Effect of injection timing on the ignition process of n-heptane spray flame in a methane/air environment

Fuel ◽  
2019 ◽  
Vol 245 ◽  
pp. 345-359 ◽  
Author(s):  
Haiqiao Wei ◽  
Wanhui Zhao ◽  
Jiayue Qi ◽  
Zongkuan Liu ◽  
Lei Zhou
Keyword(s):  
Injection Timing ◽  
Ignition Process ◽  
Spray Flame

Different Diesel Engine Ignition Regimes With a Single Injection

2015 ◽  
Author(s):  
Mianzhi Wang ◽  
Zhengxin Xu ◽  
Saifei Zhang ◽  
Chia-fon F. Lee
Keyword(s):  
Diesel Engine ◽  
Single Injection ◽  
Direct Injection ◽  
Phase Curve ◽  
Injection Timing ◽  
Ignition Process ◽  
Injection Scheme ◽  
Air Mixing ◽  
Test Engine ◽  
Combustion Regimes

A simple single injection scheme is used to understand the fundamental processes of diesel engine ignition. Two different combustion regimes, partially premixed combustion (PPC), and conventional direct injection compression ignition (DICI), are computationally achieved with the single injection scheme in a 3-D CFD program. An ignition phase curve covering the two combustion regimes is proposed and verified by numerical simulation. The ignition phase curve is used to reveal the underlying physics of each regime. It is found that the interaction among piston motion, chemical kinetics, fuel-air mixing, and injection event differs the two combustion regimes. The conventional DICI mode ignition is dominated by injection timing and affected by the mixture pressure and temperature during the flame induction period. In the PPC mode, the over-mixing effect of the fuel affects largely the ignition process. The variations of the moment of cool flame onset and high temperature ignition are discussed in detail. The differences between the proposed and calculated ignition phase curve are due to the specific piston and injector design of the test engine for which calculations are done. Finally, the effects of intake temperature on the ignition phase curve are explained based on numerical results.

Experimental investigation of the ignition process in a separated dual-swirl spray flame

2020 ◽  
Vol 219 ◽  
pp. 161-177 ◽  
Author(s):  
Siheng Yang ◽  
Chi Zhang ◽  
Yuzhen Lin ◽  
Xin Xue ◽  
Xiaohua Gan
Keyword(s):  
Experimental Investigation ◽  
Ignition Process ◽  
Spray Flame

Analysis of Fuel Injection Parameter on Biodiesel and Diesel Spray Characteristics Using Common Rail System

2014 ◽  
Vol 974 ◽  
pp. 362-366 ◽  
Author(s):  
Amir Khalid ◽  
Azwan Sapit ◽  
M.N. Anuar ◽  
Him Ramsy ◽  
Bukhari Manshoor ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Common Rail ◽  
Spray Angle ◽  
Injection System ◽  
Injection Timing ◽  
Ignition Process ◽  
Mixture Formation ◽  
Spray Characteristics ◽  
Penetration Length

Precise control of fuel injection is essential in modern diesel engines especially in controlling the precise injection quantity, flexible injection timing, flexible rate of injection with multiple injections and high injection pressures. It was known that the fuel-air mixing is mainly influenced by the fuel injection system and injector nozzle characteristics. Thus, mixture formation during ignition process associated with the exhaust emissions. The purpose of this study is to investigate the influence of spray characteristics on the mixture formation. In this study, common rail injector systems with different model of injector were used to simulate the actual mixture formation inside the engine chamber. The optical visualization system was constructed with a digital video camera in order to investigate the detailed behavior of mixture formation. This method can capture spray penetration length, spray angle, spray evaporation and mixture formation process clearly. The spray characteristic such as the penetration length, spray angle and spray area are increasing when the injection pressure increased. The mixture formation can be improved effectively by increasing the injection pressure.

scholarly journals Polydisperse spray flame ignition by a pulsed heat flux

2021 ◽  
pp. 175682772110141
Author(s):  
G Kats ◽  
JB Greenberg
Keyword(s):  
Critical Energy ◽  
Operating Conditions ◽  
Ignition Process ◽  
Fuel Droplets ◽  
Spray Flame ◽  
Theoretical Predictions ◽  
History Of ◽  
Flame Ignition ◽  
Entire History ◽  
Global Reaction

