Two - phase Flow Patterns for Zeotropic Mixtures of Tetrafluoromethane/ethane in a Horizontal Smooth Tube Song Q.L., Gong M.Q., Wang H.C., etc. Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences, Beijing, China 24, July, 2019 Hartford, USA
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Two-phase Flow Patterns for Zeotropic Mixtures
of Tetrafluoromethane/ethane in a Horizontal
Smooth Tube
Song Q.L., Gong M.Q., Wang H.C., etc.
Key Laboratory of Cryogenics,
Technical Institute of Physics and Chemistry (TIPC),
Chinese Academy of Sciences, Beijing, China
24, July, 2019 Hartford, USA
Summary
Experiment apparatus
Adiabatic flow patterns
Condensation flow patterns
Introduction
Main Content
Introduction3/26
Aerospace
BioengineeringEnergy
Health care
A wide range of demand
Mixed-refrigerant Joule-Thomson
refrigeration (MJTR)
0
K
230
80
Single stage compression:
Higher pressure (30-50MPa)
Two/three stage cascade:
Complicated structure
Gas regenerative, Gas expansion:
Expensive, low efficiency
➢ Low pressure (2MPa)
➢ Low cost
➢ Simple structure
➢ non-moving parts at low
temperature parts
50 100 150 200 250 300 3500
5
10
15
20
25
He
Ne
N2
CH4
CF4
C2H
6
C3H
8
iC4H
10
iC5H
12ph=2.0 MPa
pl=0.1 MPa
h (
kJ/
mol)
T (K)
Mixed-refrigerants
Tetrafluoromethane (R14) and ethane
(R170) are the essential components in
the mixed-refrigerants.
➢ Pure fluids with different boiling points
➢ Zeotropic mixture
➢ Temperature relayTemperature relay
MJTR system
4/26Introduction
Two phase
Two phaseGas
From evaporator
High pressure Liquid To throttle
GasTo compressor
➢ Physical mechanism of two-phase heat transfer and pressure drop is closely related to flow patterns.
Heat exchangers
◆Aim of this work
A comprehensive presentation of the experimental studies on
➢ Adiabatic and condensation flow patterns for R14/R170 mixtures
5/26Introduction
Summary
Experiment apparatus
Adiabatic flow patterns
Condensation flow patterns
Introduction
Main Content
T T T TSight glass Sight glass
Heat flux
T
T T T T
C
T T
p
TT
Vacuum pump
Vacuum chamberCooling
loop 2
Cooling
loop 1 Heat
exchanger
Magnetic-
driven pump
Throttling
valve
Reservoir
DC Regulator
Preheater Sight glass Sight glass
Heat transfer section
p
Entrance effect
eliminated section
Experiment Apparatus
View glass - flow
pattern
Vacuum insulation
High speed camera
31
1 1
3
i ii
i i i
copper
T T
d dq
+
= +
−
− =
1
2
copper
Sq q
S=
Temperature distribution one-dimension Fourier Law
7/26
Experimental uncertainties
Parameters Instruments Range Uncertainties
T Pt100 80-300 K 0.1 K
p Pressure sensor 0-4 MPa 0.02%
G Mass flow meter 0–108 kg h-1 0.1%
◆Experiment conditions and uncertainties
Experimental conditions
Fluids Composition p(MPa) ∆Tbd(K) q(kW m-2) G(kg m-2 s-1) x D (mm)
R14/R170
0.19/0.81,
0.44/0.56,
0.63/0.37
0.8/0.2
1.5-2.5 3.6-30.7 8.4-42.2 100-350 0-1 4
8/26Experiment Apparatus
(b)
(c) (d)
(e)
(a)
Intermittent flow Transition flow
Wavy-annular flow Smooth-annular flow
Wavy-stratified flow
Intermittent: intermittent vapor slug with liquid bridge;
Transition: thick liquid layer in bottom with liquid waves can flap the tube top;
Wavy-annular: liquid film has discernable interfacial waves, can’t flap the tube top;
Smooth-annular: thin and fairly smooth liquid film along the entire tube perimeter;
Wavy-stratified: separate liquid and vapor layers with soft liquid waves.
