Two Phase Flow Pattern and Flow Pattern

Laboratoire de Transfert de Chaleur et de Masse

ECOLE POLYTECHNIQUEFEDERALE DE LAUSANNE



Describe two-phase flow patterns for flows inside horizontal and vertical tubes.

Show some videos of two-phase flows. Present flow pattern maps for vertical tubes. Present flow pattern maps for horizontal tubes. Describe two-phase flows on the outside of tube

bundles. Show flow pattern map for horizontal tube

bundles.



Fig. 12.1. Missing Mist Flow, which is numerous smallliquid droplets dispersed in continous vapor phase.



Bubbly flow. Numerous bubbles are observable as the gas is dispersed in the form of discrete bubbles in the continuous liquid phase. The bubbles may vary widely in size and shape but they are typically nearly spherical and are much smaller than the diameter of the tube itself.

Slug flow. With increasing gas void fraction, the proximity of the bubbles is very close such that bubbles collide and coalesce to form larger bubbles, which are similar in size to the tube diameter and have a characteristic shape similar to a bullet with a hemispherical nose and a blunt tail. They are commonly referred to as Taylor bubbles. These bubbles are separated by slugs of liquid, which may include small entrained bubbles. Taylor bubbles have a thin liquid film between them and the tube wall, which may flow downward due to gravity, even though the net flow of fluid is upward.

Churn flow. Increasing the velocity of the flow, the structure of the flow becomes unstable with the fluid travelling up and down in an oscillatory fashion but with a net upward flow. The instability is the result of the relative parity of the gravity and shear forces acting in opposing direction on the thin liquid film surrounding Taylor bubbles. This flow pattern is in fact an intermediate regime between the slug flow and annular flow regimes. Churn flow is typically a flow regime to be avoided in two-phase transfer lines, such as those from a reboiler back to a distillation column or in refrigerant piping networks, because the slugs may have a destructive consequence on the piping system.



Annular flow. Once the interfacial shear of the high velocity gas on the liquid film becomes dominant over gravity force, the liquid is expelled from the center of the tube and flows as a thin film on the wall (forming an annular ring of liquid) while the gas flows as a continuous phase up the center of the tube. The interface is disturbed by high frequency waves and ripples. In addition, liquid may be entrained in the gas core as small droplets, so much so that the fraction of liquid entrained may become similar to that in the film. This flow regime is particularly stable and is the desired flow pattern for two-phase pipe flows.

Wispy annular flow. When the flow rate is further increased, the entrained droplets may form transient coherent structures as clouds or wisps of liquid in the central vapor core.

Mist flow. At very high gas flow rates, the annular film is thinned by the shear of the gas core on the interface until it becomes unstable and is destroyed, such that all the liquid in entrained as droplets in the continuous gas phase, analogous to the inverse of the bubbly flow regime. Impinging liquid droplets intermittently wet the tube wall locally. The droplets in the mist are often too small to be seen without special lighting and/or magnification.



Fig. 12.3. Not all flow regimes arenecessarily encountered dependingon flow conditions.

MistFlow



Fig. 12.4. Note that it is presented in U.S. units.

( )sftlbm 2=&

5.0

L

G

5.0

G

L9.0

x1x



Example Calculation: A two-phase fluid is flowing upwards in a vertical pipe of internal diameter of 1.0 in. The fluid properties are as follows: liquid density = 60 lb/ft3; vapor density = 2 lb/ft3; liquid viscosity = 0.4 cp; vaporviscosity = 0.01 cp. If the vapor quality is 0.2 and the total flow rate of liquid and vapor is 3600 lb/h, using the Fair flow pattern map, what is the local flow pattern expected to be?

Solution: The mass flow rate of 3600 lb/h is equivalent to 1.0 lb/s. Theinternal diameter is 1 in. = 1/12 ft. The mass velocity is then obtained by dividing the mass flow rate by the internal cross-sectional area of the tube, such that the mass velocity = 183.3 lb/ft2s. The parameter on the x-axis of the Fair map is:

Thus, using the values of 183.3 and 1.09 on the map, the flow regime is identified to be annular flow.

