Project Title:

High-Performance, High-Temperature Heat Pipes

03.08-0236
High-Performance, High-Temperature Heat Pipes
Ultramet
12173 Montague Street
Pacoima, CA 91331
J. Grady Sheek  (818-899-0236)
LaRC -- NAS1-18644

Abstract:

	 A reliable, efficient means for moving large amounts of heat from the source to
a heat sink will be required for thermal management systems in future aerospace applications
such as trans-atmospheric vehicles. The heat pipe is just such a device and, through
proper selection of the case material and working fluid, can operate nearly isothermally
from 5-2300 K. Heat pipes have been produced since the 1960's. This project, however,
addresses a unique and innovative method of producing seamless heat pipes utilizing
the process of chemical vapor deposition (CVD) and chemical vapor infiltration (CVI).
Since the resulting heat pipe will be seamless with the exception of the fill port,
it should have a high inherent reliability.
	In Phase I, the process for making heat pipes was demonstrated. Vapor passages were
drilled through the thickness of reticulated carbon foam which was then infiltrated
with tungsten to provide the capillary wick structure. A tungsten wick is suitable
 for most liquid metal working fluids. The porosity of the foam was then bridged
by CVD to create a wall over the part. The heat pipe was successfully tested using
methanol as a working fluid.

Potential Commercial Application:

Potential Commercial Application: This innovative heat pipe design will meet the
requirements of thermal management systems for future aerospace applications which
will have to be able to move massive amounts of heat and will require materials or
devices with high thermal conductivity.