9/26Experiment Apparatus
Summary
Experiment apparatus
Adiabatic flow patterns
Condensation flow patterns
Introduction
Main Content
0.0 0.2 0.4 0.6 0.8 1.0
100
150
200
250
300
350
p=2 MPa, R14:R170=0.632:0.368
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
G (
kg
m-2
s-1
)
x
(b)
◆Effect of mass flux
Adiabatic flow patterns
➢ Transition vapor qualities decrease with mass flux
➢ Wavy-stratified flow occur at lower mass flux
0.0 0.2 0.4 0.6 0.8 1.0
100
150
200
250
300
350
p=2 MPa, R14:R170=0.437:0.563
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
G (
kg
m-2
s-1
)
x
(a)
11/26
◆Effect of saturation pressure
➢ Transition vapor qualities increase with saturation pressure
0.0 0.2 0.4 0.6 0.8 1.0
1500
2000
2500
G=200 kg m-2 s
-1, R14:R170=0.193:0.807
Intermittent Transition Wavy-Annular
Smooth-Annular
P (
kP
a)
x
(a)
0.0 0.2 0.4 0.6 0.8 1.0
1500
2000
2500
G=200 kg m-2 s
-1, R14:R170=0.437:0.563
Intermittent Transition Wavy-Annular
Smooth-Annular
P (
kP
a)
x
(b)
pv
lv
lThermodynamic properties
12/26Adiabatic flow patterns
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
G=200 kg m-2 s
-1, p=1.5 MPa
Intermittent Transition Wavy-Annular
Smooth-Annular
X R
14
x
(a)
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
G=350 kg m-2 s
-1, p=2 MPa
Intermittent Transition Wavy-Annular
Smooth-Annular
X R
14
x
(b)
◆Effect of concentration
➢ Transition vapor qualities increase with the concentration of R14
Concentration Thermodynamic properties
13/26Adiabatic flow patterns
◆ Comparison with existing flow pattern maps
➢ Breber et al. and Tandon et al.: well predict the majority of
annular flow.
➢ Barbieri et al.: accurately predict the transition tendency
from intermittent flow to annular flow.
➢ Zhuang et al.: accurately predict the intermittent flow.
0.01 0.1 1 10
0.1
1
10Mist&Annular
Wavy-Stratified
Plug&Slug
Bubble
T
T
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
J v*
Xtt
Transition
T
(a)
0.01 0.1 1 10
0.01
0.1
1
10
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
J v
(1-)/
Mist
Annular&
Semi-Annular
Wavy
Slug
Plug
(b)
0.01 0.1 1 10
1E-3
0.01
0.1
1
10
Intermittent
Annular
FrL=3.75X
2.4
tt
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
Fr l
Xtt
(c)
0.01 0.1 1 101
10
IntermittentTransition
Wavy-Annular
Smooth-Annular
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
We*
Xtt
(d)
14/26Adiabatic flow patterns
◆ New flow pattern map
0.15 0.1
v lS Fr Bd Ca− −=
Inertia
force
Gravity
force
Surface
tension
Viscous
force
0.2
tt22 12.5S X −
1.71
tt21.45S X=
1.62
tt83.4S X=
1.52
tt360.6S X=
WS:
I to T:
T to WA:
WA to SA:
Song Q.L., Gong M.Q., et al. Int. J. Heat & Mass Transfer. 127, 2018, 910-924
0.01 0.1 1 10
10
100
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
S
Xtt
15/26Adiabatic flow patterns
Summary
Experiment apparatus
Adiabatic flow patterns
Condensation flow patterns
Introduction
Main Content
◆Effect of mass flux and saturation pressure
Condensation flow patterns
➢ Transition vapor qualities decrease with mass flux
➢ Transition vapor qualities increase with saturation pressure
0.0 0.2 0.4 0.6 0.8 1.0
1500
2000
2500
G=200 kg m-2 s
-1, q=26.0 kW m
-2
R14:R170=0.437:0.563
Intermittent Transition Wavy-Annular
Smooth-Annular
