film condensation

7/29/2019 Film Condensation

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Department of Mechanical Engineering

Indian Institute of Technology Kanpur

Kanpur 208016

India

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Film condensation model

in the presence of

non-condensable gases

by

Mahesh Kumar Yadav

11205064



Kanpur (UP) 208 016

Film condensation model in thepresence of non-condensable

gases


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Motivation

The probability of LOCA DBA, DBA or BDBA so called severeaccidents are very low.

However, it occurs (at Fukushima-2011, Three Mile Island (TMI)-1979,US, Santa Susana Field

Laboratory-1959, US) and releases high amount of hydrogen. (eg.460 Kg of H2 in TMI-2 accident)

Most of H2 burns when averaged concentration is 7.9 vol% leads to high pressure rise andsignificantly damages the containment (Henrie and Postma, 1983, 1987).

One approach of condensation modeling is using empirical average HTC developed using volume

averaged called lumped-parameter.

Other approach is CFD based codes like MAAP, CONTAIN, GASFLOW (Travis et al., 1998),SPECTRA (Stempniewicz, 1999), MELCOR (Gauntt et al., 2000), CAST3M (Paillere et al., 2003).

CFD codes provides detailed information in such scenario but inclusion of averaged quantities and

averaged condensation rates based correlations question marked these.


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Year Incident IN ES level Country IAE A description2011 Fukushima 5 Japan Reactor shutdown after the 2011 Sendai earthquake and tsunami; failure of emergency cooling caused an explosion 2011 Onagawa Japan Reactor shutdown after the 2011 Sendai earthquake and tsunami caused a fire 2006 Fleurus 4 Belgium Severe health effects for worker at commercial irradiation facility as a result of high doses of radiation 2006 Forsmark 2 Sweden Degraded safety functions for common cause failure in the emergency power supply system at nuclear power plant 2006 Erwin US Thirty-five litres of a highly enriched uranium solution leaked during transfer2005 Sellafield 3 UK Release of large quantity of radioactive material, contained within the installation2005 Atucha 2 Argentina Overexposure of a worker at a power reactor exceeding the annual limit 2005 Braidwood US Nuclear material leak2003 Paks 3 Hungary Partially spent fuel rods undergoing cleaning in a tank of heavy water ruptured and spilled fuel pellets 1999 Tokaimura 4 Japan Fatal overexposures of wor kers following a criticality event at a nuclear facility 1999 Yanangio 3 Peru Incident with radiography source resulting in severe radiation burns 1999 Ikitelli 3 Turkey Loss of a highly radioactive Co-60 source1999 Ishikawa 2 Japan Control rod malfunction1993 Tomsk 4 Russia Pressure buildup led to an explosive mechanical failure 1993 Cadarache 2 France Spread of contamination to an area not expected by design1989 Vandellos 3 Spain Near accident caused by fire resulting in loss of safety systems at the nuclear power station1989 Greifswald Germany Excessive heating which damaged ten fuel rods1986 Chernobyl 7 Ukraine Widespread health and environmental effects. Exter nal release of a significant fraction of reactor core inventory1986 Hamm-Uentrop Germany Spherical fuel pebble became lodged in the pipe used to deliver fuel elements to the reactor1981 Tsuraga 2 Japan More than 100 workers were exposed to doses of up to 155 millirem per day radiation 1980 Saint Laurent des Eaux 4 France Melting of one channel of fuel in the reactor with no release outside the site 1979 Three Mile Island 5 US Severe damage to the reactor core 1977 Jaslovsk Bohunice 4 Czechoslovakia Damaged fuel integrity, extensive corrosion damage of fuel cladding and release of radioactivity1969 Lucens Switzerland Total loss of coolant led to a power excursion and explosion of experimental reactor 1967 Chapelcross UK Graphite debris partially blocked a fuel channel causing a fuel element to melt and catch fire 1966 Monroe US Sodium cooling system malfunction1964 Charlestown US Error by a worker at a United Nuclear Cor poration fuel facility led to an accidental criticality 1959 Santa Susana Field Lab. US Partial core meltdown1958 Chalk River Canada Due to inadequate cooling a damaged uranium fuel rod caught fire and was torn in two 1958 Vina Yugoslavia During a subcritical counting experiment a power buildup went undetected - six scientists received high doses1957 Kyshtym 6 Russia Significant release of radioactive material

to the environment from explosion of a high activity waste tank1957 Windscale Pile 5 UK Release of radioactive mater ial to the environment following a fire in a reactor core 1952 Chalk River 5 Canada Reactor shutoff rod failure with several operator errors lead to major excursion of more than double the reactor output

