Interface Logic for KIVA3V

1
Interface Logic for KIVA-3V
GASTURBNLAB

• Ke Su and Chenn Q. Zhou
• Department of Engineering
• Purdue University Calumet

2
Outline

• Simulation of combustion flows
• Grid structure
• Numerical scheme
• Code basics relating to boundary conditions
• Data storage structure

3
V4 P4 T4 M4
Secondary Channel
Fuel Nozzle
V3 P3 T3 M3
Gas Flow to Turbine
Diffuser
Air Flow from Compressor
Liner
Secondary Channel
A Typical Combustor
4
Two Approaches for Combustor Simulation

• Single domain
• All components in combustor, including diffuser,
  secondary channels, and liner
• Separate domains
• Diffuser and secondary channel domain
• No chemical reactions, no particle phase
• Combustion domain, i.e., combustor liner

5
Single Domain Simulation

• Advantage
• More accurate boundaries
• Real time transient simulation
• No interface needed in computation
• Disadvantage
• More requirements for memory and speed due to
  more grids
• Coupling of secondary and combustion flows
• Unnecessary equations for diffuser and secondary
  flow domain

6
Single Computational Domain
Inlet boundary
Outlet boundary
Solid wall
Inlet
Outlet
Solid wall
7
Separate Domain Simulation

• Advantage
• Lower requirements for computer
• Exact equations for each domain
• No technical challenges
• Disadvantage
• Lower accuracy due to more boundary assumptions
• Interface between domains
• Lower accuracy for transient simulation

8
Diffuer and Secondary Flow Domain
Inlet boundary
Outlet boundary
Solid wall
Outlet
Inlet
Solid wall
9
Combustion Flow Domain
Inlet boundary
Outlet boundary
Solid wall
Inlet
Outlet
Solid wall
10
A Grid of Combustion Flow
A sector of 30 deg span of the combustor
11
Grid for Combustion Flow
Solid wall
Inlet boundary
Outlet boundary
Solid wall
Periodic boundary
Periodic boundary
12
Field Variables

• Vector (velocity)
• stored at nodes

6
7
5
8
2
3
1
4

• Scalars (pressure, temperature, species, etc.)
• stored at cell center
• constant over the cell

13
Node Odering

• Six neighbor indices of I4 establish complete
  connectivity

K
6
7
TOP I8TAB(I4)
J
5
8
I
DERRIERE I3TAB(I4)
2
3
1
4
LEFT IMTAB(I4)
RIGHT I1TAB(I4)
(I4)
FRONT JMTAB(I4)
BOTTOM KMTAB(I4)
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Global Grid Numbering

• For zone n IIII (j-1)NI(n)
  (k-1)NI(n)NJ(n)
• Global IJKIII ? NI(n-1)NJ(n-1)NK(
  n-1)

I1,NI(n)
K1,NK(n)
J1,NJ(n)
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Numerical Scheme

• Liquid phase (Phase A)
• Lagrangian calculation
• Gas phase (Phase B and C)
• Arbitrary Lagrangian-Eulerian method
• Phase B Lagrangian calculation
• Phase C Eulerian calculation
• Ability of moving coordinates for IC engine
• Interaction of liquid phase and gas phase

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Liquid Phase (Phase A)

• Lagrangian method
• Tracking single particles in computational domain
• Solving contributions of particles to mass,
  momentum and energy equations
• Governing equations
• Momentum equation
• Energy equation

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Gas Phase (Phase B and C)

• Arbitrary Lagrangian-Eulerian method
• Phase B
• Freezing convection, solving diffusion with
  computational cells moving with fluid.
• Phase C
• Freezing diffusion, solving convective transport
  associated with moving computational mesh, and
  rezoning flow field to new mesh
• Governing equations
• Continuity equation
• Momentum equations
• Energy equation
• Turbulence equations
• Species equations

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Marching Forward in Time

• Separate procedures for each step forward in time
• Lagrangian calculation of liquid phase (Phase A)
• Lagrangian calculation of flow field (Phase B)
• Mesh moves with the material (not for gas
  turbine application) no convection is across
  cell boundary.
• Convection calculation of flow field (Phase C)
• Flow field is rezoned onto the new mesh,
  convection is solved.
• Time step determination
• Time step must satisfy the Courant condition
  ?tlt ?x/Ur

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Types of Boundary Conditions

• Inlet boundary
• Outlet boundary
• Solid wall boundary
• Periodic boundary
• Boundary conditions for particle phase

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Inlet Boundary

• Variables given values
• Vector (velocity)
• Scalars (pressure, temperature, species, etc.)
• Variables for turbulence
• Turbulent kinetic energy
• Dissipation

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Inlet Boundary
Inlet Velocity at Nodes
Inlet Scalars at Centers of Cells
qin
qin
qin
qin
qin
qin
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Outlet Boundary

