- 學位論文
室內通風設計與改善-以大型引擎實驗室為例
A study on interior design and internal ventilation of engine dyno room
摘要
引擎性能輸出與許多外在環境因素有關，其中引擎的進氣溫度更是決定性能一大因素。身為專業的引擎實驗室更應具備良好通風設計以提高實驗室的價值所在。為使本研究更貼切於實際作業環境，並加入室內作業之法規，一氧化碳最高濃度不得超過9ppm及作業場所溫度不得超過40℃作為全新引擎實驗室積極研究目標。 在本研究裡，透過國外專業引擎實驗室的室內空間作為本次設計大型引擎室內空間為基礎，以開發14坪的坪數作為本次引擎實驗室的室內空間。 本研究使用套裝模擬軟體CFD(Computational Fluid Dynamic)預測，若室內通風設計以引擎進氣量作為室內最少需要的通風量為前提之下，室內將產生急劇的高溫，使室內溫度上升至357K及一氧化碳濃度將超越室內安全法規。透過放大抽氣馬達流量至2倍，即可達成本研究所訂定之目的。然而將抽氣管的流量放大4倍時，與2、6倍相較之下擁有更好的降溫效果。 透過加裝擋板以減少室內排煙氣罩面積，此方法可降低室內最高 溫度3K及降低一氧化碳濃度，但隨著氣罩開口面積縮小，引擎壁面及動力計壁面因對流傳遞出的熱空氣因無法有效進入氣罩，使室內溫度無法完全到達常溫，對此方案改善效果是有限的。 本研究加入氣簾並進行室內溫度之探討，發現若使室內流場速度加快，將造成引擎壁面熱傳遞速率增快，使室內溫度變得更加嚴重。且高速噴流將原先受限於氣罩內部的高溫廢氣推擠至氣罩外，廢氣流竄於室內，隨著室內流速增快，溫度及一氧化碳濃度上升越顯嚴重。
並列摘要
Engine performance are deeply affected by many external factors. Among them all, the air temperature flowing to the engine plays a dominant role. In a professional engine test laboratory, good ventilation should be installed for her better function. In order to make this experiment similar to the practical operation to the maximum and cope with the indoor task regulations, Carbon monoxide less than 9 ppm and lab-temp. No higher than 40 degree Celsius are essential conditions required for the environment of this brand new engine laboratory. In this study by referring to many indoor housing designs of international professional engine laboratories, we built up one 14-square-meter engine laboratory room accordingly as ours. According to CFD(Computational Fluid Dynamic) estimation, the engine inside ventilation designed on the basis of the engine’s air inflow as the minimum quantity will unavoidably lead to the big surge of the engine indoor temperature up to 357K and the exceeding density of Carbon monoxide ( CO ) allowed by the engine indoor safety code. Just by increasing the airflow quantity of the ventilation motor two-time bigger, the goal of our study can be successfully achieved real time. By way of installing the baffle to decrease the engine displacement mask area, engine inside temp, (3K) and CO density can be reduced. However, this also prevents the hot air released by the convection of the engine housing and dynamometer housing from entering the air mask, which disables the engine inside temp. Drop back to the normal one. Obviously, this design does not help much. Out of curiosity, we set up Air Curtain inside and proceeded with this temp. study. It was discovered that to speed up the airflow inside the engine will add to the heat transmission of the engine inside housing and make the temp. higher.; and the high-speed airflow will push the high-temp. waste gas stored inside out of the air mask. Waste gas flows freely inside the engine.The faster the airflow inside the engine circulates, the higher temp. and the denser CO we get.