Nuclear Accidents:

Source: IAEA


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Level Definition People and envir onment Radiological barr iers & control Example7 Major accident Major release of radio active material with widespread health and environmental effects Chernobyl, Ukraine, 19866 Serious accident Significant release of radioactive material require implementation of planned countermeasures. Kyshtym, Russia, 19575 Accident with wider consequences Limited release of radioactive material Severe damage to reactor core Three Mile Island, 1979

4 Accident with local consequences Minor release of radioactive material Fuel melt or damage to fuel resulting in more than 0.1%release of core inventory FUKUSHIMA 1, 2011

3 Serious incident Exposure in excess of ten times the statutory annual limit for workers Exposure rates of more than 1 Sv/h in an operating area Sellafield, UK, 2005

2 IncidentExposure of a worker in excess of the

statutory annual limitsRadiation levels in an operating area

of more than 50 mSv/h Atucha, Argentina, 2005

1 Anomaly

International Nuclear Events Scale (INES):

Source: IAEA


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Objective

To analyze the condensation process in the presence of non-condensable gas with

the process parameter like mass flow rate, mixture composition, velocity, pressure

etc.


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In this presentation...

Introduction to condensation

Literature review

Parameters affecting condensation

Modeling approach

Experimental setup

General adopted correlations

Property calculation for the NCG/vapor mixture

Parametric study

Measuring devices

Summary and Conclusions


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Introduction toCondensation


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Introduction to condensation

(a) Dropwise condensation

(b) Film wise condensation

Applications:

Distillation of water

Cooling of water vapor in condenser (in power plants and

thermal power management systems)

Types of condensation


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Fig. Schematic model of film condensation

(a) Condensation in a vertical tube (b) BL without the presence of NCG (c) BL with the presence of NCG

Introduction to condensation continue


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2( )( )

2

l v

l

g yu y

3. ( )

3

l l v

l

gm

.2( )l l v

l

gd m d

dx dx

14

4

( )

l l

l l v fg

k Tx

gh

( )( ) sat wx sat w l

T Th T T k

13 4( ) 1

4

l l v fg lx

l

ghh

T x

k

Fig. Laminar film condensation without the presence

of NCG

Classical Nusselt analysisIntroduction to condensation continue


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Literature Review

D t t f M h i l E i i


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Literature review

Outline:

Parameters affecting condensation

Modeling approach

Experimental setup

General adopted correlations


D t t f M h i l E i i


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Primary NCG mass fraction, subcooling,

superheating, operating pressure, flow

direction

Secondary

Suction effect, mist formation, film

waviness or roughness

TertiaryEffect of NCG used like argon, helium and

the condensing surface orientation.

Based on how frequently a parameter considered in the literature, they can be classified as:

Parameters affecting condensationLiterature review continue



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Types of approach

Boundary layer

solution

Based on solving boundary layer (NCG/vapor BL and condensate film BL)

equations with appropriate interfacial jump and boundary conditions (Similarity

variable, computational and mechanistic approach)

Heat and mass

transfer analogy

Based on heat balance at the liquid-gas interface where interface temperature is

determined iteratively (Empirical and mechanistic approach)

Diffusion theory

Conductivity of condensation (kcond) is calculated using either Clausius-

Clapeyron equation or HMTA. Then condensation HTC is calculated on the basis

of that kcond .

