2007 Volume 24 Issue 1 Pages 71-
Transparent heating surface with multiple arrays of 88 thin film temperature sensors and mini-heaters is developed for the clarification of boiling heat transfer mechanisms under microgravity conditions, where the relation between local heat transfer coefficients and behaviors of liquid microlayer underneath attached vapor bubbles is investigated. Local surface temperature is controlled to keep constant by the feedback circuits, and a simple boundary condition on the heat transfer surface is realized. Preliminary boiling experiments on ground are conducted using FC72 as a test fluid at pressure P= 0.1 MPa, liquid subcoolingΔ Tsub = 10.8 K and a constant surface temperature 58.8℃. The local heat flux change characterized by the heat transfer enhancement due to the microlayer evaporation and the deterioration by the extending dry patches is detected corresponding to the observed liquid-vapor behaviors underneath a coalesced bubble.