Development and Investigation of a Miniature Copper-Acetone Loop Heat Pipe with a Flat Evaporator

Abstract

The paper presents the results of development and investigation of a copper miniature loop heat pipe (LHP) with acetone as a working fluid. The device was equipped with a flat evaporator measuring 80 ´ 42 ´ 7 mm and vapor and liquid lines with an outside diameter of 3 mm, whose lengths were 145 mm and 175 mm, respectively. The LHP was tested at heat loads from 5 W to 60 W, different orientations in the gravity field and heat-sink temperatures from −40˚C to +50˚C. It is shown that the LHP retains its efficiency at all testing conditions. It is also mentioned that at a heat-sink temperature of +50˚C the device operates in the mode of constant conductivity in the whole range of heat loads, and in this case a minimum thermal resistance of the “heat source-heat sink” system equal to 0.16˚C/W is achieved, which is independent of the LHP orientation in the gravity field.