Experimental Finding out correlations based on the experimental datas (Empirical approach)

Modeling approachLiterature review continue

Department of Mechanical EngineeringFil d ti d l


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Equations Liquid film region Vapor /gas region

Conservation of

massDiffusion

equation

Conservation of

momentum

Conservation of

energy

( ) ( ) ( )m m m mu

u u v u g x y y y

( ) ( ) 0l lu vx y

( ) ( )l l l l u

u u v u g x y y y

( ) ( ) 0m m

u vx y

"

( ) ( ) ( )pm m m pg pv gT q

c u T v T c c j

x y y y

( ) ( )pl l l l Tc u T v T k x y y y

2" *

( ) mg D m gg v

MHere q k T R T j

y M M

* (1 )

Here ( ) ( ) jD g g

g m g m g v

W Wj D W D T and j

y T y

( ) ( )g

m m

ju W v W

x y y

(i) Governing equations

Boundary layer solutionModeling approach continue

Department of Mechanical EngineeringFilm condensation model


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Condition Equation

Mass flux

Stream wise

velocity

Temperature

Interfacial shear

Energy flux

(ii) Interface conditions

Boundary layer solution continue

. . . .

g vlm M M M

, ,l mu u

, ,l mT T

0my

uy

."

l fg

Tk M h q

y

(iii) Interface constraintConstraint Equation

Impermeable

interface to NCG

Saturation state @

interface Ti =Tsat,v

.

0gM

(iv) Boundary conditions

Condn Equation

At y=0 u=v=0; T=Tw

At

At

y .; li m

dT T m u v

dx

y ,; g gu u W W



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Heat and mass transfer analogy

Heat balance at the interface

Total heat transfer coefficient

Condensate film thickness

Since, we know that

1

1 1tot

f c s

hh h h

( ) ( )( )f i w c s ih T T h h T T

4* 3

12 2 3 3

1 2 3 1 2 3 4 1 2

1.259

( ) ( ) ( )

Nu

p i i pa a x a x l b b x b x b x m c c x

.

; h ; h( )

fgl mf s m c

i b i

m hk kh Nud T T

hm is calculated using Shm relationas given below.

,

, .

nc i

m

nc i nc b

WmdSh

D W W

Modeling approach continue



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Diffusion theory

The condensation conductivity is given as

or

, , ,

,

using HMTAfg i nc i nc bavgcondb i nc i

W WDHkT T W

Then the condensation HTC is calculated as

Peterson et al (1993)condcondSh k

h

L

2 2 2 2

2 3 2 2

1 1et al (1993); et al (1998)

tot v fg tot v fg

cond cond

avg i b

P M h D P M h Dk Peterson k Herranz

R T R TT

Modeling approach continue



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p g g


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Interface shear stress consideration

(i) McAdams modifier (1951)

where 1.28 for Re 30; =1.0 for Re 30( )

lf

hx

k

(ii) Blangetti et al model (1982)

14 4 4

, ,

f

x x la x tu

l

h LNu Nu Nu

k

* *2*3*

, *

Re1where comes from equation

3 21

f g

x lag

l

Nu

Where Nux,la is Local laminar Nusselt number given by

and Nux,tu is Local turbulent film Nusselt number given by

*

, Re Pr (1 ) wh values of a, b, c, d, e, f is given in above table.b c f

x tu f gNu a e ere

Special considerationsLiterature review continue



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g g


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Film roughness consideration

Special considerations continue

0.215

, ,

0.215 0.25

, ,

where n=0.68Pr

where n=0.68Sc ; f 0.0791Re

n

r

or x os xs

n

ror x os x s

s

fNu Nu

f

fSh Sh

f

Correction suggested by Norris (1970)

Three popular models for estimating the roughness of the condensate are

(i) Moody correlation (1944)

(ii) Wallis correlation (1969)

(iii) Haaland correlation (1990)

13

3 2 1001.375 10 1 21.544

Rerf

d

1 300r sf fd

Suction effect consideration Kays and Moffat correlation (1975)

1 1.

, ,. 12 2, 3

.

