Experimental investigation of oscillating heat pipes

Operation requirements of oscillating heat pipes (OHPs) are proposed. Based on the requirements, OHPs with nonflammable fluorocarbon fluids, FC-72 and FC-75, as the working fluid are developed. The OHPs have an inner diameter of 1.75 mm, a total length of 446 mm and 40 tubing turns. There is one evaporator in the middle and two condensers on both outer sides of the OHPs. Thermal performance tests are conducted at various operating temperatures and heat rates. The working fluid fill ratio is varied. A high performance OHP with FC-72 has been indicated for the first time. The FC-72 OHP can transport 2040 W heat rate without dryout. The gravitational acceleration does not have noticeable influence on the performance of the fluorocarbon OHP. The thermal performances of the fluorocarbon OHPs are compared with the case of an acetone OHP.