Analysis of coaxial injection characteristics of natural gas/diesel dual fuel engine
1. School of Energy and Power Engineering， Jiangsu University， Zhenjiang， Jiangsu 212013， China； 2. Zhenjiang Vocational and Technical College， Zhenjiang， Jiangsu 212016， China
Abstract：The high-speed schlieren method was used to carry out the coaxial injection test of natural gas/diesel dual fuel engine, and the effects of gas injection pressure and environmental pressure on the perimeter variation of three profiles of natural gas injection were analyzed. The numerical simulation was carried out by CFD software, and the natural gas volume fraction and velocity field were analyzed by ENSIGHT software. The results show that the circumference of three profiles of natural gas jet is decreased with the decreasing of natural gas injection pressure and the increasing of ambient pressure, and profile curves of dual fuel injection are more violent than that of single fuel injection. When the head of the natural gas jet meets the diesel spray, part of the natural gas stops at the head of jet, which affects the gas volume fraction of the whole jet. The smaller the injection pressure of natural gas is, the greater the effect of diesel is. The velocity is decreased from the head to the bottom of the natural gas jet. There are many vortices and vorticity fields in the middle of the jet, and there is a small turbulence intensity in the area where the diesel spray and the natural gas jet collide.
ERFAN I, CHITSAZ I, ZIABASHARHAGH M, et al. Injection characteristics of gaseous jet injected by a single-hole nozzle direct injector\[J\]. Fuel, 2015, 160:24-34.
［2］
HUANG H Z, ZHU Z J, CHEN Y J, et al. Experimental and numerical study of multiple injection effects on combustion and emission characteristics of natural gas-diesel dual-fuel engine\[J\].Energy Conversion and Management,2019,183:84-86.
WANG W L, ZHANG X D, KUANG X, et al. Investigation on combustion and emissions characteristics of diesel engine fueled with bio-diesel\[J\]. Journal of Yangzhou University(Natural Science Edition), 2017,20(2)：55-59.（in Chinese）
ZHAO Y S, ZHENG R L. Design of electronic fuel injection system for the dual-fuel engine\[J\]. Drainage and Irrigation Machine，2003(6):33-36.（in Chinese）
［5］
袁小飞. 缸内直喷天然气发动机燃气喷射数值模拟研究\[D\]. 北京：北京交通大学, 2014.
［6］
BRUNEAUX G.A study of mixture formation in direct injection diesel like conditions using quantitative fuel concentration visualizations in a gaseous fuel jet\[J\]. SAE Technical Papers,doi：10.4271/2002-01-1632.
［7］
YU J Z, VUORINEN V, HILLAMO H, et al. An experimental investigation on the flow structure and mixture formation of low pressure ratio wall-impinging jets by a natural gas injector\[J\]. Journal of Natural Gas Science and Engineering, 2012，9: 1-10.
［8］
KUTI O A, NISHIDA K, ZHU J Y, et al. Experimental studies on spray and gas entrainment characteristics of bio-diesel fuel: Implications of gas entrained and fuel oxygen content on soot formation\[J\]. Energy, 2013, 57:434-442.
WANG C Y, LIU F S, WU W F,et al. Experimental study of the impinging jet diffusion and entrainment for high-pressure injected methane\[J\].Transactions of CSICE, 2012,30(5): 423-428.(in Chinese)
DENG P, HUANG R H, MA Y J, et al. Atomization and mixture formation characteristics of ethanol-diesel and diesel under intensified mixing conditions\[J\]. Transactions of CSICE,2014，32(2):144-151.(in Chinese)
［11］
SETTLES G S. Schlieren and Shadowgraph Techniques\[M\]. Berlin, Germany：Springer, 2001.
LI M H, ZHANG Q, LI G X, et al. Effects of diesel injection quantity and injection interval on emission characteristics of directly injected natural gas engine \[J\]. Transactions of the CSAE, 2016, 32(6): 95-100. (in Chinese)
2021, Vol. 42 
