Void Fraction and Vapor and Liquid Temperatures: Local Measurements in Two-Phase Flow Using a Microthermocouple

Abstract

A technique is described which enables the detection of the phase (liquid or vapor) in steam-water two-phase flow and the temperature measurement of each phase, using the hot junction of a microthermocouple. The signals are processed with a multichannel analyzer in order to obtain the amplitude histograms of the temperature. Significant results are obtained in pool boiling, forced convection subcooled boiling, and flashing flow of water.

Two-phase flow structure of sheet cavitation

“…Different types of local probe have been developed for determining the phase density function in gas-liquid flows. Among these are impedance measurements ͑Nassos and Bankoff; 12 Serizawa et al 13 ͒, the capacitive method ͑Gunn and Al-Doori 14 ͒, hot wire technique ͑Bremhorst and Gilmore 15 ͒, temperature measurements ͑Delhaye et al 16 ͒ and optical techniques ͑Abuaf et al, 17 Cartellier and Achard 18 ͒. In the recent past, new nonintrusive techniques have appeared: X-ray scattering techniques ͑Han and Wesser 19 ͒, nuclear magnetic resonance ͑Javelot et al 20 ͒, and the grating velocimeter-granulometer ͑Cartellier 21 ͒.…”

A study of local heat transfer mechanisms along the entire boiling curve by means of microsensors

“…Van Stralen and Sluyter [14] used a commercially available sheathed TC of 0.25 mm diameter to measure temperature fluctuations associated with steam bubbles above a heated wire. Delhaye et al [15] developed a bare wire TC with a wire diameter 20 µm, but not of the stretched form type in order to avoid bubble deflection at the horizontal wire. They performed a statistical analysis of the signals.…”

Axial developments of interfacial area and void concentration profiles in subcooled boiling flow of water

“…In subcooled boiling flow, most of previous works have dealt understandably with the measurements of gross effects rather than local effects. The earliest experiment to attempt the measurement of local void fraction was by Delhaye et al [3]. They developed a fast micro-thermocouple that could enable the detection of the gas or liquid phase, and measured the local void fraction and temperatures of liquid and gas in steam-water flow.…”