week4_ch7_cfd

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Multiscale simulation

for adsorption process development

[Ch. 7]

Major: Interdisciplinary program of the integrated biotechnology

Graduate school of bio- & information technology

Youngil Lim (N110), Lab. FACS Youngil Lim (N110), Lab. FACS

phone: +82 31 670 5200 (secretary), +82 31 670 5207 (direct)phone: +82 31 670 5200 (secretary), +82 31 670 5207 (direct)

Fax: +82 31 670 5445, mobile phone: +82 10 7665 5207Fax: +82 31 670 5445, mobile phone: +82 10 7665 5207

Email:Email: [email protected] [email protected] , homepage:, homepage: http://hknu.ac.kr/~limyi/index.htmhttp://hknu.ac.kr/~limyi/index.htm



Ch. 7. Computational methods on Mesoscopic/Macroscopic scale

+Euclidean space in classical mechanics

+Hilbert space in quantum theory

+Sobolev space in fluid or solid mechanics ++-space in thermodynamics

+non-Euclidean curved space and time in general relativity

theory

+Minkowski space in special relativity theory



Equations linkage in CFD

Thermal Decomposition in a Parallel Plate Reactor



Introductions

Chemical Engineering Module

± Fully coupled momentum, energy and mass transport

± Strategies for Multiphysics modeling

Inlet

outlet

Heated cylinder

R O O

R

R O H

R O H

A Fk



Coupled Three phenomena

Momentum

(Navier-Stokes Equations)

Energy

(Convection and Conduction, Heat transfer)

Mass

(Convection and Diffusion, Reaction)

Velocity, pressure

Temperature

Density, viscosity

Thermal conductivity

Heat capacity

Reaction rate

(Re=4) (C A/C= 0.02)

reaction rate =r(CA)(exothermic or endothermic)

Concentration



1 ± One-way coupled

The momentum transport is independent of the energyand mass transport

The energy transport depends only on the momentum

transport

The mass transport depends on both the momentumtransport and the energy transport

The heat of reaction, Q, is neglected

momentum Heat

Mass

Sequential solution approach

(1)

(3)

(2)



Momentum : Navier-stokes equations

0!

!x

x F p

t

T uuuu

u VL V

Energy : Convection and Conduction

T C QT k t

T C P P !

x

xu V V

Mass : Convection and Diffusion

iiiii c Rc Dt

c

x

xu

u

T

i

g

i cT R

E A R

¹¹

º

¸

©©

ª

¨ ! exp

Ci







Simulation procedure in COMSOL

/

Model Navigator (Momentum / Heat / Mass Transport)

CAD

(1D, 2D or 3D)

Subdomain / Boundary Settings

(Momentum / Heat / Mass Transport)

Mesh

Solver (processing)

Post-processing



Coupled Three phenomena

Momentum

(Navier-Stokes Equations)

Energy

(Convection and Conduction, Heat transfer)

Mass

(Convection and Diffusion, Reaction)

Velocity, pressure

Temperature

Density, viscosity

Thermal conductivity

Heat capacity

Reaction rate

reaction rate =r(CA)(exothermic or endothermic)

Concentration





Results - Temperature

Sequential

(constant parameters: V, L, k, Cp, Q)

Simultaneous

(time dependent parameters)



Results - Concentration

Sequential

(constant parameters: V, L, k, Cp, Q)

Simultaneous

(time dependent parameters)



T C QT k t

T C

P P !

x

xu V V


0!

!x

x F pt

T uuuuu VL V



ii

iiiii

Rt

n

c Rc Dt

c

!x

x

!x

xu

u(t,x,r)

T(t,x,r)

ii

iiimi

C K n

nnk R

!

!

*

*

,)(

Ci(t,x,r)

External linage in Multiscale simulation for adsorption problems

ni(t,x,r)



T C QT k t

T C

P P !

x

xu V V


0!

!x

x F pt

T uuuuu VL V



ii

iiiii

Rt

n

c Rc Dt

c

!x

x

!x

xu

u(t,x,r)

T(t,x,r)

ii

iiimi

C K n

nnk R

!

!

