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Multiphase Science and Technology

A Quarterly

ISSN for PRINT: 0276-1459

Institutional price:	$694.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2007, Volume19

118 pages

DOI: 10.1615/MultScienTechn.v19.i2

Issue price - $193.00

JET IMPINGEMENT BOILING IN HOT SURFACES WELL ABOVE THE LIMITING TEMPERATURE FOR SOLID-LIQUID CONTACT

M. A. Islam
Dept. of Mechanical Engineering, Saga University, 1 Honjo Saga City, Saga 840-8502, Japan

Masanori Monde
Department of Mechanical Engineering, Saga University, 1 Honjo Saga City, Saga 840-8502, Japan

P. L. Woodfield
Dept. of Mechanical Engineering, Saga University, 1 Honjo Saga City, Saga 840-8502, Japan

Yuichi Mitsutake
Department of Mechanical Engineering, Saga University, 1 Honjo Saga City, Saga 840-8502, Japan

A. K. Mozumder
Dept. of Mechanical Engineering, Saga University, 1 Honjo Saga City, Saga 840-8502, Japan

ABSTRACT

Jet impingement boiling phenomena in hot surfaces were investigated by means of temperature measurements and video records. A 2-mm water jet of 5−80 K subcooling and of 3−15 m/s velocity was impinged on the flat surface of a cylindrical steel or brass block that was preheated to 400−600°C. During the quench, the transient temperature responses of 16 thermocouples embedded in two depths beneath the surface were recorded to estimate surface temperature by an inverse heat conduction technique. A high-speed video camera was also employed to capture images of boiling and flow phenomena. Sometimes the flow became explosive/noisy and sometimes very calm and quiet. Different flow patterns, as identified from video images, resulted from the interactions between the jet and vapor bubbles formed at/near the impinging surface. The flow patterns are found to be dependent on the block material and its surface temperature. It is also found that for a certain period of time, the surface temperature (T_ω) remains well above the thermodynamic limiting temperature (T_max) for solid-liquid contact. The cooling curves at the center of the impinging surface for different experimental conditions are explained in relation to the limiting temperature. A theoretical approach to elucidate the early-stage phenomena is also outlined in this study.