Mohammed Khalil Ibrahim

This paper describes a new pressure measurement technique for measuring the pressure over rotating blades of an industrial axial flow fan. The new technique is called the pressure sensitive foil (PS-Foil) technique. In this technique, a very thin aluminum foil is coated with pressure sensitive paint using anodization. The resulting PS-Foil can be stuck on any blade using a very thin layer of silicon. The PS-Foil technique shows a very fast time response like conventional porous anodized aluminum and can be applied to any rotor blade without fabricating the blade from aluminum. The total thickness of the aluminum foil and silicon layer is as small as 200 μm. An intensity based method and prior calibration procedures are used to obtain the calibrated PSP image. The unsteady experimental setup presented here shows that the PS-Foil time response is on the order 30 μs which is close to the conventional porous anodized aluminum method. Two applications are considered here to assess the applicability of this technique. Subsonic jet-plate impingement, and rotating blade of industrial fan. The pressure distribution over the impingement plate at different plate angles, and over the rotating blade at various speeds could be obtained with sufficient spatial resolution.

The mechanical vibration is applied to a spacecraft via the interface to a launch vehicle at lift-off. The spacecraft is also exposed to acoustic pressure with wide frequency range. Lightweight and large area structures, such as solar paddles, antennas, and components with relatively high natural frequencies, are sensitive to acoustic load. Although the acoustic tests are usually conducted for components and system of the spacecraft, acoustic tests and analysis of the spacecraft mounted in a fairing have not been sufficiently done. It is expected that numerical analysis can be applied to the prediction of acoustic environment inside of fairings. Japan Aerospace Exploration Agency (JAXA) has been developing a vibroacoustic prediction tool by the wave based method (WBM), which is one of the deterministic approaches and is proposed for numerical prediction up to the mid-frequency range. The existing deterministic approaches can not accurately solve vibroacoustic problems in this range. In this paper, numerical prediction results of sound transmission by the 3D WBM and FEM are compared with those by an experiment, and verification of the 3D WBM is examined.