Tomohiro Kameya

Unsteady pressure-sensitive paint measurement based on the heterodyne method using low frame rate camera.

The pressure-sensitive paint technique based on the heterodyne method was proposed for the precise pressure measurement of unsteady flow fields. This measurement is realized by detecting the beat signal that results from interference between a modulating illumination light source and a pressure fluctuation. The beat signal is captured by a camera with a considerably lower frame rate than the frequency of the pressure fluctuation. By carefully adjusting the frequency of the light and the camera frame rate, the signal at the frequency of interest is detected, while the noise signals at other frequencies are eliminated. To demonstrate the proposed method, we measured the pressure fluctuations in a resonance tube at the fundamental, second, and third harmonics. The pressure fluctuation distributions were successfully obtained and were consistent with measurements from a pressure transducer. The proposed method is a useful technique for measuring unsteady phenomena.

Combined pressure and temperature sensor using pressure- and temperature-sensitive paints

In pressure-sensitive paint (PSP) measurements, pressure is deduced from the luminescence intensity of PSP. Since the intensity depends not only on pressure but also on temperature, PSP results have to be compensated by the surface temperature; thus, we combined temperature-sensitive paint (TSP) with PSP for the compensation. PtTFPP and CdSe/ZnS were adopted as pressure and temperature sensitive luminophores, respectively. In this paper, we report the pressure and temperature sensitivities and the photostability of the combined sensor around an atmospheric pressure and room temperature.

Pressure-Sensitive Paint Measurement on Co-Rotating Disks

There appears fluttering phenomena in a hard disk drive system with high-speed disks rotating inside a closed space, leading to degrade of reading and writing performance. The precise pressure distribution on the disk may improve the performance, but there has been no report because it is very hard to measure the surface pressure using conventional techniques, such as pressure taps. While pressure sensitive paint (PSP) seems to be suitable for the pressure measurement on the disk, we have to compensate its highly temperature-sensitive characteristics of PSP, because the temperature distribution on the disk is not assumed to be uniform. We employed PySO3 H based PSP, which has small temperature sensitivity, and have obtained the pressure distribution on the disk rotated at various speeds (10000–20000 rpm) successfully. The result showed that the pressure is higher at the disk outside than at the center, and forms a concentric circle distribution. Moreover, we found that the pressure difference between the inner and outer region of the disk increases as a square of disk rotation speed.Copyright