Passive Energy Recovery System Applied to Aeronautical Environment Testing Rig Results 2013-01-2272
The optimisation of energy is of the upmost importance within any vehicle and is a key driver in the design of all aeronautical projects. Modern aviation is trending towards the “More Electric Aircraft” (MEA), a model of increased electric power demand whereby traditional hydraulic, mechanical and pneumatic systems are replaced by electrical ones.
This paper is based on the development project entitled “Advanced Thermal Management in Aeronautics” (ATMIA). The main target of which was to examine the potential for Loop Heat Pipes (LHPs) to be used in an aeronautical platform as assessed in previous the paper ref. 1. Until now the use of LHPs has been primarily on aerospace platforms. Project ATMIA addressed some specific requirements for an aeronautical platform such as the effects of vibrations, gravity and the possibility of disassembling for maintenance and transportation.
LHPs are a technology that focuses on a thermal management philosophy that allows free-energy heat transportation. They are completely passive two-phase heat transfer devices that control the transfer of energy between certain subsystems without needing additional power consumption. They utilise the evaporation and condensation of a working fluid to transfer heat and capillary forces developed in fine porous wicks to circulate the fluid. LHPs are known for their high pumping capability, robust operation, low weight and high thermal conductivity.
The use of LHPs can potentially reduce the power needed by a system and hence reduce the energy to be extracted from the engines. This decrease in engine power taken together with a potential reduction in weight directly improves fuel consumption. This can lead to a reduction in fuel used, increased efficiency and range, improved payload capacity and the reduction of CO2.
The primary objective of this phase was to validate a concept study described in the previous paper ref. 2 and to demonstrate the possible use of LHPs on aircraft as a thermal management system using a laboratory test rig. Several tests were performed to analyse the performance of LHPs with aeronautical material and to investigate how much energy can be extracted from an aircraft's hot sources and transported to two different cold sources, both of which must be able to operate individually or simultaneously. During different flight conditions aircrafts operate within wide temperature ranges, hence there are some phases of the flight where one heat source can be useful to heat up one element and other where cooling might be necessary. Based on this, one of the main drivers of the project was the possibility of controlling and monitoring to which source the heat goes.
The test rig layout included a real carbon fibre leading edge and a real fuel tank enclosed within a commercial refrigerator to simulate low ambient temperatures. An electrical heater was used to simulate the hot source. In this rig the behaviour of the LHP was tested. Different scenarios were simulated.