Flame Temperature and Soot Characteristics of Diesel Combustion at Different Altitudes
-
摘要:为了研究海拔条件对柴油机冷起动阶段柴油燃烧过程的影响,在定容燃烧弹台架上模拟了平原和海拔2000 m工况下柴油机缸内的热力学状态,利用双色法获取了不同工况下柴油火焰温度和表征碳烟浓度的 KL因子分布. 结果表明,随着海拔由0 m增加至2000 m,环境温度、压力同时降低产生了耦合作用,导致柴油滞燃期由2.0 ms增大至3.13 ms.海拔升高后,柴油燃烧过程中平均火焰温度降低,局部高温区域消失, KL因子总量减少. 海拔条件变化影响了碳烟特性和火焰温度的关系. 随着海拔升高,火焰温度降低,导致碳烟氧化主导阶段碳烟氧化速率降低,局部火焰温度对局部碳烟浓度的影响减小.Abstract:To study the altitude effects on the diesel combustion process under cold-start condition, the thermodynamic state of the diesel engine cylinder was simulated in a constant volume combustion chamber under the plain condition and the 2000 m altitude condition. Flame temperature and KLfactor distribution for soot concentration characterizing were obtained by the two-color method under different conditions. Results show that the simultaneous decrease of ambient temperature and pressure can produce a coupling effect, resulting in the diesel ignition delay from 2.0 ms to 3.13 ms increasing, when the altitude increases from 0 m to 2000 m. As the altitude increases, the average flame temperature decreases during the diesel combustion process, while the local high temperature area disappears and the total KLfactor decreases. The relationship between soot characteristics and flame temperature is affected evidently with altitude increases. With the increase of altitude and the decrease of flame temperature, the soot oxidation rate decreases in the soot oxidation dominated process and the impact of local flame temperature on local soot concentration weakens.
-
Key words:
- diesel engine/
- combustion/
- two-color method/
- flame temperature/
- soot characteristics/
- altitude
-
表 1试验工况
Table 1.Test conditions
试验参数 数值 环境温度Tam/K 815/840 绝对环境压力pam/MPa 2.7/3.1/3.4 冷却水温度Tc/K 293 喷嘴孔径d0/mm 0.16 喷射压力Pinj/MPa 60 喷油持续期tinj/ms 2.7 表 2工况表
Table 2.Condition table
工况序号 Tam/K pam/MPa 对应海拔/m a 840 3.4 0 b 815 3.4 c 840 2.7 d 815 2.7 2000 -
[1] YAN J, GAO S, ZHAO W, et al. Study of combustion and emission characteristics of a diesel engine fueled with diesel, butanol-diesel and hexanol-diesel mixtures under low intake pressure conditions[J]. Energy Conversion and Management, 2021, 243: 114273.doi:10.1016/j.enconman.2021.114273 [2] 高建兵, 马朝臣, 邢世凯, 等. 装有等离子体装置的柴油机颗粒物的氧化特性[J]. bob手机在线登陆学报, 2017, 37(5): 446 − 450+496.doi:10.15918/j.tbit1001-0645.2017.05.002GAO Jianbing, MA Chaochen, XING Shikai, et al. Thermo-gravimetric characteristics of particulate matter emitted from a diesel engine equipped with a non-thermal plasma equipment[J]. Transactions of Beijing Institute of Technology, 2017, 37(5): 446 − 450+496. (in Chinese)doi:10.15918/j.tbit1001-0645.2017.05.002 [3] 高建兵, 马朝臣, 邢世凯, 等. 经过预处理后柴油机颗粒物氧化活性的变化[J]. bob手机在线登陆学报, 2017, 37(9): 913 − 918.doi:10.15918/j.tbit1001-0645.2017.09.006GAO Jianbing, MA Chaochen, XING Shikai, et al. Oxidation reactivity changes of diesel particulate matter after being pre-treated[J]. Transactions of Beijing Institute of Technology, 2017, 37(9): 913 − 918. (in Chinese)doi:10.15918/j.tbit1001-0645.2017.09.006 [4] PICKETT L M, SIEBERS D L. Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure[J]. Combustion and Flame, 2004, 138(1): 114 − 135. [5] 黄胜, 郑高翔, 黄荣华, 等. 海拔对柴油喷雾和附壁燃烧过程的影响[J]. 内燃机学报, 2019, 37(6): 522 − 528.doi:10.16236/j.cnki.nrjxb.201906067HUANG Sheng, ZHENG Gaoxiang, HUANG Ronghua, et al. Influence of altitude on diesel oil spray impingement and attaching wall combustion[J]. Transactions of CSICE, 2019, 37(6): 522 − 528. (in Chinese)doi:10.16236/j.cnki.nrjxb.201906067 [6] 颜方沁, 成晓北, 邱亮, 等. 多点同步采样测量柴油喷雾火焰中的碳烟形貌分布[J]. 燃烧科学与技术, 2018, 24(1): 67 − 74.YAN Fangqin, CHENG Xiaobei, QIU Liang, et al. Soot morphology distribution in diesel spray flame via multi-point synchronous sampling[J]. Journal of Combustion Science and Technology, 2018, 24(1): 67 − 74. (in Chinese) [7] 胡宗杰, 张骏捷, 高宇, 等. 波长积分双色法及其测温精度分析[J]. 工程热物理学报, 2020, 41(7): 1808 − 1819.HU Zongjie, ZHANG Junjie, GAO Yu, et al. Wavelength integration two-color method and its temperature measurement accuracy analysis[J]. Journal of Engineering Thermophysics, 2020, 41(7): 1808 − 1819. (in Chinese) [8] ZHU J, KUTI O A, NISHIDA K. Effects of injection pressure and ambient gas density on fuel-ambient gas mixing and combustion characteristics of D. I. diesel spray [R]. Detroit, USA: SAE, 2011: 2011-01-1819. [9] YANG K, NISHIDA K, YAMAKAWA H. Effect of split injection ratio on combustion process of diesel spray into two-dimensional piston cavity[J]. Fuel, 2020, 260: 116316.doi:10.1016/j.fuel.2019.116316 [10] 何旭, 徐一凡, 王路, 等. 柴油温度对燃烧火焰温度和碳烟生成的影响[J]. 内燃机学报, 2021, 39(2): 97 − 105.doi:10.16236/j.cnki.nrjxb.202102013HE Xu, XU Yifan, WANG Lu, et al. Influence of diesel temperature on combustion flame temperature and soot formation characteristics[J]. Transactions of CSICE, 2021, 39(2): 97 − 105. (in Chinese)doi:10.16236/j.cnki.nrjxb.202102013 [11] KAN Zechao, HU Zhiyuan, LOU Diming, et al. Effects of altitude on combustion and ignition characteristics of speed-up period during cold start in a diesel engine[J]. Energy, 2018, 150: 164 − 175.doi:10.1016/j.energy.2017.12.103 [12] LIU Fushui, SHI Zhongjie, ZHANG Zheng, et al. Numerical study on critical ambient temperature for auto-ignition of the diesel spray under cold-start conditions[J]. Fuel, 2019, 258: 116191.doi:10.1016/j.fuel.2019.116191 [13] MICHELSEN H A. Probing soot formation, chemical and physical evolution, and oxidation: A review of in situ diagnostic techniques and needs[J]. Proceedings of the Combustion Institute, 2017, 36(1): 717 − 735.doi:10.1016/j.proci.2016.08.027 [14] 何旭, 张志鹏, 吴昊, 等. 基于二维激光诱导炽光法的棉籽油扩散火焰碳烟生成特性[J]. bob手机在线登陆学报, 2019, 39(3): 235 − 240+326.doi:10.15918/j.tbit1001-0645.2019.03.003HE Xu, ZHANG Zhipeng, WU Hao, et al. Investigation on the soot formation of cottonseed oil diffusion flame by two-dimensional laser induced incandescence[J]. Transactions of Beijing Institute of Technology, 2019, 39(3): 235 − 240+326. (in Chinese)doi:10.15918/j.tbit1001-0645.2019.03.003 [15] XUAN T, DESANTES J M, PASTOR J V, et al. Soot temperature characterization of spray a flames by combined extinction and radiation methodology[J]. Combustion and Flame, 2019, 204: 290 − 303.doi:10.1016/j.combustflame.2019.03.023