Experimental Investigation on the Thermal Performances of a New Design of Pulsating Heat Pipe With Two Condensers

In this paper, for the first time, a novel design of pulsating heat pipe (PHP) with one evaporator and two condensers located on both sides of the evaporator at an angle to the horizon was proposed, manufactured, and experimentally investigated for the purpose of use in cooling systems for electronic devices operating in a tilted position. The PHP body is made of a copper capillary tube with an inner diameter of 1.5 mm. The working fluid is methanol. The number of turns is 4. The heating zone dimensions are 60 mm × 36 mm, and the cooling zone dimensions are 200 mm × 35 mm. The РНР condensers were cooled by aluminum radiators blown by two fans with an air flowrate of 5.2 m³ h^–1. The launch of the РНР began with a power of 30 W at all positive tilt angles and in a horizontal position. The dependences of the temperature in the heating and cooling zones and the PHP thermal resistance both on the power input (from 30 W to 200 W) and on the orientation in space (at tilt angles of 0 deg, 15 deg, 30 deg, 60 deg, 90 deg) were obtained. It is shown that when the evaporator is located below the condensers, the РНР works stably. Moreover, in the power range from 120 W to 200 W, the tilt angle practically does not affect the thermal resistance of the PHP. A comparison of the thermal resistance of the developed РНР with known РНРs filled with methanol showed the high efficiency of the developed РНР: at power input from 120 W to 200 W, the thermal resistance was from 0.2 °С W^–1 to 0.18 °С W^–1. The developed РНР design is promising for use in air cooling systems, for instance, of radar transmit/receive modules and high-power LED lighting systems.