パラフィン模型による任意形状農産物の有効温度伝導率の測定について

抄録

For the purpose of measuring the effective the-rural diffusivity of anomalously farm products, the paraffin-wax-model method in comparing the
coolin curves of the farm products and that of itis paraffin-wax model, was used.
The diffusivity is calcuated using the following equation:
κ_o=κ_pm_o/mp (1)
where κ_o: the effective thermal diffusivtiy of the farm product.
κ_p: the thermal diffusivity of the paraffin wax.
m_o: the slope of a plot of the logarithm of the temperature against the time of the cooling curve of the product for the condition of negligible surface thermal resistance.
m_p: The slope of a plot of the logarithm of the temperature against the time of the cooling curve of the paraffin-wax model for the condition of negligible surface thermal resistance.
The equation is correct for the condition of negligible surface thermal resitance because the eigenvalue of the Fourier series solution of Fourier heat conduction equation is only the function of the geometrical shape and the slope is the pro-duct of the eigenvalue by the thermal diffusivity.
The measuring procedure is as follows:
1) The product is immersed into the agitated ice-water bath and the temperature of the product near the center is measured and recorded with a recorder employing C-C thermocoupls.
2) The paraffin-wax model of the product is made by pouring molten paraffin wax into the mold made with the plaster.
3) The model is immersed into the bath and the temperature near the center is measured and recorded.
4) The effective thermal diffusivity is calculated from the slopes of the cooling curves of the product and it's paraffin-wax model and the known thermal diffusivity of the paraffin wax using the equation(1).
By this method, the effective thermal diffusivities of Egg (Gifu-Jitori), Egg (Leghorn), Onion, Carrot and Eggplant were determined.