09.14.001.0

260

2.012.0

x1x 1.05.09.0

1.0

L

G

5.0

G

L9.0

=

=



Fig. 12.5. Dual units shown.



Fig. 12.2. Missing Mist Flow, whichis numerous small liquid dropletsdispersed in continous vapor phase.

Note: plug and slug flows are often regrouped into one category: intermittent flow



Two-phase flow patterns in horizontal tubes are similar to those in vertical flows but the distribution of the liquid is influenced by gravity that acts to stratify the liquid to the bottom of the tube and the gas to the top. Flow patterns for co-current flow of gas and liquid in a horizontal tube are shown in Fig. 12.2 and are categorized as follows:

Bubbly flow. The gas bubbles are dispersed in the liquid with a high concentration of bubbles in the upper half of the tube due to their buoyancy. When shear forces are dominant, the bubbles tend to disperse uniformly in the tube. In horizontal flows, theregime typically only occurs at high mass flow rates.

Stratified flow. At low liquid and gas velocities, complete separation of the two phases occurs. The gas goes to the top andthe liquid to the bottom of the tube, separated by an undisturbed horizontal interface. Hence the liquid and gas are fully stratified in this regime.



Intermittent flow. Further increasing the gas velocity, these interfacial waves become large enough to wash the top of the tube. This regime is characterized by large amplitude waves intermittently washing the top of the tube with smaller amplitude waves in between. Large amplitude waves often contain entrained bubbles. The top wall is nearly continuously wetted by the largeamplitude waves and the thin liquid films left behind. Intermittent flow is also a composite of the plug and slug flow regimes. These subcategories are characterized as follows:Plug flow. This flow regime has liquid plugs that are separated by elongated gas bubbles. The diameters of the elongated bubbles are smaller than the tube such that the liquid phase is continuous along the bottom of the tube below the elongated bubbles. Plug flow is also sometimes referred to as elongated bubble flow.

Slug flow. At higher gas velocities, the diameters of elongated bubbles become similar in size to the channel height. The liquidslugs separating such elongated bubbles can also be described aslarge amplitude waves.



Stratified-wavy flow. Increasing the gas velocity in a stratified flow, waves are formed on the interface and travel in the direction of flow. The amplitude of the waves is notable and depends on the relative velocity of the two phases; however, their crests do not reach the top of the tube. The waves climb up the sides of the tube, leaving thin films of liquid on the wall after the passage of the wave.Annular flow. At even larger gas flow rates, the liquid forms a continuous annular film around the perimeter of the tube, similar to that in vertical flow but the liquid film is thicker at the bottom than the top. The interface between the liquid annulus and the vapor core is disturbed by small amplitude waves and droplets may be dispersed in the gas core. At high gas fractions, the top of the tube with its thinner film becomes dry first, so that the annular film covers only part of the tube perimeter and thusthis is then classified as stratified-wavy flow.Mist flow. Similar to vertical flow, at very high gas velocities, all the liquid may be stripped from the wall and entrained as small droplets in the now continuous gas phase.



Fig. 12.6. Note that it is presented in dual units.

2/1

=

water

L

air

G

3/12

=

L

water

water

Lwater

water = 1000 kg/m3;air = 1.23 kg/m3;water = 0.001 Ns/m2;water = 0.072 N/m.



Fig. 12.7. Use following Eqs.



