Ice Crystal Icing Test Design and Execution for the ALF502 Vane Segment in the NRC RATFac Cascade Rig 2019-01-1925

Understanding the behaviour of ice crystal ice (ICI) accretion and shedding inside an aircraft engine is important for safe and reliable engine operation in flight and to meet new airworthiness regulations. A significant advancement in this understanding came from two engine test campaigns carried out on a Honeywell ALF502 turbofan, led by the Ice Crystal Consortium (ICC) and NASA. However, it is often desirable to conduct smaller scale component level tests to both decrease costs and increase the amount of data obtainable, given a component is more accessible when removed from an engine and therefore easier to instrument and observe. That was the purpose of the work discussed in this paper where a segment of an ALF502 low pressure exit guide vane ring was installed in the NRC RATFac ICI cascade rig. The existing cascade rig was modified to accommodate the vane segment which allowed for the instrumentation already available on the rig to be used to characterize the ICI environment. The test article fixturing was designed to match the engine aerodynamics as much as possible but also allow for a large suite of instrumentation including temperatures, pressures, video, ultrasound ice accretion sensors and systems for wall heating and anti-icing. The test was able to characterize accretion versus a wide range of ICI conditions, determine the effect of wall heating and define accretion boundaries. With the wide range of test parameters that were independently and precisely controlled and the instrumentation available to measure them, the understanding of accretion in the vane segment was expanded relative to that seen in the engine test. Accretion was seen on the test article in the location observed in the engine with similar morphology. Further analysis of the test data could demonstrate the added value of a rotating rig test.