Investigation of Sensor Faults in a Gas Turbine

When testing gas turbine engines, a variety of flow parameters must be monitored. The precise measurement of total pressure and total temperature values is critical for evaluating the performance of the entire engine as well as individual engine components. Moreover, these parameters are used to define the control law and the engine health monitoring in an installed engine in operation conditions. The actual sensor design is often challenging due to the high temperatures and flow velocities within a gas turbine. This study's approach is based on separating the contributions of each component in the chain to the inaccuracy of the two systems, allowing for, first, a deeper understanding of the contributions of different parameters involved in defining the system's inaccuracy and, second, the formulation of inaccuracy forecast highlighted in a modern engine. For the temperature measurement system inaccuracy, a thermocouple in MIMS configuration with an exposed junction was considered. The indicated temperature is primarily influenced by systematic errors caused by the design of the sensor probe, whereas thermocouple drift has less of an impact on the contribution of the deviation temperature: because the errors in the individual components of the chain are in the same order as the inaccuracy of the Type K thermocouple, they cannot be neglected. The probe's design is critical for pressure measurement system inaccuracy, while error from other components of the pressure chain has little impact, which could be omitted due to the high pressure inside the engine.