Compact and non-intrusive heat flux sensor for advanced propulsion systems

The rotating detonation engine (RDE) is an emerging next-generation propulsion device that is being investigated within AFRL. The harsh environment in RDE, having high impulses of both temperature and pressure, often destroys combustor components. The thermal stresses – which are directly correlated to the heat flux – produced in the components is a major factor in component failure. Thermal management schemes and new materials need to be developed to allow safe operation of this device. However, current state-of-the-art heat flux measurement sensors are either destroyed by the RDE or are inaccurate at the relevant conditions. An innovative heat flux sensor proposed in this work utilizes non-contact, long-wave-infrared thermal radiation technology to accurately measure the component heat flux. The device will be protected to survive these harsh environments and will be versatile enough to be used in various military gas-turbine engines. In addition, this device has a strong need in the commercial airline market. Current commercial aircrafts undergo engine maintenance on a schedule based on the number of operation hours. Using this sensor, a condition-based approach can be implemented to determine when maintenance is necessary based on the engine conditions. Ultimately this will lead to more economical and safer engine operation.