G. Monni, M. De Salve, B. Panella Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino...
-
Upload
kelley-white -
Category
Documents
-
view
219 -
download
0
Transcript of G. Monni, M. De Salve, B. Panella Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino...
TWO-PHASE ANNULAR FLOW IN A VERTICALLY MOUNTED
VENTURI FLOW METERG. Monni, M. De Salve, B. Panella
Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 [email protected]
HEFAT201410th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics14 – 16 July 2014Orlando, Florida
Context Objective Experimental Facility and Test Matrix Venturi Flow Meter (VFM) Experimental Results VFM Modeling Two-Phase Flow Mass Flow Rates Estimation Conclusions
Outline
2HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Experimental Facility for thermal-hydraulic simulation of innovative small and medium size PWR SPES3
Measurement of the mixture mass flow rate instruments and methodologies to evaluate different two- phase flow parameters need to be developed
Typically a set of instruments (Spool Piece - SP) must be installed: each instrument of the SP has to be sensitive to the different properties of the flow (momentum, velocity, density, void fraction, etc..)
Different number of instruments can be coupled in a SP
Context
3HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Analysis of the response of a Venturi Flow Meter (VFM) in two-phase flow
To develop a methodology for the signals interpretation and a “model of the instrument” for the phases mass flow rate estimation
The SP is tested in a vertical test section for air-water flow at very high void fraction
The model and the results are presented and discussed
Objectives
4HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Test Section
Vertical Test section:
Di = 80 mm De = 90 mm
L ≈ 4 m
VFM placed at L/D~ 30 from the inlet
Test section equipped with pressure transducers
thermocouple and
Quick- Closing Valves
5HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Experimental Matrix
14 16 18 200.96
0.97
0.98
0.99
1
Jg [m/s]
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
14 16 18 200.96
0.97
0.98
0.99
1
Jg [m/s]
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
Fluids:
◦ Demineralized water
◦ Air Jg : 14 - 18 m/s Jl : 0.0008 – 0.005 m/s x : 0.78 – 0.96 α : 0.97 - 1 p : ≈ 1 bar T : 20 – 25 °C
Very high void fraction corresponding to annular and mist-annular flow
6HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Venturi Flow Meter (VFM)
Type Bi-Directional Fluid water
D1 80 mm θconv.= θdiv. 21°
D2 40 mm Lup-downstream 628 mm
β 0.5 - Ltot 340 mm
Estimation of the fluid flow rate from the pressure drop across a pipe restriction
This is perhaps the most commonly used flow measurement technique in industrial applications (low p, economic, no moving Δpart, etc…)
Characteristic parameters of the present tests VFM (designed by Polito)
7HEFAT2014 14 – 16 July 2014 - Orlando, Florida
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.E+00 2.E+04 4.E+04 6.E+04 8.E+04 1.E+05
Cd
Re
YFp
ACQ ad
5.0
421
2
The air single-phase flow discharge coefficient is evaluated, based on the
experimental data (Y and Fa ≈ 1)
VFM Experimental Results: Single-Phase
241A
YFCK aTP
Calibration parameters: a=1.5054 b=-0.0510
bd aC Re
8HEFAT2014 14 – 16 July 2014 - Orlando, Florida
The two-phase flow pressure drop and losses analyzed at different
superficial velocities of the two phases theoretical/experimental modeling
ΔpV Δpirr
14 15 16 17 18 198
10
12
14
16
18
20
22
24
Jg [m/s]
p TP
-irr [
mba
r]
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
14 15 16 17 18 198
10
12
14
16
18
20
22
24
Jg [m/s]
p V
irr [
mbar]
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
14 15 16 17 18 1920
25
30
35
40
45
Jg [m/s]
p TP
-V [
mba
r]
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
VFM Experimental Results: Two-Phase (I)
9HEFAT2014 14 – 16 July 2014 - Orlando, Florida
The measured ΔpV increases of about 10%, if compared to the single-phase flow, the ΔpV –irr increases from about 20% to 100%
depending on the liquid flow rateΔpV –irr high sensitivity to the liquid flow rate
ΔpTP-irr = f(x,Jg,Jl)10HEFAT2014 14 – 16 July 2014 - Orlando, Florida
0.75 0.8 0.85 0.9 0.95 1
