N112-093 TITLE: Innovative Heat Sink Technology for Application to Aircraft Systems

TECHNOLOGY AREAS: Air Platform

ACQUISITION PROGRAM: PMA-231, C-2 / E-2 Program

OBJECTIVE: Develop and demonstrate innovative heat sink technology and/or different methods of heat sink utilization that can be used to provide supplemental cooling for aircraft systems and/or components.

DESCRIPTION: Methods are needed to increase mission capability of thermal management systems. Thermal management is widely viewed as one of the key challenges for next-generation tactical aircraft systems. Fourth- and fifth-generation tactical aircraft are already pushing the envelope for cooling capacities; typical heat rejection requirements for these aircraft are in the neighborhood of 30-40 kW. For these aircraft, there are portions of the flight envelope where the environmental control system or thermal management system cannot provide adequate cooling capability for mission systems or air vehicle equipment. Furthermore, these heat loads are projected to increase significantly in next-generation fighter aircraft with the potential introduction of directed energy weapons (DEWs) and other high-power mission systems. DEWs provide a good example of the type of equipment that might present particular challenges for future aircraft � transient, high-power (approximately 1MW), short duration. Such systems may require an order-of-magnitude increase in heat rejection capacity. Complicating matters further is the conflicting survivability requirement which includes reducing heat sources radiating or exhausting from the aircraft. This means that, at least in threat environments, thermal management must be performed adiabatically. State-of-the-art for current-generation tactical aircraft typically consists of one or more bootstrap air cycles, supplemented by liquid cooling circuits. Compressed air for the air cycle is extracted from engine bleed air (approximately 1100 degrees F), and delivery air temperature for avionics and mission systems is approximately 30-40 degrees F. Fuel is also used increasingly as a heat sink, but there are limits to fuel temperature, and fuel burn during the mission decreases the size of the available heat sink. Possible ways to regain cooling margin may include new materials and technologies as well as innovative applications of new and existing technologies. Advanced heat sink technology can either be applied to improve heat transfer at the individual weapon-replaceable assembly level or be integrated into the aircraft�s cooling system.

PHASE I: Conceptualize and design an innovative, lightweight, durable, heat sink technology or demonstrate the feasibility of applying existing heat sink technology in an innovative manner that will result in a sufficient cooling margin.

PHASE II: Provide practical implementation of a production-scalable process to implement the recommended approach developed under Phase I. Evaluate the approach by showing concept maturity, initial fabrication of a prototype, and capabilities validated. Develop an integration hardware design scheme to add a developed system to improve thermal performance.

PHASE III: Transition the approach to appropriate platforms, systems, or hardware.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Heat sink technology can be used to solve various similar thermal problems within aircraft and ships, both military and commercial.

REFERENCES:
1. Wong, R. & Lui, C. (2003, July). Dual expansion energy recovery (DEER) environmental control system. Paper presented at the International Conference on Environmental Systems, Vancouver, BC, Canada. Retrieved from http://papers.sae.org/2003-01-2399/;WebLogicSession=MYkZt3jyHLL0H6c7nLHH1w4FyHrX4LKT3qSJhVWp1vvf9JQXKfVj!-1234461123

2. Lillibridge, S. T. & Stephan, R. (2009, July). Phase change material heat exchanger life test. Paper presented at the International Conference on Environmental Systems, Savannah, GA. Retrieved from http://papers.sae.org/2009-01-2589/

3. Aldoss, T., Ewing , D. J., Zhao, Y. & Ma, L. (2009). Numerical investigation of phase change materials for thermal management systems. SAE International Journal of Materials and Manufacturing, 2(1), 85-91. Retrieved from http://saematman.saejournals.org/content/2/1/85.abstract

KEYWORDS: heat sink; thermal capacitance; electronic overheat; endothermic agent; thermal storage; thermal transfer; avionics

** TOPIC AUTHOR (TPOC) **

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