食品罐頭之所以能夠保存，是因為施行殺菌作業，但究竟應在多高的溫度
下，保持多長的時間進行殺菌較為適當呢？這就甚為複雜！殺菌的裝置稱
為殺菌釜，殺菌是利用水蒸汽為加熱媒體。重要的殺菌條件是溫度，加熱
時間及壓力，故探討溫度及壓力隨時間變化的情形就相當的重要了。　本
研究先推導出殺菌釜內蒸汽－空氣混合殺菌的數學模式，再進行電腦模擬
以預測殺菌釜內溫度、壓力、蒸氣和空氣質量的變化，並計算所有的熱傳
。結果我們發現進入殺菌釜內的蒸汽壓力和進汽閥的大小對殺菌釜內的溫
度、壓力、蒸汽質量和空氣質量等性質有較大影響；而排氣孔的大小對這
些性質則較無影響。而熱損失大部分來自於凝結水及釜壁。

Long time preservation of canned food is accomp- lished through
sterilization. However, the tem- perature and lasting time of
sterilization are very complex issues. The device for
sterilization is called "RETORT", in which water steam serves
as heating media. The dominating conditions of steri- lizing
are temperature, pressure and heating time, so the responses of
temperature and pressure to time are the most important. The
study first deduced the mathematical medel of the sterilization
of steam- air mixture in retort, then simulated the change of
temperature, pressure and mass of steam and air in retort by
computer and calculated all heat transfer. It is found that
the temperature, pressure and mass of steam and air in the
retort are affected more by pressure of steam into the retort
and the size of the steam valve than by the size of the vent.
The heat loss is mainly through condensation of water and
through walls of the retort.