Two-dimensional Interferometric Temperature Sensor

Southwest Sciences proposes to apply a novel, yet simple non-invasive technique, Point Diffraction Interferometry (PDI), to provide highly accurate and precise two-dimensional temperature profiles. This proposed instrument can provide reliable and robust temperature measurements that are required for propulsion test operations, including facility and test article health monitoring. Unlike invasive techniques, such as thermocouples which only provide point data measurements, a PDI system produces two-dimensional temperature profiles without disturbing the test flow field. Other non-invasive techniques could be used, however, many only provide point measurements or one-dimensional profiles, are optically complex, or involve a nonlinear analysis. PDI is a self-referencing technique, inherently stable, and relatively insensitive to vibration. We expect to achieve temperature uncertainties less than 20 K at propulsion exhaust temperatures. This technique uses visible light, simple optics and is easy to align and operate; collimated light sources and imaging detectors in the visible are inexpensive and commercially available.