( )( )

2/1

G

L

dz/dpdz/dpX

=

( )[ ] 2/1gdmFr

iGLG

GG =

&

( )( )

2/1/

= GLL

gdzdp

T 2/1ReLGFrK =

L

iLL

dmRe =&

G

iGG

dmRe =&

( )ik

kkk d

mdzdp 22/

&=

kk Re

16=

4/1Re079.0

kk =



Example 12.3: Determine the local flow pattern at the following qualities (0.05, 0.25, 0.50, 0.75 and 0.95) for a fluid flowing in a horizontal tube of 22 mm internal diameter whose flow rate is 0.1 kg/s. Physical properties: liquid density is 1200 kg/m3, gas density is 20 kg/m3, surface tension is 0.012 N/m and the liquid and vapor dynamic viscosities are 0.0003 Ns/m2 and 0.00001 Ns/m2.

0.05 0.25 0.50 0.75 0.95 Gm& 13.16 65.79 131.6 197.4 250.0 Lm& 250.0 197.4 131.6 65.79 13.16

ReG 28952 144760 289520 434280 550088 G 0.00606 0.00405 0.00341 0.00308 0.00290 (dp/dz)G -4.77 -79.68 -268.4 -545.5 -823.9 ReL 18336 14476 9651 4825 965 L 0.00679 0.00720 0.00797 0.00948 0.01660 (dp/dz)L -32.1 -21.3 -10.5 -3.11 -0.218 X 2.60 0.516 0.197 0.0755 0.0163 FrG 0.184 0.922 1.84 2.77 3.50 T 0.053 - - - - K - - - - - Pattern Intermittent Annular Annular Annular Annular

=x



Fig. 12.8. Not all flow regimes are necessarily encountered.



Existing Map for Adiabatic and Evaporating Flows.

0

100

200

300

400

500

600

700

0.0 0.2 0.4 0.6 0.8 1.0

V apor quality

SSW

I A

M FR 134a D =12mm Tsat=10C

q=15 kW /m2

q=0 kW /m2

G m is t

G w a v y

G s t ra t

X I A



History of this map: Work began in 1992 to get flow pattern data; Objective was to obtain an accurate but user friendly map; We modified Steiner VDI adiabatic map, who used R-12 & R-22

data to modify Taitel-Dukler map; Our map is based on our data for R-134a, R-123, R-502, R-402Aand R-404A for 100



Flow pattern map observations:Parameter ranges: 12.0 Tube I.D. 14.0 mm, 1.12 Psat 8.9 bar, 0.0085 Pr 0.225, 16.3 mass velocity 500 kg/m2s, 0.01 x 0.99, and 440 q 58,000 W/m2.Fluids: R-123, R-134a, ammonia, R-502, R-402A, R-404A and R-407C (over 1000 observations; now also R-22 and R-410A in 8 and 13.8 mm tubes).

Notes: Bubbly flow transition has not been tested at all;Mist flow transition is part of current Ph.D. study;Wider range of Diameters is under study;Higher Reduced pressures are under study.



Geometric eqs: Fig. 12.10:di

h

AGPG

AL PL

PiLd

iLd

L

iGd

G

iid

i

iLd

L

iGd

G

ih

hd P

Pd P

Pd P

Pd A

Ad

AAd

= = = = = =, , , , ,2 2

For hLd 0.5:

( ) ( )( )

( )( ) ( )Ld Ld Ld Ld Gd Ld

Ld Ld Ld Ld Ld Gd Ld

P h h h P P

A h h h h A A

= =

= + =

8 2 1 3

12 1 8 154

0 5 0 5

0 5 0 5

. .

. .

,

,

[12.4.13]

For hLd > 0.5:

( ) ( )( )

( )( ) ( ) ( )Gd Ld Ld Ld Ld Gd

Gd Ld Ld Ld Ld Ld Gd

P h h h P P

A h h h h A A

= =

= + =

8 1 2 1 3

12 1 8 1 1 154

0 5 0 5

0 5 0 5

. .

. .

