Arcjet facility control and health monitoring using noninvasive diagnostics with response surface paradigm

OKSI proposes to implement a set of noninvasive optical diagnostics combined with a simple arcjet response surface model to provide real-time feed back control to the operator to control current and mass flow rates to affect the desired flow conditions. Under Phase-I, OKSI will demonstrate high spectral resolution emission measurements at the AEDC arcjet. Measurements will be conducted at several set points that encompass the range of arcjet operating conditions. In addition, high fidelity non-equilibrium kinetics thermochemical model will be run at the same conditions as the measurements. Model predictions combined with measurements will be used to create a response surface that expresses the measured flow quantities (e.g., in-band total radiation, or radiation associated with a specific transition) as a function of the controlled input parameters (e.g., current, voltage, and mass flow rates). Under Phase-II, the methodology will be expanded to additional noninvasive diagnostics and monitoring sensors (e.g., key species profiles from which total enthalpy, or radial profiles, can be obtained), and additional input parameters. The response surface may be implemented as a look up table that can rapidly provide to the operator the proper adjustments to the arcjet controls. If successful, the control loop can be automated to run a very stable arcjet without a man in the loop. The same diagnostics will provide health monitoring capabilities alerting the operator in case certain species (e.g., Cu) indicative to excess erosion or facility damage appear in the flow.