ICE PROTECTION THERMAL MODELLING TECHNIQUES

Rotorcraft present unique problems during the analysis, design and test of ice protection systems because of the need to provide protection for both rotating and non-rotating subsystems from the detrimental effects of ice accretion, ice shedding and ice ingestion over a wide range of flight icing conditions. While much experimental effort has and is going into the investigation of non-thermal ice protection approaches such as pneumatic boots, fluid or electro-impulse, thermal systems currently present the only proven means to achieve satisfactory protection of ice sensitive subsystems such as rotors, engine inlets, windshields, sensors and probes. The need, therefore, is to determine the most efficient use of local power distribution and power-on times through the use of impingement analyses and thermal modelling techniques for both steady state and transient conditions that can account for the icing environmental conditions as well as the structural (i.e., material properties) considerations.