直接噴射柴油引擎三維噴霧流場模擬

The Simulation of 3-Dimensional Fuel Injection Spray Flow Field in Direct Injection Diesel Engine

吳中興(Chung-Hsing Wu) ； 呂有豐(Yeou-Feng Lue)

《農業機械學刊》 9卷1期 (2000/03) Pp. 33-43

https://doi.org/10.30062/JAM.200003.0003

摘要

本研究以KIVA-3 CFD程式模擬YANMARL70-AE單缸D.I.柴油引擎，分別模擬燃燒室未噴射燃料及噴射柴油燃料兩種情況，分析比較其流場特性，並探討於小型D.I.柴油引擎燃燒室內噴霧液滴行為及其與流場的相互影響。經由模擬及分析流場速度、氣化密度分佈、流場溫度分佈及噴霧的發展，結果發現活塞內杯對燃燒室流場及噴霧液滴之行為的影響效應相當顯著。它會造成擠壓流動並進而產生強烈的滾轉效應，而於膨脹行程則會產生逆擠壓流動；這些流場特徵有助於燃料蒸發、燃料與空氣混合及燃燒率的提高。另外燃料液滴受到滾轉流場效應的影響，會沿著滾轉流場旋轉方向行進，並被引導且均勻分佈於活塞內杯周緣。

關鍵字

KIVA-3 ； 直接噴射柴油引擎 ； 噴霧

並列摘要

The study focused on the flow field simulation of YANMAR L70-AE single cylinder, direct injection diesel engine, with KIVA-3 code. The flow field characteristics of combustion chamber without fuel injection and with diesel fuel injection were investigated, respectively. We also attempted to understand the behaviors of spray droplet and how the spray interacted with gas flow field in a small D.I. diesel engine combustion chamber environment. We have successfully simulated the flow field and the injection spray of a small D.I. diesel engine, and obtained data from analyzing the velocity of flow field, gas density distribution, gas temperature distribution and spray development in the combustion chamber. The results showed that the bowl in piston was the dominator factor, which affected the spray behaviors of diesel fuel, as well as the flow field development. During the compression stroke, the piston bowl generated squish flow and then induced strong tumble flow. As during expansion stroke, reverse squish flow was the dominant flow. As a result of above flow characteristics, evaporation, mixing, combustion rates within an engine combustion chamber were increased. Tumble flow field also affected the spray droplet behaviors that caused the spray droplet moved along the rotation of tumble flow and then spread uniformly over the piston bowl wall.

並列關鍵字

KIVA-3 ； D.I. diesel engine ； Spray