,

,

[12.4.14]

For 0 hLd 1: ( )( )id Ld LdP h h= 2 1 0 5. [12.4.15]



Geometric eqs., cont.:Since h is unknown, an iterative method utilizing the following equation isnecessary to calculate the reference liquid level hLd:

tt Gd idGd

Gd id

Gd

id

Ld LdLd

LdX

P PA

P PA

PA P

AP

21 4 2

2

1 4 3

26464= +

+ +

[12.4.16]

Once the reference liquid level hLd is known, the dimensionless variables arecalculated from Eqs. (12.4.13) to (12.4.15) and the transition curves for the newflow pattern map are determined with Equations (12.4.1) to (12.4.11). This map was developed from a database for five refrigerants: two single-component fluids (R-134a and R-123), two near-azeotropic mixtures (R-402A and R-404A) and one azeotropic mixture (R-502). The test conditions coveredthe following range of variables: mass flow rates from 100 to 500 kg/m2s, vapor qualities from 4-100%, heat fluxes from 440 to 36500 W/m2, saturationpressures from 0.112 to 0.888 MPa, Weber numbers from 1.1 to 234.5, andliquid Froude numbers from 0.037 to 1.36. The Kattan-Thome-Favrat flow pattern map correctly identified 96.2% of these flow pattern data.



The transition boundary curve between annular and intermittent flows to stratified-wavy flow is:

( ) ( ) 501FrWex1h25)1h2(1xdgA16

m)q(2F

L

)q(1F2Ld

2

Ld2 5.02 2

GLi3Gd

5.0

wavy +

+

=

&

[12.4.1]

The high vapor quality portion of this curve depends on the ratio of the Froudenumber (FrL) to the Weber number (WeL), where FrL is the ratio of the inertia to the surface tension forces while WeL is the ratio of inertia to gravity forces.The mass velocity threshold for the transition from annular flow to mist flow is:

=WeFr

x

dgA7680m

LPh2 2

GLi2Gd

5.0

mist&

[12.4.2]

Evaluating the above expression for the minimum mass velocity of the mist flowtransition gives the value of xmin, which for x > xmin: minmist mm && = [12.4.3]



The transition between stratified-wavy flow and fully stratified flow is given bythe expression

( ) ( )

( )

= 32 LGLG

2GdLd

2

x1x

gAA3.226m

3/1

strat&

[12.4.4]

The transition threshold into bubbly flow is

( )

( )

=

L25.0

id275.1

GLi25.1

L2LdGd

Px13164.0

gdAA256m

75.1/1

bubbly&

[12.4.5]

In the above equations, the ratio of We to Fr is

L

i LWeFr

g d

=

2

[12.4.6]

and the friction factor is

2

LdPh A5.1

log2138.1

+=

[12.4.7]



The non-dimensional empirical exponents F1(q) and F2(q) in the wavym& boundary equation include the effect of heat flux on the onset of dryout of the annular film, i.e. the transition ofannular flow into annular flow with partial dryout, the latter which is classified as stratified-wavy flow by the map. They are:

+

=

qq8.64

qq0.646)q(F

DNBDNB

2

1

[12.4.8a]

023.1q

q8.18)q(FDNB

2 +

=

[12.4.8b]

Note: In recent unpublished work covering a wide range of heat fluxes at high vapor qualities,we have found that the heat flux effect in the above two expressions is too strong andrecommend using q/2 in place of q in the above two expressions. The Kutateladze (1948)correlation for the heat flux of departure from nucleate boiling, qDNB is used to normalize the local heat flux:

( )[ ]= GL 4/1LGG 2/1DNB gh131.0q [12.4.9]



The vertical boundary between intermittent flow and annular flow is assumed to occur at a fixed value of the Martinelli parameter, Xtt, equal to 0.34, where Xtt is defined as:

=

G

L

L

G125.05.0875.0

tt xx1

X

[12.4.10]

Solving for x, the threshold line of the intermittent-to-annular flow transition at xIA is:

+

=

12914.0xG

L7/1

L

G75.1/1

1

IA

[12.4.11]

Figure 12.10 defines the geometrical dimensions of the flow where PL is the wetted perimeter of the tube, PG is the dry perimeter in contact with only vapor, h is the height of the completely stratified liquid layer, and Pi is the length of the phase interface. Similarly AL and AG are the corresponding cross-sectional areas.



