Combined LHP and PHP based heat-transfer system

• A heat-transfer system based on a loop and a pulsating heat pipe was developed.
• Tests were conducted at different orientations in the gravity field and temperatures.
• Results have shown the system operating capacity for all test conditions.
• The system total thermal resistance achieved a minimum value of 0.28 °C/W.

The paper presents the results of development and experimental investigation of a heat-transfer system consisting of a pulsating and a loop heat pipe. The pulsating heat pipe (PHP) was made of a copper capillary tube 2 mm in diameter and located on an aluminum plate measuring 260 × 200 × 1 mm, had a thermal contact with the evaporator interface of a loop heat pipe (LHP) 0.6 m long. The working fluid of the PHP was R141b. The LHP was filled with ammonia. A heat-load source measuring 200 × 200 mm was located on the PHP, and its heat was transferred to the LHP evaporator. Tests were conducted at different orientations in the gravity field at heat loads from 10 to 170 W and heat-sink temperatures from −20 to +20 °C. A minimum value of thermal resistance equal to 0.28 °C/W was achieved in the heat load range from 50 to 90 W.