Experimental investigations on two-turn cryogenic pulsating heat pipe with cylindrical shell-type condenser

Pulsating heat pipe (PHP) is a two-phase passive cooling device and has become an efficient heat transport system to replace bulky conductive straps in cryogenics applications. A two-turn cryogenic PHP is experimentally investigated with liquid nitrogen as working fluid in the present paper. A cylindrical shell-type condenser is proposed that provides a high cooling load with easy refilling of liquid nitrogen. The inner diameter of the capillary tube is 1.3 mm, and the outer diameter is 3.2 mm. The filling ratios are kept as 38%, 57%, 76%, and 95%. Heat input is varied in the range of 1 W-80 W. The maximum heat transport capacity of a two-turn cryogenic PHP with cylindrical shell-type condenser is observed 70 W before dry out. The maximum effective thermal conductivity (K-eff) of 16350 W/m-K is observed at an optimum filling ratio of 76%. Fast Fourier Transform (FFT) analysis showed cryogenic PHP's deterministic behaviour at the optimal stage with a frequency range of 0.62-1.56 Hz.

Automated summary

The experimental study on a two-turn cryogenic pulsating heat pipe (PHP) using liquid nitrogen as the working fluid is conducted in this paper. A cylindrical shell-type condenser is proposed to provide a high cooling load with easy refilling of liquid nitrogen. The maximum effective thermal conductivity of 16350 W/m-K is observed at an optimum filling ratio of 76% in the cryogenic PHP.