Assessment of the Engine Installation Performance of a Redesigned Tiltrotor Intake System

The always growing interest that rotorcraft manufacturers on reducing the environmental impact of their products pushes toward the development of specific methodologies devoted to propulsive efficiency optimization and evaluation of gas turbine engine performance. In particular, the determination of benefits that re-design and optimization of airframe engine installation components have on fuel consumption assume a relevant position in the design process. Optimized inlet and exhaust geometries can be obtained by coupling CFD codes with advanced optimization algorithms, automatically searching for optimal solutions among a prescribed search space. The consortium constituted by the University of Padova (UNIPD) and the spin-off company HIT09 successfully applied this automatic optimization approach to several components of the European tilt rotor ERICA, including engine installation. In this paper, the assessment of the engine performance gain given by such optimization is done using an engine off design performance prediction software, TSHAFT. First, a brief presentation of the code, developed at UNIPD, is given, along with validations carried out on a specific test case found in literature, for which experimental data are known. Subsequently, TSHAFT is employed in the ERICA case, taking into account inlet flow distortion effects. An exhaustive performance comparison between baseline and optimized engine installations is provided, highlighting the remarkable improvement in engine efficiency and compressor stability achieved by means of the optimization method implemented.