in the fluent are
define Model, define Material, define cell zone, boundary
condition, solve, iterate, and analyze results. The convergent
of the solution is shown in below fig 3.1.
Fig-3.1: Iterations of solution.
3.1. Continuity Equation.
Continuity Equation also called conservation of mass. The
overall mass balance is
Input – output = accumulation
Assuming that there is no storage the Mass input = mass
output.
However, as long as the flow is steady (time-invariant),
within this tube, since, mass cannot be created or destroyed
then the above equation will be
m1
.
= m1
.
(1)
dm1
dt
=
dm1
dt
(2)
ρA1u1 = ρA2u2 (3)
A1v1 = A2v2 (4)
3.2. Momentum Equation and Bernoulli Equation.
It is also called equation of motion .According to Newton’s
2nd law (the time rate of change of momentum of the fluid
particles within this stream tube slice must equal to the
forces acting on it).
F = mass* acceleration

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Consider a small element of the flowing fluid as shown
below, Let
dA : cross-sectional area of the fluid element,
dL : Length of the fluid element,
dW : Weight of the fluid element,
u : Velocity of the fluid element,
P : Pressure of the fluid element.
Assuming that the fluid is steady, non-viscous (the frictional
losses are zero) and incompressible (the density of fluid is
constant).
The forces on the cylindrical fluid element are,
Pressure force acting on the direction of flow (PdA).
Pressure force acting on the opposite direction of flow
[(P+dP)dA].
A component of gravity force acting on the opposite
direction of flow (dW sin θ).
Hence, Total force = gravity force + pressure force
The pressure force in the direction of low
Fp = PdA – (P+dP) dA = – dPdA (5)
The gravity force in the direction of flow
Fg = – dW sin θ {W=m g = ρ dA dL g}.
= – ρ g dA dL sin θ {sin θ = dz / dL}.
= – ρ g dA dz. (6)
The net force in the direction of flow
F = m a {m = ρ dA dL .
= ρ dA dL a.
= ρ dA u du. (7)
We have
ρ dA u du = – dP dA – ρ g dA dz {÷ ρ dA }
dP/ ρ + udu + dz g = 0 --------- Euler’s equation of motion.
Bernoulli’s equation could be obtain by integration the
Euler’s equation.
∫dP/ ρ + ∫udu + ∫dz g = constant.
P/ ρ + u2/2 + z g = constant.
ΔP/ ρ + Δu2/2 + Δz g = 0 -- Bernoulli’s equation.
4. RESULTS.
4.1. Results of First Model.
Fig-4.1.1: Pressure contours.
Fig-4.1.2: Velocity contours.
Fig-4.1.3: Turbulence contours.

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Chart-4.1.1: Static Pressure-Position.
Chart-4.1.2: Velocity-Position.
Chart-4.1.3: Turbulent-Position.
Table-4.1.1: Results of flow analysis.
s.no parameters Min. Max.
1 Pressure(Pascal) -53977.21 5552.164
2 Velocity(m/s) 0 9.4006
3 Turbulent(m2
/s2
) 0.2347 5.28177
Table-4.1.2: Results of mass flow rate.
Mass Flow Rate (kg/s)
Interior -48874.855
Inlet 239.56801
Outlet -239.56801
Wall 0
4.2. Results of Second Model.

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1 Pressure(Pascal) -90194.45 13095.87
3 Turbulent(m2/s2) 0.2672125 11.630932
Interior 1027.7252
Inlet 239.56801
Outlet -239.56801
Wall 0
4.3. Results of Third Model.

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1 Pressure(Pascal) -51152.82 5681.665
3 Turbulent(m2/s2) 0.1972782 4.908975
Interior -58327.486
Inlet 239.56801
Outlet -239.56801
Wall 0
4.4. Results of Forth Model.

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1 Pressure(Pascal) -19414.05 7617.83
3 Turbulent(m2/s2) 0.1887413 2.143962
Interior -48615.779
Inlet 239.56801
Outlet -239.56801
Wall 0
5. CONCLUSIONS
The flow through venturi meter was numerically simulated
with water by steady flow in k-epsilon scheme. The major
observations made related to the pressure, turbulence,
velocity contours and mass flow rate in the process of flow.
The accuracy of results is with in 5%. The velocity and
pressure distribusions are discribed brifly and graphs are
plotted.
To conclude, this examination results indicate that FLUENT
can be used with high degree of accuracy to visualize the
various contours of velocity, pressure and turbulence can be
understand clearly, the relationship between the mass flow
rate and pressure drop for each flow meter is done and
pressure recovery is better in the venturimeter.
REFERENCES
[1]. Anderson, J. D. (1995). Computational fluid dynamics:
The basics with applications (6th Ed.). New York, NY:
Mcgraw Hill, Inc.
[2]. Versteeg, H.K. & Malalasekera, W. (2007). An
Introduction to Computational fluid dynamics: The Finite
Volume Method (2nd Ed), New Jersey: Pearson education
ltd
[3]. Cengel, Y. A. & Cimbala J. M. (2010). Fluid
Mechanics: Fundamentals and applications (2nd Ed), Noida,
UP, India: Tata McGraw-Hill Education.
[4]. Sapra, M.K., Bajaj, M., Kundu, S.N., Sharma, B.S.V.G.
(2011). Experimental and CFD investigation of 100 mm size
cone flow elements.Flow Measurement and Instrumentation,
22, 469–474.
[5]. Singh, R.K., Singh, S.N., Seshadri, V. (2009). Study on
the effect of vertex angle and upstream swirl on the
performance characteristics of cone flowmeter using CFD.
Flow Measurement and Instrumentation, 20, 69–74.
[6]. Hojat Ghassemi, Hamidreza Farshi Fasih (2011).
Application of small size cavitating venturi as flow
controller and flow meter. Flow Measurement and
Instrumentation, 22, 406–412.
[7]. Denghui He, Bofeng Bai (2012). Numerical
investigation of wet gas flow in Venturi meter. Flow
Measurement and Instrumentation, 28, 1–6.
[8]. Singh, Rajesh Kumar, Singh, S.N., Seshadri V. (2010).
CFD prediction of the effects of the upstream elbow fittings
on the performance of cone flowmeters. Flow Measurement
and Instrumentation, 21, 88–97.
[9]. Reader-Harris, M.J., Brunton, W.C., Gibson, J.J.,
Hodges, D., Nicholson, I.G. (2001). Discharge coefficients
of Venturi tubes with standard and non-standard convergent
angles. Flow Measurement and Instrumentation, 12, 135–
145.
[10]. Hall, G.W. Application of Boundary Layer Theory to
Explain some Nozzle and Venturi Peculiarities Trans. IME,
London Vol. 173 No.36 1959.

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BIOGRAPHIES:
P.Hari Vijay completed schooling from
Geetanjali public school, East Godavari
district with 68% marks. Completed B.Tech
degree from Aarupadai veedu institute of
technology with 60%. Now pursuing
M.Tech from Kakinada Institute of
Technology and Science, Tirupathi(V),
Divili, East Godavari Dist., A.P., India.
Mr. V.Subrahmanyam working as Assoc.
Professor and Head of Mechanical
Engineering Department in KITS-Divili
Engineering college, Andhra Pradesh, India.
He has 15 years of teaching experience in
various reputed engineering colleges. He
guided so many B.Tech and M.Tech projects. He has three
publications in reputed international journals. He is doing
research in Nano-Technology and Thermal Engineering

Cfd simulation on different geometries of venturimeter

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Cfd simulation on different geometries of venturimeter