Abstract
UDC 536.24
https://doi.org/10.52577/eom.2024.60.1.089
The design, principle of operation and results of the study of two-phase heat conductors, specifically loop thermosyphons with a horizontally located evaporator and condenser and a porous coating in the evaporator, intended for the thermal control of heat-loaded equipment are presented. Two modifications of thermosyphons were tested: 1) with a cylindrical evaporator and liquid cooling of the condenser; 2) with a flat evaporator and an air-cooled condenser. The porous wick contributes to the uniform distribution of the liquid as well as of the heat flow in the longitudinal and cross sections of the evaporator, the alignment of the temperature field over the surface of the evaporator and, consequently, of the cooled object. Thermosyphons are made of copper, working fluids were water and freon R245fa. The aim of the work was to determine the main thermal characteristics of the developed devices: heat transfer capacity, temperature fields along the body, thermal resistance of the thermosyphon and its parts at different thermal loads and filling levels with working fluids. Experimental equipment and research methods are described. The studied devices also have characteristics that allow them to be used in thermal control systems for objects with a high heat release intensity: low thermal resistances, stable operation in a wide range of heat flows, high heat transfer capacity (up to 1.5–1.7 kW), short start-up time, dynamic exit to a stationary mode when the heat load changes. The created devices are designed for the thermal control of electronic, electrical and other equipment with intense heat release.
Keywords: thermosyphon, heat pipe, heat transfer, cooling of electronics, thermal control.