LAUSR

An experiment is conducted to test the transient characteristics of a re-entrant grooved wick heat pipe, and the transient thermal response characteristics of the ammonia-aluminum heat pipe in the horizontal status during startup and shutdown stage is analyzed. The transient axial distributions of the wall temperature of the heat pipe have been obtained. Moreover, the influence of heat load and operating temperature on the transient thermal characteristics have been analyzed. The results show that the axial wall temperature distribution of the heat pipe is quite uniform during startup and shutdown stage and rises more quickly in the early stage of the unsteady state than in the later stage. The effective thermal conductivity becomes lower when the heat input increases and shows a rapidly decreasing trend during the startup process while it remains nearly unchanged during the shutdown process. In the range of heat load and refrigerant temperature given in this experiment, the startup/shutdown response time of the re-entrant grooved wick heat pipe is approximately 3 min.