Fabrication and Testing of Mo-Re Heat Pipes Embedded in Carbon/Carbon

Abstract

Two heat-pipe test articles were fabricated and tested, furthering the development of a refractory-composite/heatpipe-cooled leading edge. A 3-ft-long, molybdenum-rhenium heat pipe with lithium working uid was fabricated and tested in a vacuum chamber at an operating temperature of 2460 ± F, verifying the heat-pipe design. Following the fabrication of the initial heat pipe, three additional heat pipes were fabricated and embedded in carbon/carbon. The carbon/carbon heat-pipe test article was successfully tested using quartz lamps in a vacuum chamber in both horizontal and vertical orientations. Startup and steady-state data indicated similar operation in both orientations but different behavior among the three heat pipes. Radiography and eddy current evaluations were performed on the test article and indicated differing carbon/carbon thicknesses and a potential disbond.Nomenclature d = artery diameter, in. m = mass of lithium in heat pipe, lb P = pressure, psi q = heat ux, Btu/s q 00 = heat ux per area, Btu/ft 2 -s r = radius, in. T = temperature, ± F t = time, s V = voltage, V x = distance from end of carbon/carbon, in.

Thermal Management at Hypersonic Leading Edges

“…by heating fuel). Several heat pipe concepts have been explored [33], [34], [35], [36], including the development of a heat pipe leading edge for the Space Shuttle Orbiter [33]. ________________________________________________________________________ Because passive concepts suffer from both excessive mass (case 1) and low fracture toughness (case 2), and the added complexity of an active concept is not desirable, we limit further discussion here to the passive concepts of cases 3 to 5; namely ablative, hot structure, and heat pipe TPS, which are most suited for the thermo-mechanical stress state at a hypersonic vehicle's leading edges.…”

“…The concept of coupling heat pipes to leading edges has received only limited investigation [34], [35], [36], [75], [76]. Nearly all leading edge heat pipe concepts employed arrays of hollow circular tubes or channels either metallurgically joined to a high temperature skin or embedded in a wedge-shaped composite [33], [34], [35], [36].…”

“…Nearly all leading edge heat pipe concepts employed arrays of hollow circular tubes or channels either metallurgically joined to a high temperature skin or embedded in a wedge-shaped composite [33], [34], [35], [36]. The heat pipes were bent to conform to the radius of the leading edge.…”

“…Iso-Mach lines ( ) have been added for reference. Flight data compiled from [3], [7], [20], [21], [22] (a) An Orbiter leading edge developed by NASA using a Hastelloy X and sodium working fluid [33], and (b) a Mo-Re heat pipe embedded in a RCC leading edge skin [35] Carolina, mankind has aspired for faster flight vehicles which push the limits of engineering.…”

Heat-balance Thermal Protection with Heat Pipes for Hypersonic Vehicle

“…5). From 1992 to 2006, Glass [22][23][24][25][26][27][28][29] did a lot of research on heat-pipe-cooled leading edge by theory analysis, numerical simulation and experiments. During their tests, the heat-pipe-cooled leading edge worked nearly isothermally.…”