Loop heat pipe (LHP) is a quite promising two-phase heat transfer device, holding significant application potential in the modern electronics cooling. In this work, a LHP-based cooling system has been developed, which features no power consumption and no noise, taking full advantage of LHP's efficient longdistance heat transport capability. The heat source was simulated by a film electric resistance heater, which was connected to the cylindrical evaporator of the LHP through an aluminum saddle. The condenser line was embedded into the bottom surface of a fin radiator with a relatively large volume, where heat dissipation to the ambient was completely in the form of air natural convection. Extensive experiments on this cooling system were conducted, mainly focusing on its startup and system thermal resistance. Experimental results show that this cooling system can successfully realize the startup with a very small heat load. With the film heater temperature not exceeding 80 , this cooling system can dissipate a heat load up to 150 W to the ambient at a temperature about 24 , corresponding to a system thermal resistance about 0.30 /W. In addition, this cooling system exhibited very strong anti-gravity capability. With an adverse elevation of 0.5 m, the cooling system can realize normal operation, and no obvious performance decay was observed except an increased operating temperature at small heat loads.

This is a repository copy of Experimental study on a dual compensation chamber loop heat pipe with dual bayonet tubes.

In order to push forward the commercial applications of loop heat pipe (LHP) especially in an environment where people are present, it is of great importance to explore alternative working fluids to substitute the commonly used anhydrous ammonia. In this work, an acetone-charged LHP with a nickel wick is developed and experimentally studied, mainly focusing on its startup and heat transport capability. Based on the experimental results and theoretical analysis, some important conclusions have been drawn, as summarized below: 1) The acetone-charged LHP with 2 mm inner diameter pipeline can successfully realize the startup, and reach a heat transport capability of 60W×0.5m; 2) When the inner diameter of the pipeline is increased from 2 to 4 mm, the LHP can start up with a much smaller heat load, i.e., 5 W, achieving a much lower steady-state operating temperature; 3) When the inner diameter of the pipeline is increased from 2 to 4 mm, the heat transport capability of the acetonecharged LHP can be increased from 60 to 100 W. 4) Adverse elevation affects greatly the heat transport capability of the acetone-charged LHP. With the adverse elevation increasing from 0 to 0.2 m, the heat transport capability is decreased from 100 to 60 W. The physical mechanisms responsible for the experimental results mentioned above have been analyzed and discussed. This work contributes to a better understanding on the operating performance and characteristics of the acetone-charged LHP, providing good design guidance and reference for its future applications.

The AYERM code is a conputer program which has been developed for the high-temperature gas-cooled reactor (HTGR) safety research program. It is a conjunction of the heat conduction code, AYER, and a set of special subroutines. This modified AYER code can predict the timedependent release of volatile fission products from a reactor core during a hypothetical loss-of-forced-circulation (LOFC) accident. The computation scheme is based on the finite element method. The function of the AYER code is to compute the temperature distribution and the temperature history of a reactor during an LOFC accident. The subroutines perform two functions. One group of the subroutines provides the essential input data, such as the properties, configuration, initial and boundary conditions, etc., of the reactor core. The other group combines the computed instant local temperature with the fuel model parameters (i.e., the decay and release constants, and the irradiation history of the fuel) to perform the fission product release calculations. I.