Abstract:
Pulsating heat pipe is a two-phase heat transfer device that uses pulsating motion to
transfer heat from a source and passively move it to a condenser or radiator. In the recent
past, many researches have been carried out on Pulsating Heat Pipes (PHPs) to enhance
heat transfer through passive two-phase heat transfer mechanism. Although a complete
theoretical understanding of operational characteristics of this device is not yet achieved,
there are many emerging applications, ranging from electronics thermal management to
compact heat exchangers. For a better theoretical understanding, it is vital to generate
experimental data under various operating boundary conditions. In this background, this
study aims for thermal analysis of a closed loop pulsating heat pipe based on heat input,
inclination, fill ratio. So, a closed loop pulsating heat pipe is designed and fabricated
with Aluminium. This closed loop Aluminium PHP with ammonia as working fluid is
experimentally investigated for variable varying inclination and fill ratios. The
experimental apparatus consists of a 8.862m long 3mm inner diameter closed loop
Aluminum pipe meandering back and forth into an electrically heated block of
Aluminum. One end of the PHPs is inserted inside the heater and the other end of it is
placed in air. Heat transfer characteristics of PHPs are determined experimentally, based
on the heat transfer principles. Response curves in terms of heat transfer rate, heat
transfer coefficient and thermal resistance are obtained for different inclinations and
liquid ammonia fill ratios. The overall heat transfer coefficient and thermal resistance of
the system is determined to show the heat transfer capability of the PHP. The results
show that, the performance of the heat pipe varies substantially for different inclinations
and fill ratios.
