Experimental studies on the dual-fuel sequential combustion and emission simulation
Experimental studies on the dual-fuel sequential combustion and emission simulation
复制标题
双燃料顺序燃烧及排放模拟实验研究
DOI：
10.1016/j.energy.2013.01.026
复制
发表时间：
2013-03
期刊：
影响因子：
9
通讯作者：
Huang Zhen
中科院分区：
文献类型：
--
作者：
Yang Zheng;Han Dong;Huang Chen;Huang Zhen
这项研究从理论上提出并通过实验证明了在单缸发动机上使用一种新颖的燃烧模式（双燃料顺序燃烧）DFSC 可以同时减少氮氧化物和烟尘。 DFSC 通过在进气口喷射高十六烷值燃料（本研究中使用正庚烷），然后在上止点 (TDC) 附近直接喷射高辛烷值燃料（本研究中使用乙醇、异丙醇、1-丁醇和异辛烷），将混合良好的稀薄燃油/空气混合物引入气缸。本研究采用DFSC模式运行四种燃料组合（正庚烷/异辛烷、正庚烷/乙醇、正庚烷/异丙醇和正庚烷/1-丁醇），并研究了每种燃料组合的点火机理和燃烧过程。观察到直喷燃料的三种燃烧模式：活性气氛主导点火、活性热气氛主导点火和热气氛主导点火。直接喷射燃料的点火正时很大程度上取决于预混合的正庚烷浓度，并且轻微地受到增压冷却效果的影响。在目前的测试条件下，正庚烷/乙醇 DFSC 在最大指示（平均有效压力）IMEP 0.76 MPa 下几乎无烟且超低 NOx 排放。为了加深对这种燃烧模式下 HC 和 CO 排放形成机制的了解，采用三维（计算流体动力学）CFD 结合简化的化学动力学机制来模拟正庚烷/异辛烷 DFSC 模式。初步结果表明，HC排放主要来源于喷射流的核心区域，该区域的燃油喷射尖端无法充分氧化和燃烧。 CO 排放主要产生于气缸壁、活塞环缝隙区域和燃烧室碗的边界层。
This study theoretically proposes and experimentally demonstrates the simultaneous reductions of NOx and soot using a novel combustion mode, (dual-fuel sequential combustion) DFSC, on a single-cylinder engine. DFSC introduces a well-mixed, lean fuel/air mixture into the cylinder by injecting high-cetane number fuel (n-heptane was used in this study) at the intake port followed by the direct injection of a high-octane number fuel (ethanol, iso-propanol, 1-butanol and iso-octane were used in this study) near the top dead center (TDC). Four fuel combinations (n-heptane/iso-octane, n-heptane/ethanol, n-heptane/iso-propanol, and n-heptane/1-butanol) were operated with the DFSC mode in this study, and the ignition mechanism and combustion processes of each fuel combination were investigated. Three types of burn modes of directly injected fuels were observed: active atmosphere-dominated ignition, active-thermal atmosphere-dominated ignition, and thermal atmosphere-dominated ignition. The ignition timings of the directly injected fuels were strongly dependent on the premixed n-heptane concentration and were slightly influenced by the charge cooling effects. In the present testing conditions, the n-heptane/ethanol DFSC showed almost smokeless and ultra-low NOx emissions at the maximum indicated (mean effective pressure) IMEP of 0.76 MPa. To increase understanding of the formation mechanisms of the HC and CO emissions in this combustion mode, three-dimensional (computational fluid dynamics) CFD coupled with reduced chemical kinetic mechanisms was used to simulate the n-heptane/iso-octane DFSC mode. Preliminary results show that the HC emissions originate primarily from the core region of the spray jet, where the fuel injection tip was unable to fully oxidize and burn. The CO emissions produce primarily at the boundary layer of the cylinder wall, piston ring crevice region, and combustion chamber bowl.
登录
查看更多内容
影响因子：
9
作者：
H. Machrafi;S. Cavadias;J. Amouroux
通讯作者：
H. Machrafi;S. Cavadias;J. Amouroux
影响因子：
4.4
作者：
Rui Wang;P. Cadman
通讯作者：
Rui Wang;P. Cadman
影响因子：
4.4
作者：
J. Clarkson;J. Griffiths;J. Macnamara;B. J. Whitaker
通讯作者：
J. Clarkson;J. Griffiths;J. Macnamara;B. J. Whitaker
影响因子：
4.4
作者：
R. Lockett;R. Woolley
通讯作者：
R. Lockett;R. Woolley
影响因子：
11.2
作者：
N. Komninos
通讯作者：
N. Komninos