| Summary: | 碩士 === 中原大學 === 土木工程研究所 === 106 === In this study, we used computational fluid dynamics software, ANSYS Fluent, to simulate the effects of temperature change inside the liquid canned food (Cream of Potato Soup) during the heating process. The slowest heating zone (SHZ) formed by the phenomenon of natural convection caused by the influence of gravity and heat conduction was observed. The numerical model was verified by measured data with the same conditions set-up in experiments.
First, the method of heat sterilization used in the experiment is Pasteurization. Liquid canned food submerged in water was heated in a tank to maintain the temperature at 65℃ in the experiment. The numerical simulation was carried out under the same conditions, and the results were compared to prove the accuracy of numerical simulation. Second, we used CFD software to simulate heat sterilization with different placements, rotation speed and shapes of liquid canned food, cylindrical can was placed horizontally and vertically, the condition of rotation speed was simulated at stationary, 5, 10 and 20 rpm, there were different shapes of liquid canned food such as cylindrical, milk carton, cube and elliptical column. Then, we observed internal temperature changes and distribution of the slowest heating zone.
According to the results of numerical simulation, it is found that when the cans were at stationary, the cylindrical can placed horizontally had higher heating efficiency than the one placed vertically. We also found that the elliptical column cans had the largest surface area and the highest heating efficiency. When the cans were rotated, we found that the heating efficiency of cans were improved for each shape, but the heating efficiency of the elliptical column can with the largest surface area was not the highest. Thus, the increase of surface area and rotation speed can increase the heating efficiency. However, the proper shape of liquid canned food could achieve the best bactericidal effect.
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