Simultaneous measurements of thickness and temperature profile in a wavy liquid film falling freely on a heating wall

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Energy Systems and Policy; (United States)

OSTI ID:5752932

Lyu, T; Mudawar, I ^[1]

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1. Boiling and Two-Phase Flow Lab., School of Mechanical Engineering, Purdue Univ., West Lafayette, IN (US)

This paper reports on a technique for measuring the thickness of liquid films that was developed and tested. The feasibility of this technique was demonstrated in stagnant liquid films as well as in liquid jets. A procedure for in-situ calibration of the thickness probe was developed, allowing the adaptation of the probe to measurements of wavy liquid films. The thickness probe was constructed from a platinum-rhodium wire that was stretched across the film. A constant DC current was supplied through the probe wire, and film thickness was determined from variations in the probe voltage drop resulting from the large differences in the electrical resistances of the wetted and unwetted segments of the wire. Unlike electrical admittance thickness probes, the new probe did not require dissolving an electrolyte in the liquid, making the new probe well suited to studies involving sensible heating of a film of pure dielectric liquid that is in direct contact with a current- carrying wall. Also presented is a composite probe that facilitated simultaneous measurements of temperature profile across a wavy liquid film and film thickness. Experimental results demonstrate a strong influence of waviness on liquid temperature in a film of deionized water falling freely on the outside wall of a vertical, electrically heated tube for film Reynolds numbers smaller than 10,000.

• OSTI ID: 5752932
• Journal Information: Energy Systems and Policy; (United States), Journal Name: Energy Systems and Policy; (United States) Vol. 14:4; ISSN 0090-8347; ISSN ESYPB
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
665520 -- Other Methods of Direct Energy Conversion-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
CURRENTS
DIELECTRIC MATERIALS
DIMENSIONS
DIRECT CURRENT
ELECTRIC CURRENTS
ELECTRODYNAMICS
ENERGY STORAGE
FILM CONDENSATION
FLUIDS
HEAT STORAGE
HYDROGEN COMPOUNDS
LIQUIDS
MATERIALS
MEASURING INSTRUMENTS
ON-LINE MEASUREMENT SYSTEMS
ON-LINE SYSTEMS
OXYGEN COMPOUNDS
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
PROBES
RHODIUM ALLOYS
SENSIBLE HEAT STORAGE
STORAGE
TEMPERATURE GRADIENTS
THICKNESS
THICKNESS GAGES
VAPOR CONDENSATION
WALLS
WATER
WAVE PROPAGATION
WIRES