Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

APPROACH TO HEAT TRANSFER MECHANISM BENEATH SINGLE BOILING BUBBLE WITH MEMS SENSOR

Get access (open in a dialog) DOI: 10.1615/IHTC13.p28.430
10 pages

Abstrakt

The MEMS technology have expanded capability in thermal sensing. We have employed the MEMS sensors including a trigger function and micro thin film thermocouples to study the complicated boiling heat transfer mechanism. First, local temperature variation beneath the boiling bubble triggered by small heating was measured on the sensor. Temperature trends can be brought into correspondence well with the bubble behavior taken by a synchronized high-speed video. It was found that a rapid temperature drop after bubble inception shows a formation and evaporation of the microlayer between the bubble and the heating wall, following temperature rise shows a dryout of the microlayer, and a momentary small temperature drop during a bubble departure process shows rewetting of the dry area. Based on the measurement, a state transition chart of the wall beneath the bubble can be drawn in a temporal and spatial domain. It was also found that electrolysis at a gap in heater electrode can trigger a reproducible single bubble generation with an extremely low input energy. Furthermore, by applying the temperature data as a boundary condition to a transient axisymmetric heat conduction simulation in the heating wall, local heat flux induced by the bubbling was derived. The approach method to the boiling heat transfer with the MEMS sensor has been established.