Electronically scanned pressure measurement scanner for cryogenicwind tunnel applications

摘要

Electronically scanned pressure (ESP) measurement modules are usedin wind tunnels to measure surface pressures on models. Measurementchannels are connected to pressure ports through small diameter tubing.Use of current state-of-the art ESP scanners in cryogenic wind tunnelshas led to several practical problems which contribute to additionalexpense and loss of data quality. First current use of ESP scanners incryogenic wind tunnels (at room temperature to below -25° C)dictates the need for protection against the thermal environment. Thecurrent solution is the use of a heater box which causes a number ofoperational problems. The installation of the heater box istime-consuming and labor-intensive. Its size reduces the amount of spaceavailable for scanner installation. Secondly, a wind tunnel test must beinterrupted for on-line calibration which consumes as much as 15% of thetotal test time. Finally, the pressure and balance measurements aretaken in separate runs because of an “apparent strain”problem. An electronically scanned pressure measurement module capableof operating directly in a cryogenic environment has been developed andtested over an extended temperature span. Total uncertainty, which ismeasured at less than 0.1% of FSO at 1 atmospheric reference pressurewill be discussed