Numerical study of liquid nitrogen based pulsating heat pipe for cooling superconductors
Abstract Numerical simulation of a 2-D Cryogenic Pulsating Heat Pipe (CPHP) is carried out. Liquid nitrogen is considered as working fluid. The Volume of Fluid (VOF) model is used to simulate two-phase liquid-vapor flow in a CPHP. Filling Ratio (FR) is kept in the range of 25%-70%. The evaporator temperature is set in the range of 85 K-115 K. The condenser temperature of 76 K is set constant. The volume fraction results of liquid nitrogen are studied for different operational conditions. A detailed qualitative and quantitative analysis is performed for working fluid temperature, adiabatic wall temperature and flow circulation velocity. Power spectrum density (PSD) and the Autocorrelation function (ACF) tools are used to analyze adiabatic wall temperature-time series data. Thermal oscillations are observed with dominant frequency in the range of 0.25-1.85 Hz.