Heat Pipe Solutions: Flexible Heat Pipes
Flexible heat pipes give designers the freedom to specify moving actuators, remote terminals and other components while maintaining thermal control in rugged and demanding environments. Aavid’s flexible heat pipes have been qualified for use in military aircraft specifically, for cooling electronics on the More Electric Aircraft and ultimately the All Electric Aircraft.
Aavid flexible heat pipes let engineers place controls in areas that maximize maintainability and reliability, while overcoming harsh thermal conditions. That’s why flexible heat pipes are particularly valuable in military and aerospace and avionics designs.
Flexible heat pipes can also be used as building blocks for innovative systems to meet emerging aerospace challenges. Aavid's Flexible Heat Pipe Cold Plate, available in four different configurations, solves cooling problems through a plate that transfers electronic heat to the most convenient heat sink via a flexible heat pipe. The flexibility allows relative motion between the heat sink and the component to be cooled which increasing durability and mean time between failures.
Flexible heat pipes can be installed on curved cold plates as well. In some applications, Aavid flexible heat pipes have been thermal cycled from -55° C to +65° C and flex fatigue tested to more than 5 million cycles with no sign of failure.
Aavid's flexible heat pipes have been proven under the following conditions:
•Aircraft Level Vibration Tested: F-18 vibration, shock and acoustic noise design requirements and test procedures for aircraft equipment
•Thermal Cycle Tested: Freeze/thaw cycle testing between -60° C and 135° C
How Can Heat Pipes Be Made Flexible?
Heat pipes are made flexible by inserting a flexible bellows section between the evaporator heat input section and the condenser heat output section. Flexible heat pipes are made from a wide range of metal materials and use a variety of working fluids depending on the application.
Flexible heat pipes can be installed in either gravity-aiding or against-gravity orientations. The against-gravity orientation is possible because of Aavid’s proprietary flexible wick structures used to return the working fluid to the evaporator section. The cold plate portion attaches to the surface to be cooled and the other end attaches to the heat sink. The flexible section allows for ease of installation, and it accommodates any relative motion between the heat source and the heat sink. The condenser region can be cooled by air cooled fins, like many Aavid products.