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Title: Heat Transfer Coefficient Measurement Study of Several Film Boiling Modes in Subcooled He II

Abstract

This study was carried out for more detailed information about film boiling heat transfer in subcooled superfluid helium (He II). A number of film boiling modes were experimentally investigated in a wide range of the pressure from the atmospheric pressure down to the saturated vapor pressure. A thin stainless steel foil heater was used to cause film boiling and as a temperature sensor to measure the heater surface temperature. The results drawn from the heat transfer coefficient measurement give a support to the previous conclusion reached by visualization and pressure measurement studies that two film boiling modes appear in subcooled He II, that is the strongly subcooled film boiling mode and the weakly subcooled film boiling mode. It is, however, found that the dependence of the heat transfer coefficient on pressure was much different from those of conventional fluids. The heat transfer coefficient weakly decrease with the pressure in the weakly subcooled film boiling, and on the other hand it is almost independent of the pressure in the strongly film boiling. The peak of heat transfer coefficient appears at about 8 kPa in the transition region between the weakly subcooled and the noisy film boiling modes.

Authors:
; ;  [1];  [2]
  1. Graduate School of Systems and Information Engineering, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8573 (Japan)
  2. Cryogenics Science Center, Applied Research Laboratory, High energy Accelerator Research Organization, Oho 1-1, Tsukuba 305-0801 (Japan)
Publication Date:
OSTI Identifier:
20800218
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 823; Journal Issue: 1; Conference: Cryogenic engineering conference, Keystone, CO (United States), 29 Aug - 2 Sep 2005; Other Information: DOI: 10.1063/1.2202441; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; FILM BOILING; FOILS; HEAT TRANSFER; HELIUM 4; PRESSURE MEASUREMENT; STAINLESS STEELS; SUBCOOLING; SUPERFLUIDITY; VAPOR PRESSURE

Citation Formats

Takada, S., Murakami, M., Nozawa, M., and Kimura, N. Heat Transfer Coefficient Measurement Study of Several Film Boiling Modes in Subcooled He II. United States: N. p., 2006. Web. doi:10.1063/1.2202441.
Takada, S., Murakami, M., Nozawa, M., & Kimura, N. Heat Transfer Coefficient Measurement Study of Several Film Boiling Modes in Subcooled He II. United States. doi:10.1063/1.2202441.
Takada, S., Murakami, M., Nozawa, M., and Kimura, N. Thu . "Heat Transfer Coefficient Measurement Study of Several Film Boiling Modes in Subcooled He II". United States. doi:10.1063/1.2202441.
@article{osti_20800218,
title = {Heat Transfer Coefficient Measurement Study of Several Film Boiling Modes in Subcooled He II},
author = {Takada, S. and Murakami, M. and Nozawa, M. and Kimura, N.},
abstractNote = {This study was carried out for more detailed information about film boiling heat transfer in subcooled superfluid helium (He II). A number of film boiling modes were experimentally investigated in a wide range of the pressure from the atmospheric pressure down to the saturated vapor pressure. A thin stainless steel foil heater was used to cause film boiling and as a temperature sensor to measure the heater surface temperature. The results drawn from the heat transfer coefficient measurement give a support to the previous conclusion reached by visualization and pressure measurement studies that two film boiling modes appear in subcooled He II, that is the strongly subcooled film boiling mode and the weakly subcooled film boiling mode. It is, however, found that the dependence of the heat transfer coefficient on pressure was much different from those of conventional fluids. The heat transfer coefficient weakly decrease with the pressure in the weakly subcooled film boiling, and on the other hand it is almost independent of the pressure in the strongly film boiling. The peak of heat transfer coefficient appears at about 8 kPa in the transition region between the weakly subcooled and the noisy film boiling modes.},
doi = {10.1063/1.2202441},
journal = {AIP Conference Proceedings},
number = 1,
volume = 823,
place = {United States},
year = {Thu Apr 27 00:00:00 EDT 2006},
month = {Thu Apr 27 00:00:00 EDT 2006}
}
  • Film boiling modes in both subcooled and saturated superfluid helium (He II) were experimentally investigated. The visual observation and the transient pressure and temperature measurements were performed to extract some characteristics of each boiling mode. The classification of all four film boiling modes, strongly subcooled and weakly subcooled modes in subcooled He II (He IIp) and noisy and silent film boiling modes in saturated He II (He IIs), was drawn on the boiling mode map. It was found from the heater temperature measurement that the boiling heat transfer is enhanced in the weakly subcooled mode compared with in the stronglymore » subcooled mode. In the weakly subcooled mode, the vapor behavior is much activated by the instability in vapor-liquid interface. The boundary region between the strongly and the weakly subcooled modes becomes thick as the rise of He II temperature or the increase of the heat flux. The noisy film boiling does not occur at the pressure above 9 kPa, though it appears at the pressure above p{lambda}. It is found that in the region adjacent to the lambda line He I film boiling mode occurs even in He II.« less
  • A rigorous numerical solution of a theoretical model based on laminar boundary layer theory for pool film boiling heat transfer from a horizontal cylinder including the contributions of liquid subcooling and radiation from the cylinder was obtained. The numerical solution predicted accurately the experimental results of pool film boiling heat transfer from a horizontal cylinder in water with high radiation emissivity for a wide range of liquid subcooling in the range of nondimensional cylinder diameters around 1.3, where the numerical solution was applicable to the pool film boiling heat transfer from a cylinder with negligible radiation emissivity. An approximate analyticalmore » solution for the theoretical model was also derived. It was given by the sum of the pool film boiling heat transfer coefficient if there were no radiation and the radiation heat transfer coefficient for parallel plates multiplied by a nondimensional radiation parameter similar to the expression for saturated pool film boiling given by Bromley. The approximate analytical solution agreed well with the rigorous numerical solution for various liquids of widely different physical properties under wide ranges of conditions.« less
  • He II film boiling is of both academic and applied interests. However, the information about film boiling heat transfer in He II is still insufficient and needs further investigation. In the present study, a thin stainless steel foil heater (10 {mu} m thick) is used to cause boiling in He II. The heater temperature is measured to evaluate the heat transfer performance of He II film boiling under different thermal conditions. The pressure and the heater surface temperature oscillations induced by the film boiling are also simultaneously measured. The heat transfer coefficients of three kinds of boiling states: noisy filmmore » boiling, transition boiling and silent film boiling, are obtained in the present study.« less
  • The empirical correlations for subcooled film-boiling heat transfer during a reactivity initiated accident in light water reactors are derived from inverse heat conduction calculations using the cladding surface temperatures measured in in-reactor experiments. The experimental data for cold startup conditions (subcoolings of about 10 to 80 K and coolant velocities of about 0 to 2 m/s at atmospheric pressure) and hot standby conditions (subcooling of about 10 to 40 K, system pressures of 7.2 and 16 MPa, and system temperatures of 550 and 580 K) are used for this investigation. The present correlations are compared with existing correlations from ex-reactormore » experiments. The results of transient fuel behavior calculations with a computer code that included the present correlations are in good agreement with the corresponding measured data from the experiments.« less