An experimental study of subcooled film boiling on a vertical surface - Hydrodynamic aspects

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2911242· OSTI ID:5022489

Vijaykumar, R; Dhir, V K ^[1]

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1. Univ. of California, Los Angeles (United States)

The aim of the present study is: (1) To determine the physical characteristics of the interfacial waves for different wall superheats and liquid subcoolings. (2) To determine the velocity field adjacent to the interface at different locations along the interface. Interface and liquid velocities near the leading edge of a vertical wall 6.3 cm wide and 10.3 cm high were measured during subcooled film boiling of water at 1 atm pressure. The interface and liquid velocities in the boundary layer adjacent to the interface were measured using the hydrogen bubble flow visualization method. Photographs taken from the front and side showed the existence of a finite vapor layer at the leading edge and the existence of ripples and large-amplitude waves (bulges) on the interface. The bulges and ripples did not slide on the interface but moved in unison with the interface. The wave amplitude and wavelength were also measured. For a given subcooling and wall superheat, the amplitude, the interfacial velocity, and the wavelength were found to attain an equilibrium value several millimeters downstream of the leading edge. The waves were highly nonlinear and the interface velocities, which are found to be governed by the wave amplitude, were much larger than those predicted from the smooth interface, laminar flow theory. Streamlines in the liquid were found to expand into the wave valleys. At the wave peaks the streamlines appeared to be clustered together and the measured interface velocity gradients were high. The overall picture is one of expansion in the wave valleys and contraction (of flow) at the wave peaks. The flow field in turn is found to affect the liquid side heat transfer in subcooled film boiling significantly.

• OSTI ID: 5022489
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 114:1; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BENCH-SCALE EXPERIMENTS
BOILING
FILM BOILING
FLUID MECHANICS
HYDRODYNAMICS
INTERFACES
MECHANICS
ORIENTATION
PHASE TRANSFORMATIONS
PLATES
SUBCOOLED BOILING
WAVE PROPAGATION