Simultaneous Determination of Thermal Conductivity and Thermal Diffusivity of Food and Agricultural Materials Using a Transient Plane-Source Method

Authors: Huang, Lihan; Liu, Linshu

Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2009
Publication Date: 6/27/2009
Citation: Huang, L., Liu, L.S. 2009. Simultaneous Determination of Thermal Conductivity and Thermal Diffusivity of Food and Agricultural Materials Using a Transient Plane-Source Method. Journal of Food Engineering. 95:179-185.

Interpretive Summary: Thermal conductivity and thermal diffusivity are basic physical properties of food and agricultural materials. They are essential in designing any food engineering processes, particularly for thermal processing of foods. This research developed and validated a new easy-to-use methodology to simultaneously measure thermal conductivity and thermal diffusivity of selected food and agricultural materials. The methodology developed in this study can be used by scientists and engineers to directly measure these two properties and use them in designing food and agricultural engineering processes.

Technical Abstract: Thermal conductivity and thermal diffusivity are two important physical properties essential for designing any food engineering processes. Recently a new transient plane-source method was developed to measure a variety of materials, but its application in foods has not been documented. Therefore, the objective of this work was to evaluate the feasibility of this method for measuring the thermal conductivity and thermal diffusivity of foods. A calibrated probe, constructed with a resistance thermal device, was used to simultaneously measure the thermal conductivity and thermal diffusivity of foods. For standard materials, such as water, mineral oil, ethanol, ethylene glycol, and olive oil, the measured thermal conductivity and thermal diffusivity of these materials were generally within 0.5 – 10% from the standard values in the literature. For food materials such as beef, chicken, flour, and apple, the measured values were within 0.2 to 15% of the thermal conductivity and thermal diffusivity of the same material reported in the literature. The results of this study suggest the transient plane-source method is an accurate method for simultaneously measuring thermal conductivity and thermal diffusivity of foods.