Acoustic measurement of temperature distribution in a room using a small number of transducers

We propose a method for noncontact measurement of room temperature distribu tion using a small number of acoustic transducers. The sound propagation ve locity is dependent on the air temperature; and it is acquired from the tim e of flight of sound. The mean temperature parallel to the sound probe is a cquired using an acoustic delay line consisting of a pair of transducers. T he measured object is a room of size 4,000 mm (D) x 4,200 mm (W) partitione d into a 3 x 3 grid, with 9 unit cells. By at-ranging a certain geometrical property of the sound propagation path, we can formulate an expression for the temperature distribution as a matrix function of the sound velocity. T welve transducers are installed in contact with the four walls. We create a temperature gradient throughout the room using an electrical heat source. Experimental reconstruction results of the room temperature distribution we re in agreement with the distributions estimated from the temperature profi les of the heat sources. This technique has the advantages of noncontact se nsing, quicker response time and simpler calculation of room temperature di stribution, in comparison with conventional temperature measurement systems .