A new approach for calibration of hot-wires is proposed, which simplifies the calibration procedure and reduces the tunnel run-time by an order of magnitude. In supersonic and hypersonic flows it is generally accepted that the velocity and density sensitivities are equal. Thus the direct measurable quantities are only mass flow, m, and total temperature, To. Very few supersonic facilities have the capability of varying To over an adequate range. However, if overheat parameter aw is used to calibrate the hot-wire, then directly measurable quantity, voltage, will be a function of mass flow, overheat parameter and wire temperature i.e., , where aw contains the needed total temperature information. In this innovation, the feasibility of calibrating 2-wire probe using CTA with functional relationship in supersonic/hypersonic flows will be shown. The advantage of using aw instead of To is that it is not necessary to know the recovery factor, , and coefficients in wire resistance to temperature relationship, and , for a given probe during calibration. This technique will provide the most accurate calibration procedure for hot wire probes and it will be possible to obtain accurate temperature fluctuation information. Other conventional methods would require additional measurements to get the required information.
Potential Commercial Applications: The technique simplifies the calibration process of hot-wires, significantly reducing the run- time and test matrix required to conduct calibration tests. The proposed innovation has potential application in atmospheric wind tunnels, where there is no ability to obtain any temperature sensitivity information at present.
