Complementary experiments for parameter estimation in heat transfer model

Abstract

Thermal properties are critical parameters to design and implement efficient thermal processes especially for food manufacturing. Current methods to measure temperature-dependent thermal properties are expensive, time consuming and labor intensive with certain methods requiring composition analysis of food. To solve those problems, a novel method and equipment, named TPCell, was developed to estimate temperature-dependent thermal conductivity in a single experiment. For simultaneous estimation of temperature-dependent thermal conductivity and volumetric heat capacity, a new generation of TPCell was designed with complementary experimental profile and parameters were estimated by analyzing the parameter sensitivity coefficients. For different heating profile, the scaled sensitivity coefficients (SSC) of multiple parameters and optimal values were compared to determine the number of parameters that can be estimated. The thermal properties of sweet potato puree were estimated using sequential parameter estimation. The temperature-dependent thermal conductivity was found as 0.516 ± 0.011 W/mK at 26 °C and 0.798 ± 0.030 W/mK at 135 °C. Also, the volumetric heat capacity in the same temperature range was 3.520 × 106 ± 0.124 × 106 J/m3K. Therefore, the complementary experiment was successful in simultaneous estimation of temperature-dependent thermal conductivity and volumetric heat capacity.