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Current Research


Main achievements:
  • creation of loop heat pipes - highly efficient heat-transfer devices for different purposes;
  • creation of new capillary-porous materials for heat-transfer devices with high capillary-transportation characteristics.
Loop Heat Pipes


     Loop heat pipes (LHPs) are hermetically sealed heat-transfer devices, possessing a superflow thermal resistance and operating on a closed evaporation-condensation cycle with the use of a "capillary mechanism" for pumping the working fluid. LHPs are capable of transferring heat flows from several watts to several kilowatts at a different orientation in the gravity field and zero-g conditions without the use of any additional energy sources.

LHP Schematic Diagram

LHP Schematic Diagram


     Advantages of LHPs:
  • high heat-transfer capacity;
  • no mechanically mobile parts;
  • low specific consumption of materials;
  • reliability in operation;
  • no need to provide a regular service;
  • adaptability to different arrangement conditions;
  • practically unlimited operating resource;
  • wide opportunities for various design embodiments.
  • low sensitivity to changes of the position in space;
Main Technical Characteristics of LHPs

     maximum capacity, W100 2000     
     thermal resistance, /W0,02 0,2     
     operating temperature, -20 180     
     effective length, m 0,2 20     
     evaporator diameter, mm5 30     
     diameter of vapor line and condenser line, mm1,8 8     

     At present LHPs are successfully used in systems of thermal regulation of space equipment.

     Promising fields of practical application:

  • cooling of computers,
  • cooling of electronic and electrotechnical devices,
  • systems of heating of different objects,
  • low-potential heat recovery, etc.
LHP Experimental Models

Ammonia LHP
(20 m in length, capacity of 1.7 kW)

Ammonia LHP

LHP with a disk-shaped evaporator
(30 mm in diameter)

LHP with a disk-shaped evaporator

LHP in Tests
(2 m in length)

LHP in Tests

     A high capacity copper-water LHP with the effective length of 310 mm was developed. This devise has a flat-oval evaporator which thickness is 7 mm and has the vapor and liquid lines with 6 mm diameter. The size of the evaporator active zone is 32 mm x 32 mm.

General view of the copper-water LHP

     The tests of LHP were carried out with the heat sources which have 1 cm2 and 9 cm2 heat surfaces. The condenser was cooled by the running water under the temperature of 20C. The maximum heat flux in the heating area with 1 cm2 heat source was 998 W/cm2, and with 9 cm2 heat source it was 134 W/cm2. The minimal LHP thermal resistance of 0,044C/W was reached under the 1200W heat load and the heat source temperature of 143,5C.

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      Heat load dependence of the heat source temperature, obtained in tests of a copper-water loop heat pipe with the liquid condenser cooling at 20