Improved aerothermodynamic instrumentation of an Allison T63-A-700 gas turbine engine

Abstract

This document describes the design, installation, and operation of an improved measurement system for the aerothermodynamic flow path states in an Allison T63-A-700 (C250-18 civilian designation). Temperature measurements for the gas generator turbine and exhaust state points were evaluated and average values were calculated. The measurement uncertainty for airflow, fuel flow, and output power has been reduced to less than 3%. State points match installation design data within 3%. The digital scanning array has improved the accuracy of the pressure measurements and added the ability to measure pressure differences over time. The added bellmouth pressure sensors provide a redundant pressure measurement that is more accurate than the dynamometer system. The gas generator turbine inlet and exhaust temperature profiles have been measured and show that the temperature profile becomes less symmetrical with increasing air and fuel flow. The measurement values for the gas generator inlet temperature have been consolidated into a single value that is about 50 degrees different from expected values. The temperature profile at the power turbine inlet shows how the hot spot at the gas generator turbine inlet is affected by the swirl produced by the power turbine stages. The time resolved fluctuations in pressure between the compressor and gas generator turbine have been measured and show that compressor discharge and gas generator turbine inlet pressures are similar.