Development of a high temperature cooled fast response probe for gas turbine applications

The measurement of unsteady pressures within the hot components of gas turbine engines still remains a true challenge for test engineers. Several high temperature pressure sensors have been developed but so far their applications are restricted to unsteady wall static pressure measurements. Because of the severe flow conditions such as turbine inlet temperatures of 1700°C and pressures of 50 bar or more in the most advanced aero-engine designs; few (if any) experimental techniques exist to measure the time-resolved flow total pressure inside the gas path. In this thesis, the development as well as the first experimental engine and test rig results obtained from a fast response cooled total pressure probe are presented. The designed probe was successfully tested at the turbine exit of a Rolls-Royce Viper turbojet engine, at exhaust temperatures around 750°C and in the Rolls-Royce intermediate pressure burner rig, at temperatures above 1600°C. Following tests with the first probe manufactured, several improvements were made on the probe design. The new probe was tested on a Volvo RM12 engine, at exhaust temperatures above 900°C. During the course of this study, hot sections of turbomachines are accessed for the first time using fast-response instrumentation. Following this milestone, the new area of research in turbomachinery instrumentation field will be the quantification and correction of measurement errors in high-temperature environments.