,

(Re 1000)Pr2Re Pr exp 1 where Nu Nu 3.66

Re Pr 1 12.7 Pr 12

Reexp

s

x x mx o x o x

m o x x sx

x xx

m o

f

m GNu

G Nu fm

m ScSh

G Sh

1 1

6

, ,. 12 2

3

(Re 1000)2

1 where Sh for 2300 Re 5 10 ; Sh 3.66 for Re 2300

Re 1 12.7 12

s

mo x o x

x x sx

fSc

G

fm Sc Sc

1.11

1012

1 6.91.8log

Re 3.7r

d

f



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Developing flow consideration

Reynolds et al (1969): It is assumed that the temperature and concentration profile developsimultaneously. 3

4 2

,

34 2

,

0.8(1 7 10 Re )1

0.8(1 7 10 Re )1

xot o x

xot o x

Nu Nux

d

Sh Shx

d

Turbulent modelTurbulent viscosity is given as:

Prandtl mixing length theory

Kato et al (1968)

2

t m

uL

y

20.4 1 exp 0.0017( )

sing assumption: at y= ; u 0 (Chen C. K., 2009)

t

L m

y y

u

Special considerations continue



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Vierow, K. et al, Horizontal Heat Exchanger Design and Analysis for Passive Containment HeatRemoval System, U. S. Department of Energy, Nuclear Engineering Education Research, Final

Technical Report, 2002 through 2005

Experimental setup


I di I tit t f T h l KFilm condensation model


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Oh, S., and Revankar, S.T., Effect of noncondensable gas in a vertical tube condenser, International

Journal of Nuclear Engineering and Design, vol. 235, pp. 16991712, 2005

Experimental setup continue


Indian Instit te of Technolog Kanp rFilm condensation model


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Lee, K.Y., and Kim, M.H., Effect of an interfacial shear stress on steam condensation in the presence

of a noncondensable gas in a vertical tube, , International Journal of Heat and Mass Transfer, vol. 51,

pp. 53335343, 2008

Experimental setup continue


Indian Institute of Technology KanpurFilm condensation model

i th f


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Wilke and Lee (1955)

Rao et al (2008)

Bucci et al (2008)

Holman (1992)

Kays et al (2005)

Herranz et al (1998)

10 2.072

8.2

1.87 10

7235exp 77.3450 0.0057

v

TD

P

TTP

T

". , ,

m

,

ln(1 ) where B =1

v i v bv m

v i

w wm K Bw

10.75 3

10.75 3

1.04 0.0395 Re Pr

1.04 0.0395Re

o

o

Nu

Sh Sc

213

1

0.046 where Ra=GrPr= ( )

Nu with n=3 (Churchill, 1977)

p

buo w cw

n n n

combined force natural

g C bNu Ra T T

k

and Nu Nu

where is suction factor

i

nc avg

o avg

nc

X TSh Sh

X T

32

4

, 2

, ,

1 1

1 110 1.084 0.249( ) ( / )

a b

a b

a b a b a b

T

M MDM M P r f kT

General adopted correlationsLiterature review continue



i th f


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Property Binary mixture Multi-component mixture

Diffusion coefficient

Grashof number

Viscosity

Specific heat

Thermal conductivity

Mass fraction of NCG

Mole fraction of NCG

2.072

53.4439 10 (Cenzel, 2002)

avg

tot

TD

P

,

,1/

g avg

eff n

j avg jvj

xD

x D

3

gb gi gb

2

g ( - )L(Herranz et al, 1998)Gr

x nc nc v v x= W +W (T ) '1

1

( )= (Reid et al, 1987)

1 ( / )

ni avg

m ni

ij j ij

T

D x x

1

1

( )= (Reid et al, 1987)

1 ( / )

ni avg

m ni

ij j ij

k Tk

A x x

x nc nc v v= W +W (T )vk k k

px nc pnc v pv= W +W (T )vC C C

,

( ) / ( ) ( / )

1 ( ) / ( ) ( / )

