A Pressure Measuring System Using Electronically Scanned Pressure Sensors (ESP) Installed in a Transonic Blowdown Wind Tunnel

A pressure measuring system using electrically scanned pressure sensors (ESP) was built and installed in a transonic blowdown wind tunnel, and thoroughly tested to see how effective an ESP system is in enhancing data productivity when compared with the scanivalve system hitherto used. After a brief description of what an ESP is and how to use it, detailed results are given of studies in which linearity, stability and repeatability characteristics of our ESP system was examined. It is shown that the deviation of the system output from linearity is less than 0.25％ of the full-scale value (FS), that the thermal zero shift is of negligible magnitude (less than a quarter of 0.1％ of FS) and that the repeatability is also quite satisfactory. The pressure sensors were placed in the plenum chamber surrounding the test section, where the temperature change during the tunnel operation remains rather small (generally about 1C). This environmental stability contributed to the excellent performance of our pressure measuring system. The time needed for the measurements of pressures on and about an airfoil model (42 static pressures on the surface and 35 total pressures in the wake) is 8 seconds whereas it has been 43 seconds with the Former scanivalve system. The data transfer time continues to be disproportionate - 35 seconds - as long as the data processing unit is unchanged. Thus, concurrent improvement in the data processing unit is necessary if the maximum benefit is to be obtained from the installation of an ESP system.
資料番号: NALTR0883000
レポート番号: NAL TR-883