Performance assessment of planar and non-planar cryogenic pulsating heat pipe with novel condenser

Abstract

Pulsating heat pipe (PHP) is gaining popularity as a viable solution for thermal conductive links associated with a cryogenic cooling system. A competitive commercial environment requires PHP with a more compact configuration, high heat load removal capacity, and free of orientation dependency. Making orientation-free PHP, a planar PHP (2D layout), requires a large number of turns, increasing the overall size of the PHP device. A PHP with a non-planar (3D layout) layout is capable of accommodating a large number of turns in a short area to tackle both compactness and orientation-dependent issues. The present paper focuses on a comparative thermal performance assessment of planar and non-planar configurations of cryogenic PHP by developing a novel cylindrical shell-type condenser (CSTC). Liquid nitrogen is used as a working fluid. Two separate test setups are developed with 2D Four-Turn PHP (2D FT-PHP) and 3D Four-Turn PHP (3D FT-PHP) with a novel CSTC. The condenser, adiabatic, and evaporator lengths of PHP are kept as 60 mm, 120 mm, and 50 mm, respectively. The thermal performance is assessed by varying Filling Ratio (FR) (38−95 %) and heat load (1 W–130 W) with an evaporator at the bottom position. It is observed that, for a particular heat load, a 3D FT-PHP performed better than a 2D FT-PHP, irrespective of FR. The anti-dry-out ability of 3D FT-PHP is observed to be superior to 2D FT-PHP at a low FR. The frequency analysis results with Wavelet transform show that the working fluid oscillates with a more dominant frequency in 3D FT-PHP than in 2D FT-PHP configuration.