ABSTRACT
This chapter discusses the three-dimensional acoustic temperature tomography for detecting a hot spot in grain bulk. A hot spot in a grain bulk is a localized high temperature zone and normally spoilage beginning in this location. If a hot spot cannot be found in time, a great loss of grain will occur. Compared with contact method, non-contact method is a better one for hot spot detection in grain bulk, since grain is the poor conductor of heat. The chapter describes the influence of sound transceiver layouts on the reconstruction accuracy of 3D temperature field is investigated for hot spot detection in grain bulk. In grain bulk, sound is propagated principally through the gas in the passageways between the grain kernels. In stored grain, sound is propagated principally through the gas in the narrow passageways between the grain kernels. Propagation through the solid grain matrix appears almost nonexistent because of the friction between the kernels.
