Experimental investigation of the characteristics of cryogenic oscillating heat pipe

The oscillating heat pipe (OHP) with high thermal performance and easy manufacturing has been increasingly studied in the recent years. In this paper, the OHP for cryogenic application is investigated. An OHP system is manufactured with 3 sections of evaporator, condenser and adiabatic section. The temperature of evaporator and condenser and the gas pressure of the OHP are measured. The experiments with working fluid of nitrogen are carried out. When the heat input increases, the temperature and pressure increases were observed experimentally. When the dry-out takes place, the evaporator temperature rises quickly, the gas pressure drops sharply and the amplitude of the pressure oscillation reduces largely. The effective thermal conductivity is obtained and compared to other literatures. The relation between the effective thermal conductivity and the gravity, and the relation between the gas pressure and the gravity are attempted to interpret. The cryogenic OHP system shows much higher thermal performance than high purity metal, and it requires more study on the geometric optimization, the selection of working fluid and the operating limitations.