Department of Mechanical Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore, 575 025, India.
Environ Sci Pollut Res Int. 2017 Oct;24(29):23351-23362. doi: 10.1007/s11356-017-9956-7. Epub 2017 Aug 25.
Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~ 4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NO), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NO, and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel.
氮氧化物和烟雾是柴油机的主要排放物。含氧水平较高的燃料由于烟尘的氧化更好，因此排放的烟雾较少。本文的目的是评估使用含氧燃料（即正丁醇及其与纯柴油的混合物）的潜力，混合比例为 0 至 30%（按体积计）。使用现代双缸、四冲程、共轨式直喷（CRDI）发动机，进行了实验和计算流体动力学（CFD）模拟，以估算不同喷油正时（9°、12°、15°和 18°）下正丁醇-柴油混合物的性能、燃烧和废气排放特性。实验结果表明，与纯柴油（Bu0）相比，正丁醇-柴油混合物的 10%（Bu10）、20%（Bu20）和 30%（Bu30）的制动热效率（BTE）分别提高了约 4.5%、6%和 8%。Bu0 的最大 BTE 为 38.4%，在 12° BTDC 时获得；然而，Bu10、Bu20 和 Bu30 分别在 15° BTDC 时达到 40.19%、40.9%和 41.7%。正丁醇-柴油混合物的较高火焰速度在预混阶段燃烧大量燃料，从而改善了燃烧和排放特性。对所有燃料混合物进行了 CFD 和实验结果的比较和验证，以评估缸内压力和氮氧化物（NO），结果吻合良好。实验和模拟结果均表明，随着柴油中正丁醇比例的增加，烟雾不透明度、NO 和一氧化碳排放量均有所降低。
