ISSN Online: 2377-424X
ISBN Print: 0-85295-345-3
International Heat Transfer Conference 10
THE ROLE OF THICKNESS AND THERMAL EFFUSIVITY IN POOL BOILING CHF IN HIGHLY-WETTING LIQUIDS
Abstrakt
Experimental studies have shown that the geometric
and thermophysical properties of the heater significantly
influence the critical heat flux (CHF). While the thermal
activity parameter δ√(ρcpλ) has been found to correlate
this variation very effectively, no physical explanation for
its success is as yet available. A conceptual CHF model,
emphasizing both the role of transient radial conduction
within the heater and the relationship between the heater
surface temperature and CHF, is proposed to account
for this dependence. A finite element analysis is used
to investigate the effect of heater and substrate thermal
properties on the temperature distribution at CHF.
The numerical results show that the thermal activity
parameter is associated with radial transient conduction
in the heater and that the presence of a substrate will
augment the critical heat flux on thin heaters with low
thermal activity values.