Numerical Modeling and Simulation of Fluid Flow and Heat Transfer in

Engineering Applications

Son H. Ho, Ph.D.Center for Advanced Turbines and Energy Research

University of Central Florida

Room 288, Building ENG I, University of Central Florida – February 24, 2009

Agenda

1. Zero Boil-Off (ZBO) Storage of Cryogenic Liquid Hydrogen (LH2)

2. HVAC&R Indoor Spaces – Thermal Comfort and Contaminant Removal

3. Modeling and Design Micropump

4. Portable Blood Cooling System

5. Other Works

Governing Equations(Incompressible & Constant Property Fluid Flow)

• Conservation of mass:

• Conservation of momentum:

• Conservation of energy:

• Conservation of mass for water vapor:

• Conservation of mass for contaminant gas:

wDwt

waw

2/

u

0 u

refTTpt

guuuu 2

TkTt

Tcp

2

u

cDct

cac

2/

u

LH2 in Space & Automotive Applications

Centaur upper stage – liquid hydrogen/liquidOxygen propelled rocket

Transport of liquid hydrogen used in space applications.

Hydrogen tank in a car’s trunk.

Hydrogen Hummer (converted by Intergalactic Hydrogen).

Shelby Cobras (Hydrogen Car Co.)

Cryogenic Liquid Hydrogen Storage Tank with Lateral Pump-Nozzle Unit

•Fluid: LH2•3-D Model

•Steady-State Analysis

CryocoolerHeat exchanger

Controller

Solar array

Pump-nozzle unit

Tank wall

Insulation

Heat pipe

Liquid cryogen

Radiator

Condenser

EvaporatorHeat flux from surroundings

3-D Model and Dimensions

3-D Hexahedral-Element Mesh

Distribution of Velocity, m/s

Streamlines

Speed

Velocity vector and speed

Distribution of Temperature, K

(a) Conformal slice plot (b) Isosurfaces

(c) Axial planar slice plot, front (d) Axial planar slice plot, back

HVAC&R Applications

Refrigerated Warehouse

Hospital Operating Room

Refrigerated Warehouse with Ceiling Type Cooling Unit

•Fluid: Air•Two- and Three-Dimensional Models

•Steady-State Analysis

2-D and 3-D Models

2-D and 3-D Mesh

Quadrilateral Elements

Hexahedral Elements

Streamlines and Speed, m/s Temperature, °C

2-D Simulation Results

3-D Simulation Results

(a) Streamlines. (b) Speed, m/s.

(c) Pressure, Pa. (d) Temperature, °C.

Thermal Comfort Enhancement using Ceiling Fan in Air-Conditioned Room

•Fluid: Air Mixture (dry air + water vapor)•Two-Dimensional Model•Steady-State Analysis

2-D Model of Air-Conditioned Room with Ceiling Fan

2-D Simulation Results

Streamlines and speed, m/s.

Temperature, °C.

Streamlines and speed, m/s.

Temperature, °C.

(a) Ceiling fan not running (b) Ceiling fan running

3-D Simulation Results

(a) Streamlines (b) Speed, m/s

(c) Temperature, °C (d) Relative humidity, %

PMV Distributions

(a) Ceiling fan not running (b) Ceiling fan running

Thermal Comfort and Contaminant Removal in Hospital Operating Room

•Fluid: Air Mixture (dry air + water vapor + contaminant gas)•Three-Dimensional Model

•Steady-State Analysis

Three-Dimensional Model

3-D Hexahedral-Element Mesh

3-D Simulation Results

Streamlines Speed, m/s

Temperature, °C Contaminant concentration, mg/kg air

Journal1. Ho, S. H., Rosario, L., and Rahman, M. M., “Three-dimensional analysis for hospital operating room thermal comfort and

contaminant removal,” Applied Thermal Engineering (In press, available online 13 November 2008).2. Ho, S. H., Rosario, L., and Rahman, M. M., “Thermal comfort enhancement by using a ceiling fan,” Applied Thermal Engineering

(In press, available online 25 July 2008).3. Ho, S. H. and Rahman, M. M., “Nozzle injection displacement mixing in a zero boil-off hydrogen storage tank,” Int. J. Hydrogen

Energy 33 (2) (2008) pp. 878-888.4. Ho, S. H. and Rahman, M. M., “Three-dimensional analysis for liquid hydrogen in a cryogenic storage tank with heat pipe-pump

system,” Cryogenics 48 (1-2) (2008), pp. 31-41.5. Kaw, A. K. and Ho, S. H., “On introducing approximate solution methods in theory of elasticity,” Comput. Appl. Eng. Educ. 14 (2)

(2006), pp. 120-134.