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
x
(p TP
p g) irr
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
(Δp T
P /
Δp g
) irr
14 15 16 17 18 191
1.01
1.02
1.03
1.04
1.05
1.06
1.07
1.08
Jg [m/s]
p V
-TP /
p V
-g
Jl = 0.0008 m/s
Jl = 0.0017 m/s
Jl = 0.0028 m/s
Jl = 0.0033 m/s
Jl = 0.0039 m/s
Jl = 0.0050 m/s
VFM Experimental Results: Two-Phase (II)
11
VFM Experimental Results: Two-Phase (III)
0.08 0.09 0.1 0.11 0.12 0.1320
25
30
35
40
45
Wt [kg/s]
p V
[m
bar]
12
VFM Experimental Results: Two-Phase (IV)
0.08 0.09 0.1 0.11 0.12 0.1310
20
30
40
50
Wt [kg/s]
p
[mba
r]
V: in-throat
Irr: in-out
25 30 35 40 455
10
15
20
25
pV
[mbar]
p irr
[m
bar]
single-phase (air)
two-phase
VFM pressure drop and VFM irreversible pressure loss vs. total mass flow rate
VFM irreversible pressure loss vs. VFM pressure drop
0 0.002 0.004 0.006 0.008 0.011
1.02
1.04
1.06
1.08
1.1
1.12
exp
2 g
2M
2C
2mod
2exp
VFM Modeling: ΔpV
18.72mod
5.0
2 1
l
g
x
x
A Two-Phase flow Multiplier correlation has been developed, based on
experimental data and compared with classical
correlations. The new correlation predicts ΔpV with an error lower than 5%
22 1 CC
g
22 51 M
g
g
TPg p
p
2
13HEFAT2014 14 – 16 July 2014 - Orlando, Florida
10 14 18 22 2610
14
18
22
26
pirr
[mbar]
p irr
[m
bar]
+5%
-5%
VFM Modeling: ΔpVirr
A new correlation has been developed, based on experimental data.
The proposed correlation describes the irreversible pressure loss change as a function of the superficial
velocities of the two phases and of the ratio between the liquid and the gas superficial
velocities, highlighting the effect of the dispersed phase.
The new correlation predicts ΔpVirr with an error lower
than 5%
4132 kJJJkp k
glkggirrTP
k1 = 0.2096 - k2 = 2 - k3 = 0.13 - k4= -2.9786
14HEFAT2014 14 – 16 July 2014 - Orlando, Florida
5.0
2 1
l
g
x
x
Mass Flow Rate Estimation
The Model consists of a set of equations able to derive the mass flow rate of the phases from the instruments signals of:◦Venturi flow meter◦Pressure transducers◦Thermocouples
• An iterative approach is used to estimate the flow parameters of the two phases
ΔpV
WTP
T, PΔpirr
gl
gl
xguess
gVTPV pp )18.7(
4132 kJJJkp k
glkggirr
15HEFAT2014 14 – 16 July 2014 - Orlando, Florida
With the proposed approach the flow quality of the mixture can be evaluated with an accuracy of 5% and the mass flow rate of air and water can be
estimated with a minimum accuracy of 2% and 30% respectively
0 0.01 0.02 0.030
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Wl,exp
[kg/s]
Wl,e
st [
kg/s
]
+30%
-20%
+20%
-30%
0.08 0.09 0.1 0.110.08
0.085
0.09
0.095
0.1
0.105
0.11
Wg,exp
[kg/s]
Wg,
est [
kg/s
]
-2%
+2%
Results
The standard deviations are 1%, 10 % and 2 % for the air flow rate, the liquid flow rate and the quality respectively
16HEFAT2014 14 – 16 July 2014 - Orlando, Florida
In the present research work, the experimental investigation of a vertical upward annular two-phase flow by a Venturi Flow Meter (VFM) has been performed.
The dependence of the pressure drops, evaluated between the VFM inlet and throat sections and between the inlet and outlet sections, on the characteristic flow parameters (flow velocities, quality and void fraction) have been analyzed and discussed.
Correlations describing the relation between velocities and VFM pressure drops have been proposed for the two pressure drops components. For both correlations the error is lower than 5%.
Conclusions
17HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Conclusions The analysis of the VFM irreversible pressure losses shows
that important information can be derived concerning the effect of the liquid dispersed phase
The proposed correlation describes the irreversible pressure loss change as a function of the flow rate of the two-phases, highlighting the effect of the dispersed phase.
A model for the estimation of the mass flow rate of the two phases from the instrument signals has been developed: it allows the evaluation of the flow quality with an accuracy of 5% and the estimation of the mass flow rate of air and water with an error of 1% and 10% respectively
18HEFAT2014 14 – 16 July 2014 - Orlando, Florida
Thank you for your kind attention
19HEFAT2014 14 – 16 July 2014 - Orlando, Florida