Y. Wang et K. Vafai, An experimental investigation of the transient characteristics on a flat-plate heat pipe during startup and shutdown operations, J HEAT TRAN, 122(3), 2000, pp. 525-535
This work presents an experimental investigation of the thermal performance
of a flat-plate heat pipe during startup and shutdown operations. Using th
e analytical model developed in a previously study, analytical and experime
ntal results on the effect of input power and cooling heat transfer coeffic
ient on the thermal performance of the heat pipe are presented and discusse
d. The results indicate that the wick in the evaporator section provides th
e largest resistance to the heat transfer process followed by the wick in t
he condenser section. It is found that the heat transfer coefficient has an
insignificant effect on the maximum temperature difference across the heat
pipe where this difference refers to the maximum difference on the outside
surfaces of the flat-plate heat pipe. However, as expected, the input heat
flux has a substantial effect on the temperature rise where the temperatur
e rise refers to the temperature increase on the outside surface of the hea
t pipe. It is found that the temperature difference across the heat pipe de
pends mainly on the input power. The heat transfer coefficient strongly aff
ects the item it takes to reach steady state while input power has a substa
ntially smaller effect. Empirical correlations for the maximum temperature
rise, the maximum temperature difference and the time constants are obtaine
d. The experimental results are compared with the analytical results and ar
e found to be in very good agreement.