Zrcher, Thome and Favrat (1997) obtained additional two-phase flow pattern observationsfor the zeotropic refrigerant mixture R-407C at an inlet saturation pressure of 0.645 MPa andthe map accurately identified these new flow pattern data. Zrcher, Thome and Favrat (1999) also obtained two-phase flow pattern data for ammonia with a 14 mm bore sight glass formass velocities from 20 to 140 kg/m2s, vapor qualities from 1-99% and heat fluxes from 5000 to 58000 W/m2, all taken at a saturation temperature of 4C and saturation pressure of 0.497MPa. Thus, the mass velocity range in the database was extended from 100 kg/m2s down to 20 kg/m2s. In particular, it was observed that the transition curve stratm& was too low and Eq. (12.4.4), was empirically corrected by adding +20x as follows:

( ) ( )( ) x20x1x

gAA3.226m31

32LGLG

2GdLd

2

strat +

=&

[12.4.17]

where stratm& is in kg/m2s. The transition from stratified-wavy flow to annular flow at highvapor qualities was instead observed to be too high and hence an additional empirical term with an exponential factor modifying the boundary at high vapor qualities was added toEquation (12.4.1) to take this into account as:

( )( )

= x1x97.0x

wavy)new(wavy

22

e75mm && [12.4.18]

where the mass velocity is in kg/m2s.



In addition, Zrcher, Thome and Favrat (1999) found that the onset of dryout effect in theKattan-Thome-Favrat map was too strong compared to their new, more extensiveobservations for ammonia. They recommended reducing that the influence by one-half, so the value of q in expressions [12.4.8a] and [12.4.8b] should be replaced with q/2. To utilize this map, the following parameters are required: vapor quality (x), mass velocity(m& ), tube internal diameter (di), heat flux (q), liquid density (L), vapor density (G), liquid dynamic viscosity (L), vapor dynamic viscosity (G), surface tension (), and latent heat of vaporization (hLG), all in SI units. The local flow pattern is identified as follows: 1. Solve Eq. (12.4.16) iteratively with Eqs. (12.4.10), (12.4.13), (12.4.14) and (12.4.15); 2. Evaluate Eq. (12.4.12); 3. Evaluate Eqs. (12.4.6), (12.4.7), (12.4.8a), (12.4.8b) and (12.4.9); 4. Evaluate Eqs. (12.4.1), (12.4.2) or (12.4.3), (12.4.4), (12.4.5) and (12.4.11); 5. Compare these values to the given values of x and m& to identify the flow pattern. Note that Eq. (12.4.18) should be used in place of Eq. (12.4.1) and Eq. (12.4.17) should be usedin place of Eq. (12.4.11) to utilize the most updated version. The map is thus specific to thefluid properties, flow conditions (heat flux) and tube internal diameter input into theequations. The map can be programmed into any computer language, evaluating thetransition curves in incremental steps of 0.01 in vapor quality to obtain a tabular set ofthreshold boundary points, then displayed as a complete map with m& vs. x as coordinates.



Figure 12.9



Flow Pattern Map for n-Butane.

n-butane T sa t=60C D=19.89mm q=15kW/m2

0

50

100

150

200

250

300

350

400

0.0 0.2 0.4 0.6 0.8 1.0

Vapor quality

S

SW

I

A

MF



Flow Pattern Map for Propane.

