A novel investigation on single-loop pulsating heat pipe filling with hybrid nanofluids: numerical and experimental

Abstract

Pulsating heat pipes (PHPs) employ to multiphase heat transfer between condensers and evaporators. The efficacy of PHP is predominantly contingent upon the thermos-physical property exhibited by its working fluid. The exergy analysis of evaporator, adiabatic and condenser system were performed to evaluate the efficiency and sustainability of energy conversion processes, it was also seen that exergy loss of condenser was 1.01% higher than evaporator. Further, 2-D numerical simulation of a cryogenic pulsating heat pipe (CPHP) was conducted and also numerical and experimental simulation was conducted, where simulation results agreed with experimental results with 10% similarity. The simulation employs the volume of fluid (VOF) model to capture the dynamics of two-phase liquid–vapor flow within the CPHP employing liquid acetone – Al₂O₃ as the working fluid. The diameter of the single turn is systematically varied, ranging from 1 mm to 2.5 mm, while maintaining the filling ratio (FR) within the range of 25% to 75%. The evaporator temperature is adjusted within the span of 85 K to 115 K. The PHP exhibited best thermal performance at inner diameter of 2 mm among (1, 1.5, 2, 2.5 mm) and filling ratio of 55% among (25%, 45%, 55%, 65% and 75%).