Instrumentation for Hypersonic, Air-breathing Engines

The operating conditions of air-breathing propulsion engines demand designs that include cooling by the fuel and use of lightweight materials that withstand extreme heat fluxes under oxidizing conditions. Currently there are no means to non-invasively measure the fuel temperature with the required temporal and spatial resolution. It is important to monitor and maintain the maximum fuel temperature below critical levels in order to prevent coking. For ground-based experiments, real-time fuel temperature measurements can be used to relax safety constraints, thereby allowing for higher speed flow and longer length experiments. Furthermore, experience, information, and instrumentation developed as the result of ground-based experiments can form the basis for in-flight test capability. Flight hardened test capability can be incorporated as part of a control strategy that would enhance overall combustor efficiency by balancing fuel flow rates with combustor wall temperature to yield the most optimum operating conditions. In this program we apply the ultrasonic thermometry in 2 areas; 1) fuel temperature measurements in the manifold region and 2) fuel temperature in one of the combustor cooling passages. As a by-product of cooling passage measurement we will also measure heat flux and surface temperature of material between the combustion inner chamber and cooling channel. BENEFIT: Ultrasonic thermometry offers unique capabilities to hypersonic vehicle development. Improved thermal transport measurement methods speed development, improve understanding, and enhance our ability to validate analytical models and hardware for numerous propulsion and aeroshell applications. The non-intrusive nature of the method is particularly attractive for hostile environment encountered in hypersonic flight. The immediate market for this technology is primarily in military applications where there is a need for improved thermal transfer measurement tools to drive the development and evaluation of hypersonic materials and components. In addition to the applications in hypersonic vehicle and propulsion systems, the ultrasonic temperature sensor technology has applications in the areas of space lift, space platform, combustion research, and missiles. There is also a potential commercial market in areas where thermal transport data is needed in relatively inaccessible regions such as combustion chambers, reactors and in some glass molding operations.