研究报告标准格式.doc

聖約翰技術學院專題研究 題目：排氣櫃氣流特性量測與分析 單位：機械系 職級：副教授 姓名：吳順治 日期：民國92年12月31日 摘 要 近年來，化學相關實驗室或工廠陸續設置排氣櫃，其中尤以研發與檢驗部門數量最多。、 關鍵詞：排氣櫃、風速量測、自動調速系統 Abstract The demand of fume hoods to local chemical laboratories and factories is increasing, especially for RD and quality control departments. A fume hood is classified as an enclosed ventilation hood with inner space where bottled chemicals and experimental devices are stored. The opening of a fume hood is necessary for manual operation, while a sash with transparent window in front of a fume hood adjusts the size of the opening. Fresh air is drafted into the opening of a fume hood to drive airborne contaminants toward downstream piping connecting to the air cleaner (scrubber, HEPA filter, etc.). The cleaned air then goes through the fan and is released in outdoors atmosphere. Safety issues form the basis to fume hood design concepts, since health of the worker next to a fume hood can only be protected when polluted air inside the fume hood is removed effectively. A well-designed fume hood satisfies the following criteria: 1. Velocity distribution on the hood opening is as uniform as possible with an average inward speed kept at around 0.5 m/s. 2. Curl phenomenon inside the fume hood is weakened or avoided. 3. Volumetric flow rate of supplementary fresh air is automatically adjusted to fit the size of the opening. The criteria mentioned above are all parameters to flowfield characteric inside the hood, in which the inward velocity distribution on the hood opening is most often applied since it is convienent to be measured. Average inward speed of fresh air can neither be too slow (air contaminants could leak to indoor space) nor too fast (curl phenomenon can cause reverse airflow on the hood opening). At the present time domestic scholars haven’t investigated a clear and simple measure of evaluating the velocity distribution on the opening of a fume hood yet, leaving a wide range for further experiments and in