Autonomous Devices with an Evaporation–Condensation Cycle for Thermal Control of Heat-Loaded Equipment

In this paper, the authors present the design, operating principle, and results from the study of two-phase heat conductors intended for thermal regulation of heat-loaded equipment: ring thermosyphons with a horizontally located evaporator and condenser and a porous coating in the evaporator. Two modifications of thermosyphons—with a cylindrical evaporator and liquid cooling of the condenser and with a flat evaporator and air cooling of the condenser—were tested. The porous wick promotes uniform distribution of liquid and heat flow in the longitudinal and cross sections of the evaporator and equalization of the temperature field over the surface of the evaporator and, consequently, the cooled object. Thermosyphons are made of copper, and the operating fluids are water and freon R245fa.