Conference1. Meckler, M. and Ho, S. H., “Integrate CHP to improve overall corn ethanol economics,” Proceedings of 2008 ASME International

Mechanical Engineering Congress and Exposition, IMECE2008-66295, Nov. 2008, Boston, Massachusetts.2. Ho, S. H. and Rahman, M. M., “Transient thermal analysis of cryogenic liquid hydrogen tank with active circulation,” Proceedings

of Energy Sustainability 2007, ES2007-36195, Jun. 2007, Long Beach, California.3. Ho, S. H., Rosario, L. and Rahman, M. M., “Numerical analysis of thermal behavior in a refrigerated warehouse,” Proceedings of

2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006-15415, Nov. 2006, Chicago, Illinois.4. Ho, S. H. and Rahman, M. M., “Zero boil-off cryogenic liquid hydrogen storage tank with axial cold-spray system,” Proceedings

of 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006-15341, Nov. 2006, Chicago, Illinois.5. Rahman, M. M., Ho, S. H., and Rosario, L., “Review and some research results on hydrogen liquefaction and storage,”

Proceedings of the International Conference on Mechanical Engineering 2005, ICME2005, Dec. 2005, Dhaka, Bangladesh.6. Ho, S. H., Rosario L., and Rahman, M. M., “Effect of using ceiling fan on human thermal comfort in air-conditioned space,”

Proceedings of AIAA 3rd International Energy Conversion Engineering Conference and Exhibit (IECEC), AIAA-2005-5734, Aug. 2005, San Francisco, California.

7. Ho, S. H. and Rahman, M. M., “Three-dimensional analysis of liquid hydrogen cryogenic storage tank,” Proceedings of AIAA 3rd International Energy Conversion Engineering Conference and Exhibit (IECEC), AIAA-2005-5712, Aug. 2005, San Francisco, California.

8. Ho, S.H., Rosario, L., and Rahman, M.M., “Analysis of thermal comfort and contaminant removal in an office room with underfloor air distribution system,” Proceedings of 2005 ASME Summer Heat Transfer Conference, HT2005-72437, Jul. 2005, San Francisco, California.

9. Rahman, M. M. and Ho, S. H., “Zero boil-off cryogenic storage of hydrogen,” NHA 2005 Proceedings of Hydrogen Conference, Mar. 2005, Washington, D.C.

10. Ho, S. H., Rosario, L., and Rahman, M. M., “Predictions of relative humidity and temperature in an operating room,” Proceedings of 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE2004-61372, Nov. 2004, Anaheim, California.

Publications

Mesh Development for Indoor Environmental CFD Modeling

Geometry Decomposition and Meshing for 2-D Model

S = 0.1 m, H = 0.05 m, N = 3 and R = 1.5. 1496 square elements (58%) in total 2570 quadrilateral elements.

Geometry Decomposition for 3-D Model (1)

Geometry Decomposition for 3-D Model (2)

Meshing 3-D Model using Encapsulation Techniques (1)

Meshing 3-D Model using Encapsulation Techniques (2)

3-D Mesh: Layers of Refined Element Mesh on Fluid-Solid Interfaces

3-D Mesh: 35140 Cubical Elements (62%) in total of 56290 Hexahedral Elements

Modeling and Design Micropump

Diaphragm micropump with passive check-valves

Destination

Inlet valve

Outlet valve

Pump chamber

Pump chamber

Pump chamber

p1

p2

s s

1 1 2 2

d d

Diaphragm

Source

1

2 2

Valve discs

z

Vdead

p2*

p1*

p(t)

p(t)

