Approche éco-efficente de l'enlèvement sécuritaire du fluide hydraulique d'un aérodyne en fin de vie

Abstract

The important production of equipment items in all fields in recent decades depletes raw material sources. The management of end-of-life products is a principle that can respond to the depletion of these resources. Means of transport are subject to these pressures and aircrafts are representative in terms of volume and quality of the materials they contain. Hazardous materials in commercial aircraft become problematic during operations related to processing equipment. Hydraulic fluid used in commercial aircraft has characteristics representing risks to workers health and safety and the environment. Emptying by gravity flow used during securing operation does not eliminate projections and spills due to the fluid remained trapped in the pipes. Furthermore, the use of absorbents to recover fluid spills creates useless and costly activities and generates additional waste. Finding solutions for the removal of hydraulic fluid by controlling the associated risks is justified by the presence of environmental considerations into decision making. The removal of hydraulic fluid from aircraft pipes is made to avoid fluid over-contamination in order to facilitate its re-processing. The use of compressed air at low pressure is used to extract the fluid trapped in the pipe. Three laboratory prototypes are developed (1) to assess the trend which links the recovery rate of the fluid and the time-pressure, (2) to show the effect of the length and pressure drops of plane pipes and (3) to verify the application for a helicopter hydraulic system. The first manipulation with polyethylene pipes results in evaluating a logarithmic trend of the quantity of fluid ejected from the pipe in relation to the time under pressure. The rate of 95% of recovered fluid is reached after six seconds pressurizing compared to 86% recovery in the gravity emptying for two minutes. Experiments on airplane pipes show that in the case of a gravity drain, it is preferable to consider small circuit lengths to reduce the time drain. The tests performed on the helicopter hydraulic system result in an optimal time under pressure of 20 seconds for 95% of recovered fluid. The removal of hydraulic fluid from aircraft pipes by pressurized air allow to recover the fluid treatment, to improve working conditions, to reduce spills therefore the absorbent use and to avoid contamination of other materials. This method must be adapted to the different sections of an aircraft hydraulic system. The characteristics of hydraulic system pipes to define the optimum removal parameters are factors that can be incorporated in the principles of eco-design. The principles of the approach studied in areas such as industry, construction and medicine are potential pathways under certain conditions of scale matching.

Date	21 Aug 2014
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Mathias Glaus (Supervisor)