A mathematical analysis of the ignition of a polydisperse spray/air mixture by an infinite surface heated in a pulsed manner is presented. In contrast to previous work in the literature, the entire history of the ignition process is accounted for starting from the flame-embryo progenitor stage, through the thermal runaway stage to the final flame propagation stage. For tractability at the current stage, the chemical kinetics is taken to be that of a single global reaction. The spray is modeled using the sectional approach and the influence of fuel spray characteristics on ignition is determined. Good agreement was found between the theoretical predictions and full numerical simulations. Delay in ignition due to the build-up of vapor from the fuel droplets as well as heat loss to the droplets for evaporation are found to play a significant role under certain operating conditions. Comparison between the critical energy flux and the initial spray polydispersity revealed small differences for larger values of the pulse duration but more significant minor differences for smaller pulse durations. Despite these seemingly minor differences, it was shown that the initial spray polydispersity can have a critical influence on whether flame ignition will occur or fail, even for sprays having the same initial SMD.

A Numerical Simulation of Analysis of Backfiring Phenomena in a Hydrogen Fuelled Spark Ignition Engine

2015 ◽  
Author(s):  
K. A. Subramanian ◽  
B. L. Salvi
Keyword(s):  
Hot Spot ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Injection Timing ◽  
Ignition Process ◽  
Si Engine ◽  
Engine Operation ◽  
Study Results ◽  
Residual Gas

Hydrogen utilization in spark ignition engines could reduce urban pollution including particulate matter as well as greenhouse gas (carbon dioxide) emission. However, backfiring, which is an undesirable combustion process of intake charge in hydrogen fuelled spark ignition (SI) engine with manifold based injection, is one of the major technical issues in view of safety as well as continuous engine operation as ignition process could proceed instantaneously due to less ignition energy requirement of hydrogen. Backfiring occurs generally during suction stroke as the hydrogen-air charge interacts with residual gas resulting in flame growth and propagation towards upstream of engine’s intake manifold resulting in stalling of engine operation and high risk of safety. This work is aimed at analysis of backfiring in a hydrogen fuelled SI engine. The results indicate that backfiring is mainly function of residual gas temperature, start of hydrogen injection timing and equivalence ratio. Any hot-spot present in the cylinder would act as ignition source resulting in more chances of backfiring. In addition to this, CFD analysis was carried out in order to assess flow characteristics of hydrogen and air during suction stroke in intake manifold. Furthermore, numerical analysis of intake charge velocity, flame speed (deflagration), and flame propagation (backfiring) towards upstream of intake manifold was also carried out. Some notable points of backfiring control strategy including exhaust gas recirculation (EGR) and retarded (late) hydrogen injection timing are emerged from this study for minimizing chance of backfiring. This study results are useful for development of dedicated spark ignition engine for hydrogen fuel in the aspects of elimination of backfiring.

scholarly journals Large-eddy simulation of the injection timing effects on the dual-fuel spray flame

Fuel ◽  
2021 ◽  
pp. 122445
Author(s):  
Shijie Xu ◽  
Shenghui Zhong ◽  
Ahmad Hadadpour ◽  
Yan Zhang ◽  
Kar Mun Pang ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Fuel Spray ◽  
Dual Fuel ◽  
Injection Timing ◽  
Eddy Simulation ◽  
Spray Flame ◽  
Large Eddy ◽  
Timing Effects

Investigation of Reaction Products Obtained from Ignition Process of n-Heptane / Air Mixtures on Free Hot Surface

2017 ◽  
Vol 68 (5) ◽  
pp. 1035-1039
Author(s):  
Maria Mitu ◽  
Elisabeth Brandes
Keyword(s):  
Stainless Steel ◽  
Ignition Temperature ◽  
Ambient Pressure ◽  
Ignition Process ◽  
Reaction Products ◽  
Hot Surface

The ignition behaviour at ambient pressure (p0 between 98.0 kPa and 101.3 kPa) of different concentrations of homogenous n-heptane/air mixtures on stainless steel hot surface as well as the composition of the reaction products have been investigated. Although all reaction products are present in each burned n-heptane/air mixture, a correlation between the lowest ignition temperature and the quantitve composition of the reaction products is not obvious.

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