*

*

,)(

Ci(t,x,r)


ni(t,x,r)Q: adsorption heat

Di: axial/radial diffusivity

k m,i: mass transfer coeff.K : adsorption heat






Tools for calculation

FS

Fluid dynamics simulation

Internal coupling Velocity, u: Mm-H-M

Fluid density, V(T): Mm-H

Viscosity, Q(T): Mm-H

Heat capacity, C p(T): H-H

Thermal conductivity, k (T): H-H

Adsorption kinetics, R i(T): H-M

Adsorption heat, Q(R i): M-H

Axial/radial diffusivity, Di(T): H-M

External coupling

Adsorption isotherms, ni(T, Ci): MS-

FS

Adsorption heat, Q(T): MS-FS Pore diffusivity, D pore: MS-MFS-FS

Geometry effects of equipments: FS-

PS

Momentum

(Mm)Heat (H)

Mass (M)

P S

Process simulation

MFS

Micro-flow dynamics simulation

MS

Molecular simulation

1D Mass balance

(1DM)

Boundary conditions

(Node model, NM)

Internal coupling

Operating conditions (X, Qi): NM-

1DM

Design parameters (Lc, Dc, Ni, I b):

NM-1DM

Computational parameters ( Nmesh, (z,

(t): NM-1DM

External coupling (Model

parameters)

Adsorption isotherms, ni(T, Ci): MS-

PS

Mass transfer coefficient, k (T): MS-MFS-PS

Axial dispersion coefficient, Dax: FS-

PS

Molecular force field

(MFF, e.g., COMPASS)

Internal coupling

Molecular formulation: Predefined input

(experiment)

Particle Density, V p: MFF

Specific surface area, A: MFF

Porosity, I p: MFF

Adsorption heat, Q(T): MFF-GCMC

Adsorption isotherms, ni(T, pi): MFF-GCMC

Pore size distribution (PSD): MFF-GCMC Pore diffusivity, D pore(T): MFF-NVT

External coupling

Force field parameters from DFT

(density functional theory) or ab-init io methods

Grand Canonical Monte Carlo

(GCMC)

NVT molecular dynamics

(Canonical ensemble; NVT)

Dissipative particle dynamics

(DPD)

Lattice Boltzmann Method

(LBM)

Internal coupling (?)

Pressure drops, ( p: LBM

Pore diffusivity, D p(T): LBM-

DPD

External coupling(?)

Adsorption isotherms, ni(Ci):

MS-MFS

Pore size distribution: MS-MFS

MaterialStudio (Accelrys Inc.,

USA)

Forcite Plus & Sorption modules

COMSOL Multiphysics

(Comsol Inc., Sweden)

COMSOL Multiphysics

(CFD standard)

FAST-Chrom/SMB

(CESE PDE solver)

DFT(GAUSSIAN)

MC/MD(Accelrys)

Coarse-grainedparticle simulation

Lattice-Boltzmannsimulation

CFD(Comsol/Fluent)

Process model(FAST-Chrom/SMB)



)(

1

, iiii

ii

b

biii

nC K k t

n

c Rc Dt

c

!x

x

!x

x

uI

I

Mass (process model) : Convection and Diffusion + node model

Ci(t,x,r)


ni(t,x,r)

Di: axial diffusivity

k m,i: mass transfer coeff.

K : adsorption heat

°¯®

!!

!!!

) z ,0t ( n )0 , z( n

) z ,0t ( C )0 , z( C IC

init ial

init ial

±±

°

±±

¯

®

!x

x

x

x!

!

!

!

!

t ,0 z

C

t , z

C DC C v

BC

c L z

0 z

axin0 z L

±°

±¯

®

!

!|

r aff inatenod eine xt r act

nod eind esor bent d esor bent f eed f eed

nod ein

nod eininin

r aff inatee xt r act d esor bent f eed nod ein

nod eout in

QC QC QC QC QC QC

QQQQQQQ

H K FE

H K FE

Operating conditions: X, Qdesorbent, Qextract, Qfeed, Qraffinate

Column model

Node model



Ch 7. Mesoscale to Macroscale

Ch 7. Computational methods on

mesoscopic & macroscopic scale

± FEM

± Dissipative particle dynamics

± Theory of elasticity

± «

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week4_ch7_cfd