P (
kP
a)
x
(b)
0.0 0.2 0.4 0.6 0.8 1.0
100
150
200
250
300
350
p=2 MPa, q=26.0 kW m-2, R14:R170=0.437:0.563
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
G (
kg
m-2
s-1
)
x
(a)
17/26
◆Effect of heat flux
➢ Transition vapor qualities decrease with heat flux
➢ The effect of heat flux is more pronounced at higher R14 concentration (Fig. (b))
0.0 0.2 0.4 0.6 0.8 1.0
0
10
20
30
40
G=200 kg m-2 s
-1, p=2 MPa, R14:R170=0.193:0.807
Intermittent Transition Wavy-Annular
Smooth-Annular
q (
kW
m-2
)
x
(a)
0.0 0.2 0.4 0.6 0.8 1.0
0
10
20
30
40
Intermittent Transition Wavy-Annular
Smooth-Annular
q (
kW
m-2
)
x
G=200 kg m-2 s
-1, p=2 MPa, R14:R170=0.632:0.368
(b)
lv,R170 lv,R14H H
18/26Condensation flow patterns
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
G=200 kg m-2 s
-1, p=2 MPa, q=26.0 kW m
-2
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
X R
14
x
(a)
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
G=350 kg m-2 s
-1, p=2 MPa, q=26.0 kW m
-2
Intermittent Transition Wavy-Annular
Smooth-Annular
X R
14
x
(b)
◆Effect of concentration
➢ Transition vapor qualities increase first and then decrease
lv,R170 lv,R14H Hl,R14 l,R170 v,R14 v,R170,
Dynamic influence Thermodynamic influence
x x
19/26Condensation flow patterns
0.0 0.2 0.4 0.6 0.8 1.0
210
220
230
240
250
260
270
Subcooled liquid
p = 2 MPa
3l3
5
4
3v
1
Bubble point line
Dew point line
T (
K)
XR14
2
Superheated vapor
Two-phase
R170 R14
R14/R170 phase diagram at p = 2 MPaMass transfer influence
20/26Condensation flow patterns
G
Vapor mixture
Liquid mixture
Vapor-liquid interfaceDiffusion layer
Tube wallHeat fluxMass flux
YR14
XR14
R14 R170
◆Compared with adiabatic flow
➢ Condensation transition vapor qualities increase first and then decrease
➢ While adiabatic transition vapor qualities increase unchangeably
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
Adiabatic, G=350 kg m-2 s
-1, p=2 MPa
Intermittent Transition Wavy-Annular
Smooth-Annular
X R
14
x
(b)
0.0 0.2 0.4 0.6 0.8 1.0
0.0
0.2
0.4
0.6
0.8
1.0
Condensation, G=350 kg m-2 s
-1, p=2 MPa
Intermittent Transition Wavy-Annular
Smooth-Annular
X R
14
x
(a)
21/26Condensation flow patterns
◆ New flow pattern map
Nonequilibrium characteristics
Boiling number
Bo
Heat flux
q
Vapor and liquid
concentration difference
Y-X
Mass flux
G
Latent
heat Hlv
Mass transfer resistance of
zeotropic mixture
tttt 5 2 0.4
( , , ( ))1 8 10 1 ( )
Xf X Bo Y X
Bo Y X− =
+ + −
22/26Condensation flow patterns
◆ New flow pattern map
0.2
tt22 12.5 ( )S f X −
1.71
tt21.45 ( )S f X=
1.62
tt83.4 ( )S f X=
1.52
tt360.6 ( )S f X=
WS:
I to T:
T to WA:
WA to SA:
0.1 1 10
10
100
Intermittent Transition Wavy-Annular
Smooth-Annular Wavy-Stratified
S
f(Xtt, Bo, (Y-X))
tttt 5 2 0.4
( , , ( ))1 8 10 1 ( )
Xf X Bo Y X
Bo Y X− =
+ + −
23/26Condensation flow patterns
Summary
Experiment apparatus
Adiabatic flow patterns
Condensation flow patterns
Introduction
Main Content
➢ Flow visualization experiments of R14/R170 mixtures under
adiabatic and condensation conditions were presented.
➢ The effects of mass flux, saturation pressure, concentration
and heat flux on flow pattern transitions were analyzed.
➢ Both modified adiabatic and condensation flow pattern map