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申論題資訊

試卷:110年 - 110 國立清華大學碩士班考試入學試題_工程與系統科學系/乙組:熱力學#105638
科目:研究所、轉學考(插大)◆熱力學
年份:110年
排序:0

題組內容

Problem 3. Assume that you are a thermal engineer working for a cryogenics company. Your project is to design the operational parameters for controlling fluid mixture (liquidand gas) temperature that is cooled by ice cubes in an insulated container. To help you to conduct this project successfully, the following questions are to be answered (20%; 10 pts each):
 

申論題內容

Q2. The project is based on a problem that an insulated container is partially filled with a liquid in gas at an isothermal condition where the fluid temperature is higher than the ice temperature. Then, several ice cubes are dropped into the container (see the image below). Regarding this transient process of heat transfer, you are asked to develop a formula based on the first law of thermodynamics to predict the needed ice mass or needed ice initial temperature to achieve a targeted final temperature at its thermal equilibrium. Assuming that you know the liquid mass, liquid temperature, gas mass, gas temperature and thermodynamics properties of liquid, gas and ice. To simplify the analysis, let us assume that the mass of gas remains unchanged after the addition of ice to the container and the process of heat transfer in the container is isobaric. To derive a practical cquation for the analysis described herein, how do you make assumptions and simplify the first law of the thermodynamics based on the equation shown in Problem 1-Q2? List the notations for each parameter and variable in the equation proposed by you.
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