Gas-Liquid Horizontal Flow

José L.H. Faccini and Paulo A.B. SampaioInstituto de Engenharia Nuclear CNEN

Brazil

Jian SuNuclear Engineering Program, COPPEUniversidade Federal do Rio de Janeiro

Brasil

PASI 2007, August 2007, Mar del Plata, Argentina

Collaborators

Prof. Jen-Shih Chang, McMaster

Prof. Glenn Harvel, Univ Ontario Inst Tech

Tatiana Masala, AECL

Dr. Carlos Lamy, IEN/CNEN

Jurandyr Cunha de Souza, COPPE/UFRJ

Gas-liquid two-phase stratified and intermittent horizontal flow using

ultrasonic and high-speed visualization techniques

(Hewitt, Nuclear Eng. Design, 2005)

Two-Phase Flow – Steady State Operation

• Steady state operation of two-phase flow in pipes means that the flow rate of the fluids (gas and liquid) are constant;

• As a result, the conditions at any point in the pipe remains constant: the flow pattern, average void fraction, average pressure drop and average local flow rates do not vary with time;

• two flow seldom is a truly steady state flow and averaging values are used over a time period characteristic of the flow pattern.

Gas-Liquid Vertical Flow

Gas-Liquid Horizontal Flow

Flow Regime Map

Definition of Basic Parameters

T

L

T

G

A

A-1 ,

A

A

T

LsLs

T

GsGs A

Qu ,

A

Qu

1

uu ,

uu Ls

LGs

G

T

Ls

T

Gs

Q

Q-1 ,

Q

Q

Void fraction and liquid holdup

Gas and liquid superficial velocities

Gas and liquid (phase) velocities

Volumetric fraction or nonslip holdup

Experimental Techniques

Technique InterferingSteady

State

Slow transi

ent

Fast Transient

Flow Regime

Local Void fraction

Averaged

Void

fraction

Void fracti

on distributio

n

Phase Velocity

Conductance Yes Yes Yes Yes No Yes No Limited Yes

Capacitance No Yes Yes Yes Yes No Yes Limited Yes

Opticaltechniques

Yes Yes Yes Yes Yes Yes Yes Limited Yes

Gamma ray No Yes Yes NeedStrongSource

Yes No Yes Limited Yes

X-ray No Yes Yes Yes Yes No Yes Yes Yes

NeutronRadiography

No Yes Yes No Yes No Yes Yes Yes

Ultrasonic No Yes Yes Yes Yes Limited Yes Yes Yes

Masala (2004)

Gas-Liquid Horizontal Flow Rig

Experimental flow regimes

Experimental Setup

Experimental Setup

Doppler Flowmeter

Doppler ultrasonic flowmeters operate on the Doppler effect, whereby the transmitted frequency is altered linearly by being reflected from particles and bubbles in the fluid. The net result is a frequency shift between transmitter and receiver frequencies that can be directly related to the flow rate.

Transit Time/Transmission Technique

Pulse-Echo Technique

Chang et al. (1982) e Morala e Chang (1986).

Ultrasonic Techniques

Dia:12/11/05 Hora:18:01:35

Valores Observações3,949E-5Arquivo escoamento_ST_000.txt3,924E-5Arquivo escoamento_ST_001.txt3,928E-5Arquivo escoamento_ST_002.txt7,444E-5Arquivo escoamento_ST_003.txt3,932E-5Arquivo escoamento_ST_004.txt3,994E-5Arquivo escoamento_ST_005.txt

Ultrasonic Techiques

Liquid level measurement calibration

Liquid thickness in stratified flow

Gas-liquid horizontal flow setup (McMaster)

Ultrasonic System for Two-Phase Flow

CS12100 Card

WinspectSoftware

Motor ControllerDMC 1800

Multiplexer

…

1

42

UG

3

UL

1 2 3 4

Transducers

Transducers

PC

Masala (2004), Masala, Harvel, Su, Chang (2007)

Slug flow

Slug Flow at ULs=0.072 m/s & UGs=1.92 m/s

0

0.4

0.8

1.2

1.6

2

0 0.4 0.8 1.2 1.6 2 2.4 2.8 3.2

Time(sec)

Liqu

id L

evel

(cm

)

0

1

Transducer # 4

Transducer #3

Top of the Tube

Bottom of the tube

Plug flow

Plug Flow at 6ms

0

0.5

1

1.5

2

2.5

0 0.5 1 1.5 2 2.5 3 3.5

Time(s)

Dis

tan

ce

(c

m)

transducer 4

transducer 2

Visualization System

Smooth Stratified Flow

Wavy Stratified Flow

Plug Flow

Slug Flow

An elongated bubble

Plug front and tail velocity – Ultrasonic measurement

Bubble nose and tail velocity - Visualization

Acknowledgement

CNPq, FAPERJ, CAPES of Brazil

PASI 2007 Organizers

Thank you for attention.