The observation of phase state and temperature using noninvasive ultrasonic waves.

There are many ways to obtain temperature measurements and observe phase changes, but most rely on physical contact or a line-of-sight path with the material. Many industries ranging from oil and gas to food and beverage could expand their application space in select scenarios if a noninvasive means were available to identify the internal temperature state of a material within a confined vessel. This thesis investigates the hypothesis that the use of ultrasonic signals and the resulting time of flight and intensity of the high-frequency sound wave may be used to identify a material undergoing a phase change within a confined vessel. A wax melting experiment within a confined chamber has been designed to test this hypothesis. The results presented within this work demonstrate the viability of the method and the results for the speed of sound of a material as a function of temperature are highly repeatable and indicate a clear one-to-one ratio between the speed of sound and the temperature state.