應用熱傳遞逆問題分析於食品解凍時之熱性質推估

Abstract

食品的熱物理性質與冷凍、解凍過程中的表面對流熱傳係數是影響冷凍速率與食品品質最重要的因素。本論文的研究目的為利用焓值法建立魚肉解凍過程的數學模式以及熱傳遞逆問題的分析理論，估測食品的熱物理性質。使用有限差分法中的顯明法與隱含法成功模擬魚肉的解凍溫度曲線，且皆可由Lavenberg－Marquadt method與Conjugate gradient method求解與實驗量測值相符之表面對流熱傳係數以及解凍過程中魚肉的焓值曲線變化過程。

Thermal properties of materials and surface convection coefficient during freezing or thawing process are the most important factors that influence process rate and qualities of frozen food. The aim of this study is to build mathematical model of thawing process of frozen fish by enthalpy method and use inverse heat transfer problem to estimate its thermal physical properties. In the study, the thawing curve of fish obtained by the explicit and the implicit finite difference methods were accomplished, and by the use of Lavenberg-Marquardt method and Conjugate gradient method the most fitting surface convection coefficient and enthalpy of frozen fish during process could obtain and both methods worked equally well.