In October 1990 a research and production unit of heat pipes was created at Lavochkin Association, JSC.
Over these years a significant experience of development, production and testing of thermal control systems based on heat pipes and honeycomb panels for ensuring thermal control of the SC has been gained.
Arterial heat pipesThe Heat pipes unit has developed unique heat pipes with a near-wall segmental artery. The arterial design of the capillary structure allows to increase the power of heat pipes without increasing their mass characteristics, increase their resource, radiation resistance and reliability. Flexible, diode, gas-controlled and cryogenic heat pipes of various shapes and configurations have been created based on the arterial design of the capillary structure. The stainless steel application enables using almost any heat carriers. The service life is up to 25 years from the moment of refueling. With an effective length of 1.0 m, an external 12 mm and an artery height of 2.5 mm, the maximum transmitted power for different arterial heat pipes heat carriers is shown in Figure No. 3.
Axial heat pipesThe heat pipes unit has created a family of axial heat pipes made of aluminum alloy AD31 (6063) with heat carriers’ ammonia, propylene, ethane, methane, nitrogen and of a diameter fr om 6 to 20 mm. In terms of their thermophysical characteristics, reliability and resource, axial heat pipes are not inferior to the best world samples and have passed qualification tests for compliance with Russian and European ESA PSS-049 standards. The service life is up to 25 years from the moment of refueling. The dependence of the heat transfer capacity of the axial heat pipes on the operating temperature without considering the boiling lim it, provided that heat input is from above and output from below.
Loop heat pipes
The most important area of activity of the heat pipes unit is the production and testing of loop heat pipes (LHP).
The first successful flight experiment with LHP was performed on the board of Granat SC on the 1 st December 1989. Operational stability of LHPs during more than 10 years proved the possibility of using these devices in service systems of thermal control.
LHPs can transmit large heat flows up to 10 kW in an arbitrary direction in the field of mass forces over long distances and provide opportunities for their regulation. LHPs have a finely dispersed capillary structure in an evaporator operating in the "inverted meniscus" mode. The channels for liquid and steam are separated and the minimum outer diameter of which is 2 mm. Aluminum, nickel, titanium, and stainless steel are used to manufacture the LHP body. The service life is at least 25 years.
With the appearance of LHPs, a new stage of development of thermal control systems has begun. The use of LHPs made it possible to proceed to the construction of the spacecraft layout according to the modular principle.
Today, LHPs are used in almost all spacecraft produced at Lavochkin Association, JSC, as well as in the designs of other enterprises in the industry. More than 500 LHPs have been launched as part of Russian and foreign SCs.
Honeycomb panels (HCP)Heat pipes unit has developed thermal honeycomb panels (THP), which are used as structural elements of the SC, TCS elements, including radiators. Structurally, the honeycomb panel is a glued multilayer structure..
ТTHPs are produced according unified technical standards:
- Overall dimensions is up to 3000*2800*40 mm.
- Plate thickness is from 0,3 mm up to 1,0 mm, alloy В95.
- The number of thermal pipes and embedded elements is up to tens of thousand of pieces.
- Thermooptical coating can be applied on outer plates of THPs: Ekom-1 white Enamel and TRP К208SrE.
- Specific weight of THP is from 4 kg/m 2
For our products, the cycle of producing a new honeycomb panel is less than 1 month from the moment the design documentation is issued.