ansys 15 2d fluid flow of fluid open channel and different solutions of removal of turbulence

1. TURBULENCE STUDY OF 2D -
MAGNETOHYDRODYNAMIC FLOW OVER
SQUARE RIB IN A OPEN CHANNEL
Master of Technology
in
Mechanical Engineering
By
SUJAY KUMAR PATAR
HALDIA INSTITUTE OF TECHNOLOGY ,HALDIA
pin-721657 w.b (india)
2018(may)

2. TOPIC COVERED
• Intro to cfd and ansys
• Objective anfd outcome
• Philosophy
• Mhd
• Problem ststement and boundary condition
• Project work decisions and steps
• Govornig equations
• Literature review
• Cfd solution methodology
• Results
• Future work
• conclution

3. computational Fluid Dynamics (CFD) and Computational Fluid Dynamics (CFD) and Multiphase
Fluid Flow Modelling .
ANSYS 15.0
some corporate fact
 The company name ansys was founded 2000
 Ansys 1 .0 was released 2000

4. OBJECTIVE
To analyze the effect of flow structure
 when a square rib is immersed in an Plain Open Channel Flow.
 MHD effect of different intensities on turbulence parameter
 when different strength of magnetic field is induced in flow over
square bluff body.
flow over open chanel with 2 square rib study the effect of mhd though
without experiment we get the required magnetic field for specific flow

5. COMPUTATIONAL FLUID DYNAMICS DYNAMICS (CFD) IS THE (CFD) IS THE SCIENCE,, SCIENCE OF
PREDICTING:
FLUID FLOW FLUID FLOW HEAT AND MASS TRANSFER HEAT AND MASS TRANSFER
CHEMICAL REACTIONS REACTIONS AND RELATED PHENOMENA BY SOLVING NUMERICALLY
THE AND RELATED PHENOMENA BY SOLVING NUMERICALLY THE SET OF SET OF GOVERNING
GOVERNING MATHEMATICAL EQUATIONS. EQUATIONS. CONSERVATION OF MASS, MOMENTUM,
ENERGY, SPECIES, ETC.
THE RESULTS OF CFD ANALYSES ARE RELEVANT IN:
CONCEPTUAL STUDIES OF STUDIES OF NEW NEW DESIGNS DESIGNS
DETAILED DETAILED PRODUCT PRODUCT DEVELOPMENT DEVELOPMENT
TROUBLESHOOTING TROUBLESHOOTING REDESIGN REDESIGN
CFD CFD ANALYSIS ANALYSIS COMPLEMENTS COMPLEMENTS TESTING AND TESTING
AND EXPERIMENTATION REDUCES ,REDUCES THE TOTAL THE TOTAL EFFORT EFFORT
REQUIRED REQUIRED IN THE IN THE EXPERIMENT EXPERIMENT DESIGN AND DATA
DESIGN AND DATA ACQUISITION

6. MAGNETOHYDRODYNAMICS
• Magneto hydrodynamics (MHD) has importance in both engineering and biological
:
• Some applications are :
• MHD generators,
• MHD flowmeters,
• plasma studies,
• cooling system of a nuclear reactor,
• geothermal energy extraction,
• blood flow problems.

7. • LORENTZ FORCE & ITS APPLICATION

8. PROBLEM STATEMENT
0.4 m.
0.2 m.
18 m.
Free Surface Level
8 m.
5 cm Square bar
Velocity Inlet Press
ure
Outl
et
Primary Phase - Air
Secondary Phase - Water
Smooth Bed – wall condition
Upper surface – symmetry condition
1 m.
Open channel flow is a flow in a channel (conduit) that is not completely filled
and a free surface is formed between the flowing fluid (water) and the air & The
gravity force is the main force that drives such flows

9. BOUNDARY CONDITION
• Inlet boundary conditions for turbulent quantities
• PRESSURE BASED SOLVER ,RE =60000 velocity 0.3 m/s
• At inlet boundary conditions additional quantities
have to be specified in turbulent flows depending on
the turbulence model selected. Typically there are
three options:
• 1) k-ε
• 2) Turbulence Intensity and Turbulence
Length Scale
• 3) Turbulence Intensity and Turbulent
Viscosity

10. PROJECT WORK DECISIONS
Problem Specification
1. Pre-Analysis
2. Geometry
3. Mesh
4. Model Setup
5. Numerical Solution
6. Numerical Results
7. Verification & Validation

