Abstract:
An experimental investigation on heat transfer characteristics of an
evaporator of a two-phase closed-looped thermosyphon is carried out in this study.
Experiments are conducted using three different evaporator surfaces, namely Pin
Finned Surface (PFS), Rectangular Finned Surface (RFS) and Plain Surface (PS)
with three different working fluids Acetone, Ethanol and Methanol. Bubble
frequency and bubble density per unit area has been estimated. A fan of 40 W is
used to know its effect on heat flux. Ethanol has shown the highest heat flux of 73
kW/m2 and 110 kW/m2 without and with fan respectively and (7-20) % higher than
other working fluids. Heat flux can be increased to (20-35) % with the condensing
fan. It is found that Rectangular Finned Surface (RFS) can transfer (15-30) % more
heat than that of other surfaces among all the working fluids. Heat flux increases
with bubble frequency and bubble density per unit area. The heat flux data have
been compared with an existing correlation and found ±30% agreement.