T v x v x nc v

nc x

T v x v x nc v

P P T P T M Mw

P P T P T M M

,

,

T s nc

nc x

T

P Px

P

,

(Peterson, 2000)

ln

jb ji

j ave

jb

ji

x xx

xx

Literature review continue




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Parametric study



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Parametric study continue



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t e p ese ce o


Important findings

Steam and NCG flow side Cooling water flow side

Pressure range: 1-2.5 atm

Then Tsat:100-1270C

Length of the plate: 70

cm

Film thickness: 0.18 mm

Condensate mass: 15.5

gm/s=55.8 kg/hr

Inlet temperature: 25 0C

Outlet temperature: 27 0C

Then temp. difference: 2 0C

Heat transfer required: 35

kW

Corresponding Mass flow

rate required: 4.2

kg/s=15120 kg/hr

Steam and NCG flow side Cooling water flow side

Pressure range: 1-2.5 atm

Then Tsat:100-1270C

Length of the plate: 50 cm

Film thickness: 0.17 mm

Condensate mass: 13gm/s=46.8 kg/hr

Inlet temperature: 25 0C

Outlet temperature: 27 0C

Then temp. difference: 2 0C

Heat transfer required: 30

kW

Corresponding Mass flow

rate required: 3.7

kg/s=13320 kg/hr




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p


Measuring Devices



K 208016


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Measuring devices

Mass flow rate measurement

Film thickness measurement

Gas concentration measurement



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Can measure the mass flow rate of any gas or liquid, ideally suited for saturated andsuperheated steam.

Measure five process parameters at the same time: mass flow rate, temperature, pressure,

volumetric flow rate, and fluid density.

Hydrogen flow meter

Steam flow meter

Mass flow rate measurementMeasuring devices continue



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Model Thickness range Model Thickness range

F20 15nm - 100m F50 20nm - 100m

F20-UV 01nm - 40m F50-UV 5nm - 40m

F20-NIR 100nm - 250m F50-NIR 100nm - 250m

F20-EXR 15nm - 250m F50-EXR 15nm - 250m

F20-UVX 1nm - 250m F50-UVX 5nm - 250m

F20-XT 10nm 1mm F50-XT 10nm 1mm

F70 15nm 13mm F50-CTM-NIR 0.1nm 2mm

Film thickness measurementMeasuring devices continue

Film thickness is measured as:

R={(n-1)2+k2}/{(n-1)2+k2}

Where R= Reflection

n=film refractive index

K=film extinction coefficient



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d bl


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Gas concentration measurementMeasuring devices continue

Quadrupole Mass Spectrometers (QMS) is kind of ionisation gauge with separation system

(according to mass to charge ratio) for the different species.

QMS operates best at 10-6 mbar.

Fig. Gas concentration measurement system in

PANDA

Fig. Mass spectrometry in TOSQAN



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non condensable gases


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Gas concentration measurement continue

Fig. PANDA calibration system

Difficulties in measurements:

Steam get condensed and may adsorbed

in the capillary section. To avoid this capillary

tubes are heated upto 150 C.

The pressure inside the test section is quite

high. It needs to be reduced as low as 10-6

mbar for best working of QSM.

As the pressure inside the chamber is notconstant. So, the time required to feed the

sample to the QSM is different. Due to this,

calibration is required again.

The increase in feeding time of sample

leads to the possibility of leakage.



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Summary and

conclusions



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Summary and Conclusions

It has been noted that no full mechanistic model available in the literature. Either they are based on

some correlations or giving some kind of input from the experiment.

Condensate film thickness is of the order of 0.001-1 mm for the plate length of 50-70 cm.

Condensate film thickness (order of 0.001-1 mm ) can be measured using optical technique. This

technique can also be used for measuring the roughness of the film.

The gas concentrations is measured using a device called Quadrupole Mass Spectrometers (QMS).

Calculation of mixture composition for vapor and gas is a uphill task as not only the transfer of

sample from test section to QMS involves many complexities but also QMS requires samples at

nearly vacuum for best measurement.

With all such difficulties, its great satisfaction that the setup is feasible in our laboratory.



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Quotation of the instruments

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End of Presentation

film condensation

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