11. MESHING AND EDGE SELECTION

12. • GOVERNING EQUATIONS
Continuity
0
x
u
i
i



jj
i
2
ij
i
j
i
xx
u
ν
x
p
x
u
u
t
u











   '
j
'
i
jjj
i
2
i
ij
j
i
uu
xxx
u
ν
x
p1
uu
xt
u















    kMbk
jk
t
j
i
i
SYρεGG
x
k
σ
μ
μ
x
ρku
x
ρk
t


























      ε
2
2εb3εk1ε
j
t
j
i
i
S
k
ε
ρCGCG
k
ε
C
x
ε
σ
μ
μ
x
ρεu
x
ρε
t



























Navier-
Stokes
equation
RANS
equation
Turbulence
Model K - ε

13. MHD EQUATIONS
where B is magnetic field in tesla,
E is electrical field in V/m, J is electric
current density vector (amp/m2)
Again, induced electric field and induced magnetic field where  is electric permittivity of
free space and  is magnetic pe
MHD approximation of Amperes Law yields :
rmeability in vacuum.
t
E
c
1
μBX 2


 j
  








2μ
B
B.B
μ
1
BX
2
j
Momentum equation with body force terms:
  ρgBXpV.Vρ
t
V
ρ 


j

B
H 

14. LITERATURE
REVIEW
Authors Year Work Done Important Finding
Hannes
Alfvén
1942 Research on Astronomy Termed MHD
Morley et
al.
2000 Compiled MHD work, done so far, related
to fusion technology
Work on enhancement of heat
transfer in liquid metal, liquid
Lithium , Flibe (Li2BeF4).
Gao et al. 2002 Numerical Schemes to solve the time
dependent governing equations of 2D
model VOF methodology
They showed that the field
gradient restrains and
destabilizes the flow.
Smolentse
v et al.
2002 They tuned ‘‘K–’’ model coefficients, using
computer optimization of available
experimental data for the friction factor &
MHD effects for different orientations of
the magnetic field in molten salt.
Turbulence reduction due to
the Joule dissipation resulting
in heat transfer degradation.
Especially near the free surface
because of turbulence
redistribution.
Smolentse
v et al.
2004 Study of wavy, turbulent flows of molten
salts in a spanwise magnetic field , using
modified K–ε model coupled to N-S
equations written in the thin-shear-layer
approximation.
Summarized the results of
experimental and theoretical
studies related to flow of poor
conductive (electrical and
thermal) liquids.

15. Authors Year Work Done Important Finding
Schuster et
al.
2008 Their MHD model was a combination of
the NS PDE and Magnetic Induction
derived from Maxwell equations.
A nonlinear Lyapunov-based boundary
feedback control law for mixing
enhancement in a Hartmann flow.
Takeuchi et
al.
2008 Experimental results on turbulent pipe
flow of an aqueous potassium hydroxide
solution under magnetic field using PIV
was compared with a DNS data base
They observed modification of the mean
flow velocity as well as turbulence
reduction with variable Ha No.
Xu et al. 2008 Boundary control law that stabilizes the
Hartman profile for low magnetic
Reynolds numbers in an infinite MHD
channel flow.
Their law achieved stability in the L2
of the linearized MHD equations,
ensuring local stability for the fully
nonlinear system.
Braun et al. 2009 Reviewed the overall feasibility of
electromagnetic flow control (EMFC)
concepts
EMFC with high voltage ionization
sources and experimental work -
propulsion, control, and power
generation systems
Pulugundl
a et al.
2013 Experimental methodology for the
measurement of Lorentz forces on a
small permanent magnet exposed to
liquid metal flow in a rectangular duct.
They achieved an accurate force
measurements in the range of micro-
newtons.
LITERATURE
REVIEW

16. CFD SOLUTION METHODOLOGY
 Commercial CFD Code of ANSYS FLUENT 15.0 used
 Volume of Fluid (VOF) Model
 Volume Fraction Equation
 The Momentum Equation
 The Implicit Scheme
 Standard k- model with ‘Standard Wall Function’for near wall treatment
 SIMPLE Pressure Velocity Coupling Solution method
 Second Order Upwind was chosen for spacial discretization of momentum, turbulent kinetic energy and turbulent dissipation rate.
     









n
p
qppqqqqqq
q
mmS
t q
1
.
1




       Fgp
t
T




 ..
    VmmSUV
t
n
1p
qppq
f
1n
f,q
1n
f
1n
q
n
q
n
q
1n
q
1n
q
q 















17. RESULTS

18. RESULTS FLOW OVER RIB AND
STREAMLINES EFFECT OF MHD
H=0 H=5
H=10 H=20

19. TKE TURBULANCE INTENSITY
WITH OUT MHD TKE K
-E MODEL

20. RESULTS (WITHOUT MHD)
Turbulance velocity vector
whole levels middle portion
Turbulance velocity vector colour by pressur whole levels
middle

21. OUTPUT XVELOCITY
OUTPUT VELOCITY
MAGNITUDE
RESULTS (WITHOUT MHD)

22. RESULTS OF GRAPHER 8 SOFTWARE
PLOT

23. TKE AFTER APPLYING MHD
H=0
H=5
H=10
H=15

24. VORTICITY
H=0
H=10
H=5
H=20

25. FUTURE WORK
Compiled MHD work development done so far, related to fusion
technology
Improvement of Reviewed the overall feasibility of electromagnetic flow
control (EMFC) concepts
Improvement of Experimental methodology for the measurement of
Lorentz forces on a small permanent magnet exposed to liquid metal flow
in a rectangular duct.
Improvement of Reviewed the overall feasibility of molten metal flow
control.

26. CONCLUTION
• Effect of single rib obstruction for the upstream positions is not visible for too much
distance.
• Here we need experimental data (experimental setup) to validate the software results.

27. THANK YOU