• Variable given value
• Pressure
• Variables with zero derivatives
• Velocity
• Scalars (pressure, temperature, species,
  turbulent kinetic energy and dissipation)

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Outlet Boundary
Outlet Pressure
Velocity and Scalars at Outlet
Outlet of Domain 1
qout
qout
qout
qout
qout
qout
Pressure from Domain 2
qout
qout
qout
qout
qout
qout
Domain 1
kNK(n)
kNK(n)-1
kNK(n)
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Inlet/Outlet Boundary Ordering

• Cell Numbering

Node Numbering
?y
I1TAB(10)
I1TAB(20)
I1TAB(5)
I1TAB(15)
I1TAB(I3TAB(20))
5
10
15
20
15
20
5
10
I3TAB(20)
4
14
19
9
9
14
19
4
I3TAB(19)
3
8
13
18
8
13
18
3
x
I3TAB(18)
7
12
17
2
7
12
17
2
I3TAB(17)
1
6
11
16
?x
11
16
1
6
I3TAB(16)
y
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Inlet/Outlet Interface

• If node numbers of both domain at interface are
  not consistent, interpolations are needed.

Inlet Boundary Domain 2
5
Outlet Boundary Domain 1
10
3
15
20
4
6
Inflow to Domain 2
9
14
3
19
8
2
13
Outflow from Domain 1
5
18
2
7
12
1
17
1
6
4
x
11
16
y
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Inlet/Outlet Interface

• Cell Numbering at Interface

Inlet Boundary Domain 2
5
10
5
Outlet Boundary Domain 1
10
15
20
15
4
20
9
4
Inflow to Domain 2
9
14
3
19
14
3
19
8
8
13
18
13
2
Outflow from Domain 1
18
2
7
12
7
12
17
1
17
6
1
11
6
x
11
16
16
y
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Solid Wall

• Velocity boundary
• Slip boundary (Gas velocity is set equal to the
  wall velocity)
• Non-slip boundary (Normal gas velocity is set
  equal to the normal wall velocity)
• Temperature boundary
• Adiabatic boundary (Wall heat flux is set to
  equal to zero)
• Fixed temperature boundary (Wall heat flux is the
  function of flow properties)

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Boundary Conditions for Liquid Phase

• Liquid phase is solved using Lagrangian method,
  therefore, boundary conditions for liquid
  droplets are also the initial conditions.
• Vector (velocity)
• Scalars (droplet temperature, size, etc.)

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Initial Conditions

• Liquid phase
• Initial conditions for liquid droplets are also
  the boundary conditions.
• Gas phase
• Initial values of variables velocity,
  temperature, pressure, turbulence, and species,
  etc.
• Ignition
• Ignition energy and ignitor locations.

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KIVA-3V Flowchart
START
Setup Initial and Boundary Conditions
New step
Solution of Liquid Phase
Solution of Gas Phase
No
Check Step Setting
Yes
End
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Input and Output

• Reading input data file
• Generating grids
• Specifying boundary nodes
• Outputting grid boundary file

Mesh Generation K3PREP
IPREP
ITAPE17

• Reading grid boundary file
• Reading operating condition file
• Solution time-marching
• Outputting result file

Main Program KIVA3
ITAPE5
ITAPE9

• Reading result file
• Display graphic results

Post Processor TECPLOT
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Data Storage Structure

• All variables (vector and scalars) transferred
  through common blocks and included in subroutines
• Preprocessor
• Comprep.i
• Main Program
• Comkiva.i Comfuel.i
• Data stored as follows
• q(ijk),
• where ijk iii ? NI(n)NJ(n)NK(n)
• iii i (j-1)NI(n-1)
  (k-1)NI(n-1)NJ(n-1)
• i 1, NI(n) j 1, NJ(n) k1,NK(n)
• n is the zone number

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Example

• Grid file OTAPE17
• i41,iverts
• i4,x(i4),y(i4),z(i4),fv(i4),idface(i4)
• i1tab(i4),i3tab(i4),i4,i8tab(i4),f(i4),bcl(i4),bcf
  (i4),bcb(i4),idreg(i4)
• Output file OTAPE9
• (f(n),fv(n),x(n),y(n),z(n),u(n),v(n),w(n),p(n),ro
  (n),vol(n),temp(n),amu(n),
• tke(n),eps(n),sie(n),n1,nverts)
  ((spd(n,isp),n1,nverts),mw(isp),(fam(isp,nk),nk1
  ,nrkidsp(isp),isp1,nsp)
• (i1tab(n),i3tab(n),i8tab(n),imtab(n),jmtab(n),kmt
  ab(n),bcl(n),bcf(n),bcb(n),
• idreg(n),n1,nverts)
• (iperf(n),iperd(n),n1,iper)
• (xp(n),yp(n),zp(n),i4p(n),radp(n),partn(n),up(n),
  vp(n),wp(n),tp(n),i4mom(n),
• n1,np)