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【期刊论文】Enhancement of Near Wall Mixing of an Impinging Jet By Means of a Bump on the Wall
苏万华, Wanhua Su, Rongwen Lin, Hui Xie and Shao-xi Shi
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-1年11月30日
It is found that a thin and rich mixture layer on a wall is formed after impingement of a gas jet of fuel on the wall. The measured thickness of the mixture layer is about 2mm. and its dispersion rate after the end of injection is much lower, compared to that of a space gas jet. This phenomenon in a small D.I. diesel engine is known as "wall setting" or "wall fuel accumulation" which has an important influence on engine fuel consumption and emissions. This paper presents a technique for enhancing the near wall mixing of an impinging jet by means of a bump on the wall. The development of a wall jet formed after an impingement of a gas jet has been investigated by simultaneously measuring the near wall velocity and concentration distribution. It has been found that a wall jet is stripped off the wall and ejected as a secondary-jet when the wall jet encounters a bump of the wall. Effects of the bump height, the location of the 'bump and the impingement angle are studied at a number of-typical conditions. The distributions of velocity and concentration of a secondary jet are also investigated in detail and the non-dimensional distributions for velocity and concentration of a secondary jet are derived based on the data statistics. In addition, the concept of concentration mean dispersion rate is employed in data processing in order to understand the effects of the bump geometry on mixing rate. It has experimentally confirmed that a controllable mixing process of "space-wall-space" for an impinging jet may be realized by means of a bump setting on the wall.
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苏万华, 张晓宇, 裴毅强, 赵昌普, 林铁坚, 赵华
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-1年11月30日
用CFD数值模拟方法研究了一种新型燃烧室设计——BUMP燃烧室对直喷柴油机喷雾燃烧过程的影响。模拟表明,bump环扰动缸内气流运动产生复杂的流谱,形成强烈的湍流,强化燃油与空气的湍流混合速度。此外,燃油喷雾撞壁后,bump环剥离壁面射流形成二次空间射流,减少了燃油在燃烧室壁面的沉积,湍流混合速率大大增加,燃烧过程得到明显改善。数值模拟解释了BUMP燃烧室在不增加燃油消耗的情况下获得低排放的实验现象。
均质充量压燃, 燃烧室, 混合气形成, CFD, 数值模拟
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【期刊论文】气口顺序喷射、稀燃、全电控柴油/天然气双燃料发动机的研究1
苏万华, 林志强, 汪洋, 谢辉, 王江, 裴毅强, 费向阳, 刘文胜, 李红珍, 王根生
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-1年11月30日
采用气口顺序喷射、稀燃、全电控柴油/天然气双燃料发动机方案,对斯太尔WD615.64增压非中冷柴油机进行了改装。实验结果表明,改装后的发动机NOx、颗粒和NMHC排放均达到了欧II排放指标。CO和HC(含甲烷)可以通过后处理解决。
双燃料发动机, 稀燃, 电子控制
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