Propane T sa t=0C D=15.75mm q=15kW/m2

0

50

100

150

200

250

300

350

400

0.0 0.2 0.4 0.6 0.8 1.0

Vapor quality

S

SW

I A

MF



Geometric eqs:

New eqs:

di

h

AGPG

AL PL

Pii

iiD

iLD d

PPdhh == ,

( )22 ,

,1

i

VVD

i

LLD

VL

dAA

dAA

AAAA

====

( ) ( ) ( )[ ]( ) ( )[ ] ( )( )[ ]

++

+

+=

22

3/13/13/1

strat

14112112001

11212

3122

=2

2cos15.0h stratLD

=2

2sinP stratiD

( )( ) ( ) ( )[ ]1

5.0

25.0118.11112.01

+

++=

L

VL

LVV mgxxxxx

&



Stratified-Wavy Transition:

Stratified Transition:

( )( ) ( )( )

( )

+

+

=

xxx

FrWex

hhx

gdAmqF

L

qF

LDLD

VLiVDwavy

197.0exp7550

1125121

16

22

5.0)(

)(2

2

5.0222

3 21

&

( ) ( )( ) x20x1x

gAA3.226m31

32LGLG

2GdLd

2

strat +

=&



Intermittent-Annular Transition (from setting Xtt = 0.34):

Mist Transition: Solve for

Bubbly Transition:

=WeFr

x

dgA7680m

LPh2 2

GLi2Gd

5.0

mist&

+

=

12914.0xG

L7/1

L

G75.1/1

1

IA

34.0

125.05.0875.0

1 ==

G

L

L

G

xx

X tt

minmist mm && =

( )( )

=

L25.0

id275.1

GLi25.1

L2LdGd

Px13164.0

gdAA256m

75.1/1

bubbly&



Other Equations:

L

i LWeFr

g d

=

2

2

LdPh A5.1

log2138.1

+=

+=

qqq

Fcrit

q

crit

q 2/8.640.646)(2/

2

1

023.1q

2/q8.18)q(Fcrit

2 +

=

( )[ ] 41VLLVV 2/1crit gh131.0q =



In new IJHMTPaper (2003):

Stratified=SStrat-Wavy=SWIntermittent=IAnnular=AMist=MF



THER

MO

CO

UP

LES

REFRIGERANT INLET

REFRIGERANT OUTLET

LIQUID REFRIGERANT

DUMMY TUBES

VAPOR REFRIGERANT

CROSS-SECTIONAL VIEW ALONG AXIAL LENGTH OF TEST SECTION

LIQUID REFRIGERANT

DROPLETS

LIQUID FILM

SATURATED NUCLEATE

BOILING (BUBBLY FLOW/

BUBBLE JET FLOW)

SLIDING BUBBLE

EVAPORATION(CHUGGING FLOW)

CONVECTIONTHROUGH

LIQUID FILM(SPRAY FLOW)

FLOW DISTRI-BUTING PLATE

COPPER TUBE BEARING HEAT SOURCE WATER WITH STAINLESS STEEL ROD POSITIONED CONCENTRICALLY WITHIN THE COPPER TUBE

COPPER TUBE BEARING HEAT SOURCE WATER WITH STAINLESS STEEL TUBE POSITIONED CONCENTRICALLY WITHIN THE COPPER TUBE

HEAT SOURCE WATER

THER

MO

CO

UP

LES

REFRIGERANT INLET

REFRIGERANT OUTLET

LIQUID REFRIGERANT

DUMMY TUBES

VAPOR REFRIGERANT

CROSS-SECTIONAL VIEW ALONG AXIAL LENGTH OF TEST SECTION

LIQUID REFRIGERANT

DROPLETS

LIQUID FILM

SATURATED NUCLEATE

BOILING (BUBBLY FLOW/

BUBBLE JET FLOW)

SLIDING BUBBLE

EVAPORATION(CHUGGING FLOW)

CONVECTIONTHROUGH

LIQUID FILM(SPRAY FLOW)

FLOW DISTRI-BUTING PLATE

COPPER TUBE BEARING HEAT SOURCE WATER WITH STAINLESS STEEL ROD POSITIONED CONCENTRICALLY WITHIN THE COPPER TUBE

COPPER TUBE BEARING HEAT SOURCE WATER WITH STAINLESS STEEL TUBE POSITIONED CONCENTRICALLY WITHIN THE COPPER TUBE

HEAT SOURCE WATER

OUTLET PRESSURE TAP

INLET PRESSURE

TAP



The coordinate axes are modified Baker parameters based on superficial liquid and gas velocities, uLs and uGs, corrected for fluid property variations.



