碩士 / 國立中興大學 / 機械工程學系所 / 100 / This study is to analyze the heat transfer performance of fins of a Wankel engine. Comparisons were made for two different types of fins with the calculation of theoretical model and numerical simulation for the actual dimension of a real Wankel engine.
Temperature variations of burned gas inside the cylinder were obtained with the measured pressure data as well as the volume variations of the engine. The estimated gas temperature was then used to calculate the heat transfer rate inside the cylinder wall which was in turn used to find the required heat transfer coefficient outside the cylinder wall in order to maintain the wall temperature below a specified value.
The whole engine case was divided into 36 parts in this study, and the averaged heating load was evaluated for each part with the estimated gas temperature. It was found that if the wall temperature was to be kept below 200℃, an array of fins is required to mount on the surface outside the cylinder wall. If rectangular fins were used, the longest one was 3.46cm. If triangle type fins were chosen, the longest one would be 4.55cm. It seems that triangle fins occupy more space. However, it can save 34% of weight due to less material is used.
The effect of conduction along cylinder wall on the wall temperature was also investigated in this study. It was found that the maximum wall temperature would be 29℃lower if conduction was considered.
Furthermore, a net type of fin was also considered in this study which was constructed by connecting vertical fins with horizontal fins on the top. It was found that the use of fin net may cool down the wall temperature about 12℃. It appears that the net type fin can enhance the heat transfer effort.
| Identifer | oai:union.ndltd.org:TW/100NCHU5311093 |
| Date | January 2012 |
| Creators | Shih-Chen Liu, 劉士誠 |
| Contributors | Jau-Huai Lu, 盧昭暉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 74 |
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