High-Temperature, MHz-Bandwidth, Miniaturized Heat-Flux Sensors for High-Speed Flows

The Interdisciplinary Consulting Corporation (IC2) proposes to develop high-temperature, high-bandwidth, miniaturized heat flux sensors that are applicable in a variety of environmental conditions such as those encountered in high-speed ground- and flight-test facilities. The proposed sensing system addresses a critically unmet measurement need in NASArsquo;s technology portfolio, specifically the ability to make quantitative, time-resolved, mean and fluctuating heat-flux measurements with sufficient dynamic range, bandwidth, and spatial resolution in high-temperature, high-speed flows using a robust, miniature sensor to facilitate installation in scale models and high-speed ground- and flight-test facilities. The sensor system will enable single-point measurement of heat flux for characterization of complex boundary layer flows in ground-test facilities over a wide range of temperatures, with a target maximum continuous operating temperature gt;1000 K (727 deg;C). The proposed heat-flux sensor consists of a microfabricated thin-film thermopile on top of a support substrate with a thin protective coating and backside electrical connections. This design represents a robust, flush-mounted, miniature, heat-flux sensing system that possesses improved sensor survivability, reduced humidity sensitivity, and less bulky, fragile packaging than existing solutions. The flow disturbance for this sensor is minimal because of the flush-mount design and small footprint. Optimized sensor electronics will also help improve the sensitivity, dynamic range, and bandwidth of the sensor.