Chisholm (1985) more recently has presented the following transition thresholds in terms of vapor quality for horizontal flows:

Stratified flow: [12.6.1]

Bubbly flow: [12.6.2]

Spray flow: [12.6.3]

)m2/(2

SS

S

B1R

xx1

=

)m2/(2

BB

B

B1R

xx1

=

)m2/(2

FF

F

B1R

xx1

=



In these equations, xS, xB, and xF are the transition qualities for the stratified, bubbly, and spray transition points, respectively. The other parameters are defined as:

[12.6.4]

[12.6.5]

[12.6.6]

and m is the exponent in a Blasius-type single-phase friction factor equation. The quantity FrL, is the Froude number for the total flow as liquid with the velocity based on the minimum cross-sectional area in the tube bundle normal to the flow direction. The reliability of general use of these methods for prediction of flow pattern transitions is not able to be qualified here.

( )( )

2/m

G

LF

2/1

G

LB

m2

S B;B;1Y22B

=

=+

=

m

G

L2LNFr59.03.1R

+=

m

G

L

G

L

LG dzdp/

dzdpY

=

=



Two-phase flow patterns have been too long ignored in heat transfer and pressure drop prediction methods. The Thome and coworker flow pattern maps for horizontal flows (adiabatic, evaporating and condensing) in plain tubes provide much more accuracy, more reliability and follow the trends in data better than earlier maps. Still remains a considerable amount of work to do on flow pattern transition boundary predictions for this and other applications, such as: effects of oil, microfins (some work done by Profs. Leibenberg and Meyer at Univ. of Pretoria), tube orientation, etc.



12.1: Determine the local flow pattern for each of the following qualities (0.05, 0.25, 0.50, 0.75 and 0.95) for a fluid flowing up a vertical tube of 22 mm internal diameter using Hewitt map. Flow rate of the fluid is 0.1 kg/s and physical properties are: liquid density = 1200 kg/m3, gas density = 20 kg/m3, surface tension = 0.012 N/m, liquid and vapor dynamic viscosities are 0.0003 Ns/m2 and 0.00001 Ns/m2.12.2: Determine the local flow pattern for each of the following qualities (0.05, 0.25, 0.50, 0.75 and 0.95) for a fluid flowing in a horizontal tube of 22 mm internal diameter using the Baker flow pattern map. The flow rate of the fluid is 0.1 kg/s. The fluid has the following physical properties: liquid density is 1200 kg/m3, gas density is 20 kg/m3, surface tension is 0.012 N/m and the liquid and vapor dynamic viscosities are 0.0003 Ns/m2 and 0.00001 Ns/m2.12.3: Determine the local flow pattern for each of the following qualities (0.05, 0.25, 0.50, 0.75 and 0.95) for a fluid flowing up a horizontal tube of 22 mm internal diameter using the Taitel-Dukler flow pattern map. The flow rate of the fluid is 0.05 kg/s. The fluid has the following physical properties: liquid density is 1000 kg/m3, gas density is 10 kg/m3, surface tension is 0.05 N/m and the liquid and vapordynamic viscosities are 0.0005 Ns/m2 and 0.00002 Ns/m2.



12.5: Determine the local flow pattern for the vapor quality of 0.50 for a fluid flowing up a horizontal tube of 22 mm internal diameter using the most updated version of the Thome and coworkers flow pattern map. The flow rate of the fluid is 0.05 kg/s. The fluid has the following physical properties: liquid density is 1000 kg/m3, gas density is 10 kg/m3, surface tension is 0.05 N/m and the liquid and vapordynamic viscosities are 0.0005 Ns/m2 and 0.00002 Ns/m2. Assume the flow is adiabatic.

Two Phase Flow Pattern and Flow Pattern

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