Experimental Evaluation of Overload Capability of an Annular Combustor Casing of a Gas Turbine Engine

Abstract

For the aero engine, size and weight of the combustors are important considerations along with long operating life and its overload capability. The combustor which is considered for this research has an annular shape with a thickness of 2 mm. The combustor casing is manufactured out of forging by machining to a thickness of 2 mm. This method has the advantage of better control of the thickness so that the desired thickness can be maintained throughout the component. Structural analysis has been carried out for the overload condition which is taken as twice the maximum operating pressure and at engine operating temperature analytically. The strength of the combustor casing has been evaluated analytically before subjecting it to experimental test. It is a mandatory requirement from the airworthiness point of view to evaluate its overload capability and to validate the manufacturing methodology by means of full scale rig tests before it is declared fit to fly. Details of the test facility, test adaptors, adaptation of the combustor to the test facility, instrumentation and the testing are presented in this paper. The component is inspected before starting the test and at the end of the test. No cracks and no change in dimensions are observed as per the inspection reports. The combustor casing has withstood the proof pressure test and demonstrated its overload capability for its safe life. The manufacturing process, that is, manufacturing of the combustor out of forging is also validated by means of this test.