ΔV

22

1 1

1

Pump chamber: mathematical model

outoutinin QQdt

dV

dt

dp

K

V

dt

dwAQQ

whA

K

dt

dpoutin

ppQin 11 22 ppQout

whAV

Pump chamber: Simulink model

Qin

Qout

1/3

zeta

0.8

h

TriangleWave Scope: w

Scope: p

Scope: Qacc

Scope: Q

Product3

Product2

Product1

Product

110000

P2

92000

P1

Outlet valve

2.23e9

K

1s

Integrator1

1s

Integrator

Inlet valve

Divide

du/dt

Derivative

1/57

C2

1/57

C1

Add1

78.54

A

ppH

pRQin

1

1

22

ppH

pRQout

Pump chamber: simulation results

Thermopneumatic micropump

Diaphragm deflection

action membraneby resisted load

3

sprestresseby resisted load

0

action bendingby resisted load

3

2 13

84

13

16

a

w

a

E

a

w

aa

w

a

Eppa

321 wBwBppa

20

4

3

214

13

16

aa

EB

42 13

8

a

EB

AwwaV 2deflection

1

0

2 du

Temperature–deflection relationship

aa h

w

p

wBwBTT 11

0

321

0

44

33

2210 1 wCwCwCwCTTa

aaa hp

BC

p

BC

hp

BC

hp

BC

0

24

0

23

0

12

0

11 ,,,

Temperature vs. deflection

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100 120Temperature rise, K

Def

lect

ion,

µm

Measured (Wego et al., 2001)

ζ = 1/2 (Wego et al., 2001)

ζ = 0.458 (s. s. edge model)

ζ = 1/3 (clamped edge model)

ζ = 0.396 (average model)

Actuation chamber: math. model

easass

sps WTTGdt

dTcm ,

dt

dwApTTGTTG

dt

dTcm afafaasas

aava ,

eaa WTTD

dt

dTD 021

3

42

32101

44

33

22102

432 wCwCwCCTD

wCwCwCwCTDW

dt

dw e

Actuation chamber: Simulink model

wInput: Heating Power

-C-

zeta

-C-

p0

0.8

h_a

308

T0

MATLABFunction

T(w)/T0

MATLABFunction

T'(w)/T0

Scope: w

Scope: W'e

Pulse

Product4

Product3

Product2

Product1

1s

Integrator

Divide3

Divide2

Divide1

Divide

-K-

D2

-K-

D1

-C-

B2

-C-

B1

Add

Actuation chamber: simulation results

Experimental data

Thermopneumatic micropump: Simulink modelw

Input: Heating Power

Qin

Qout

1/3

zeta1

1/3

zeta

0.8

h_a

0.8

h

308

T0

MATLABFunction

T(w)/T0

MATLABFunction

T'(w)/T0

Scope: w1

Scope: w

Scope: p

Scope: W'e

Scope: Qacc

Scope: Q

Pulse

Product7

Product6

Product5

Product4

Product3

Product2

Product1

Product

110000

P2

92000

P1

Outlet valve

2.23e9

K

1s

Integrator2

1s

Integrator1

1s

Integrator

Inlet valve

Divide4

Divide3

Divide2

Divide1

Divide

du/dt

Derivative

-K-

D2

-K-

D1

1/57

C2

1/57

C1

-C-

B2

-C-

B1

Add1

Add

78.54

A

Thermopneumatic micropump: simulation results

Portable Blood Cooling System

Simulation Results

(a) Three-dimensional model (b) Temperature boundary plot

(c) Temperature slice plot (d) Temperature isosurface plot

Cooling Cylinder: math. model

gv

v

fw

gvfg

fw

gvfgw

v

hmQ

m

dT

dum

dT

dumuu

dT

dvm

dT

dvmvv

T

m

m

dt

d

outout

out

1

0

011

vwv mdt

dm

dt

dmout

0dt

dT

dT

dvm

dt

dT

dT

dvm

dt

dmv

dt

dmv f

wg

vw

fv

g

gvfw

gv

wf

vg hmQ

dt

dT

dT

dum

dt

dT

dT

dum

dt

dmu

dt

dmu outout

Cooling Cylinder (Isothermal case): Simulink model

Initial conditions

Rate of vapor removed

m_v(0) & m_w(0)

f(u)

m_dot_out

30

m (g)

V-Cat

VectorConcatenate510

V (cm^3)

22.22

T0

Ug

Uf

Vg

Vf

m.

out

0

1 1

Vg Vf

Scope

T

P_satv_gv_f

u_gu_f

h_gh_f

Properties of saturated water

P_sat, kPa

1s

Integrator1

1sxo

Integrator

Dot Product

Inv

Inv

Clock

Other Works

Applied Mechanics Lab (Vietnam, 1995 – 2001)

8051-based Application (2003)

Click to play video clip

Thank You!