Temperature measurement using acoustic reflectors

In this paper, we describe temperature measurement using acoustic reflectors. The reflectors increased the number of sound paths to five. The temperature distribution was measured with one loud speaker (SP) and one microphone (MIC) utilizing a radial transmission of the SP and specular reflections of sounds. The propagation paths of the sounds could be used as the sound probes and their directions could be changed using the acoustic reflectors with plane surfaces. By adjusting the angles of the acoustic reflectors as the propagation paths reached one of the MICs, the temperature distribution of an arbitrary and partial space in the measurement object could be measured. The temperature distribution of a horizontal space partitioned into five unit cells was measured with one SP, one MIC and ten acoustic reflectors. The -6dB beam width of the SP was approximately 80deg, thus the received signals maintained sufficient amplitudes. Experimental results showed a good agreement with the temperature distribution results measured with thermocouples.