The delivery of high-fidelity multi-physics models to be used as virtual test bench for valve and actuator performance is achieved through a framework of activities involving materials characterisation (WP2, WP6), bespoke friction and aerodynamic testing (WP3, WP4, WP5), and development of state-of-the-art multi-physics numerical and analytic models (WP7).
The project has spent most of its first eighteen months focussing on foundation work for the implementation of an extensive experimental programme, based on which the development and calibration of multi-physics models will be undertaken. An extensive material characterisation programme was also initiated, which provides the numerical models with a comprehensive and parametric database of properties for the materials used in pneumatic valve systems.
Activities in WP2 are undertaken by TWI and aims to develop a coefficient of friction database for selected material couples. Activities undertaken as part of WP2 until now include: definition of a test plan and procurement of material samples for testing; development and setup of a friction coefficient test bench to cover environmental temperatures between -50°C and 700°C and contact pressures in the range 0.1MPa to 1GPa; a comprehensive experimental test programme to determine static and kinetic coefficients of friction for the required operational environment and this is currently in progress.
WP3 and WP4, led by SCITEK and currently in progress, aim to commission specifically designed friction test benches to measure the friction contribution of real-scale components used in pneumatic valve configurations in bleed systems. Based on technical specifications agreed with the Topic Manager, the test benches mentioned above were designed, manufactured and commissioned. The test benches will offer the possibility to tests several configuration of seal systems and to output the friction generated by the same seals as function of a wide range of values of relevant parameters, such as velocity, operating pressure and environmental temperature (-50°C and 700°C). The experimental programme has now started and is currently ongoing.
WP5 activities cover the fluid dynamics domain of the pneumatic valve investigation and will provide the project with experimental results in terms of aerodynamic torque performance and its influence on the friction contribution of the pneumatic valve components. An experimental test bench will be designed and commissioned to test real-scale components and a testing programme will be undertaken to generate experimental data for the calibration of the models. To date, the specifications and requirements for the test bench have been defined and agreed, and the design process has already started and is currently in progress. Activities in WP5 are led and undertaken by ESI and Ventil.
Finally, WP7 includes all those activities aimed to the development of multi-physics numerical and analytical models of pneumatic components. Thermal physics, mechanical physics and fluid mechanics models will be developed and calibrated against the experimental results obtained from the friction tests, aerodynamic torque tests and from the diaphragm materials characterisation study undertaken in the other work packages. A comprehensive theoretical study, including a critical review of existing numerical friction models capable of incorporating various phenomena (e.g. hysteric dynamical behaviour during pre-sliding, friction lag or non-reversibility of friction force, Stribeck effect) was undertaken. The development of the numerical models was initiated and are currently being implemented.
