Air Entrainment and Combustion Process of High-Pressure Gas Jet in Gas Direct Injection Engines

2017 ◽  
Vol 2017.9 (0) ◽  
pp. C304
Author(s):  
Tharshan Thiripuvanam ◽  
Hiroshi Tashima ◽  
Daisuke Tsuru
Keyword(s):  
High Pressure ◽  
Direct Injection ◽  
Combustion Process ◽  
Air Entrainment ◽  
Gas Jet ◽  
Direct Injection Engines

A Numerical Investigation on Mixing Characteristics of Natural Gas Jets With High-Pressure Injection

2021 ◽  
Author(s):  
Long Liu ◽  
Tianyang Dai ◽  
Qian Xiong ◽  
Yuehua Qian ◽  
Bo Liu
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Air Entrainment ◽  
Gas Jet ◽  
Swirl Ratio ◽  
Marine Engine ◽  
Low Speed ◽  
Pressure Injection ◽  
Mixing Characteristics ◽  
High Pressure Injection

Abstract With increasingly stringent emissions limitation of greenhouse gas and atmospheric pollutants for ship, the direct injection of natural gas on the cylinder head with high-pressure injection is an effective method to make a high power output and decrease harmful gas emissions in marine natural gas dual fuel engines. However, the effects on mixing characteristics of high-pressure natural gas underexpanded jet have not been fully understood. Especially, the injection pressure is up to 30 MPa with large injection quantity and critical surrounding gas conditions for the low-speed two-stroke marine engine. Therefore, this research is focused on the flow and mixing process of the natural gas jet with high-pressure injection under the in-cylinder conditions of low-speed two-stroke marine engine. The gas jet penetration, the distribution of velocity and density, the equivalence ratio and air entrainment have been analyzed under different nozzle hole diameters by numerical simulation. The effects of surrounding gas conditions including pressure, temperature and swirl ratio on air entrainment and equivalence ratio distribution were studied in detail. From the numerical simulation, it is found that the mixing characteristics of natural gas jet can be improved under in-cylinder conditions of higher ambient temperature and swirl ratio, which is relevant to the low-speed two-stroke marine engine.

Detecting and Correcting Cylinder Imbalance in Direct Injection Engines

2000 ◽  
Vol 123 (3) ◽  
pp. 413-424 ◽  
Author(s):  
M. J. van Nieuwstadt ◽  
I. V. Kolmanovsky
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Direct Injection Engines ◽  
High Speed Diesel ◽  
On Line ◽  
Manufacturing Accuracy ◽  
Adaptation Scheme

Modern direct injection engines feature high pressure fuel injection systems that are required to control the fuel quantity very accurately. Due to limited manufacturing accuracy these systems can benefit from an on-line adaptation scheme that compensates for injector variability. Since cylinder imbalance affects many measurable signals, different sensors and algorithms can be used to equalize torque production by the cylinders. This paper compares several adaptation schemes that use different sensors. The algorithms are evaluated on a cylinder-by-cylinder simulation model of a direct injection high speed diesel engine. A proof of stability and experimental results are reported as well.

scholarly journals CFD Analysis of the Fuel–Air Mixture Formation Process in Passive Prechambers for Use in a High-Pressure Direct Injection (HPDI) Two-Stroke Engine

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2846 ◽  
Author(s):  
Marco Ciampolini ◽  
Simone Bigalli ◽  
Francesco Balduzzi ◽  
Alessandro Bianchini ◽  
Luca Romani ◽  
...  
Keyword(s):  
High Pressure ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Low Temperature Combustion ◽  
Mixture Formation ◽  
Revolution Speed ◽  
Aspect Ratios ◽  
Scavenging Efficiency ◽  
Stroke Engine

The research on two-stroke engines has been focused lately on the development of direct injection systems for reducing the emissions of hydrocarbons by minimizing the fuel short-circuiting. Low temperature combustion (LTC) may be the next step to further improve emissions and fuel consumption; however, LTC requires unconventional ignition systems. Jet ignition, i.e., the use of prechambers to accelerate the combustion process, turned out to be an effective way to perform LTC. The present work aims at proving the feasibility of adopting passive prechambers in a high-pressure, direct injection, two-stroke engine through non-reactive computational fluid dynamics analyses. The goal of the analysis is the evaluation of the prechamber performance in terms of both scavenging efficiency of burnt gases and fuel/air mixture formation inside the prechamber volume itself, in order to guarantee the mixture ignitability. Two prechamber geometries, featuring different aspect ratios and orifice numbers, were investigated. The analyses were replicated for two different locations of the injection and for three operating conditions of the engine in terms of revolution speed and load. Upon examination of the results, the effectiveness of both prechambers was found to be strongly dependent on the injection setup.

The process of tip wetting at the spray injection end

2019 ◽  
Vol 22 (1) ◽  
pp. 125-139
Author(s):  
Jérôme Hélie ◽  
Nicolas Lamarque ◽  
Jean-Luc Fremaux ◽  
Philippe Serrecchia ◽  
Maziar Khosravi ◽  
...  
Keyword(s):  
High Pressure ◽  
Particle Number ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Pollutant Emissions ◽  
Direct Access ◽  
Direct Injection Engines ◽  
Carbon Particles ◽  
Optical Visualization ◽  
Number Of Particles

Gasoline direct injection engines mainly use multi-hole high-pressure injectors. To respect the current pollutant regulation (particle number and particle mass) and continue to decrease pollutant emissions in the future, it is of outmost importance to identify the various sources of carbon particles. In gasoline direct injection, tip wetting can generate a progressive tip sooting that can be a source of large number of particles especially in hot engine conditions. The different topics related to the tip wetting are investigated here without counterbore after the metering hole in order to have a direct access to the optical visualization. In this article, the different phases of the tip wetting are identified experimentally and phenomenological models are proposed.

A Comprehensive Fuel Spray Model for High Pressure Fuel Injectors

2008 ◽  
Author(s):  
Gerald J. Micklow ◽  
Krishna Ankem ◽  
Tarek Abdel-Salam
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Gas Turbine ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Pressure ◽  
Pollutant Emission ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Fuel Injectors

Understanding the physics and chemistry involved in spray combustion, with its transient effects and the inhomogeneity of the spray is quite challenging. For efficient operation of both internal combustion and gas turbine engines, great insight into the physics of the problem can be obtained when a computational analysis is used in conjunction with either an experimental program or through published experimental data. The main area to be investigated to obtain good combustion begins with the fuel injection process and an accurate description of the mean diameter of the fuel particle, injection pressure, drag coefficient, rate shaping etc must be defined correctly. This work presents a methodology to perform the task set out in the previous paragraph and uses experimental data obtained from available literature to construct a semi-empirical numerical model for high pressure fuel injectors. A modified version of a multidimensional computer code called KIVA3V was used for the computations, with improved sub-models for mean droplet diameter, injection pressure, injection velocity, and drop distortion and drag. The results achieved show good agreement with the published in-cylinder experimental data for a Volkswagen 1.9 L turbo-charged direct injection internal combustion engine under actual operating conditions. It is crucial to model the spray distribution accurately, as the combustion process and the resulting temperature distribution and pollutant emission formation is intimately tied to the in-cylinder fuel distribution. The present scheme has achieved excellent agreement with published experimental data and will make an important contribution to the numerical simulation of the combustion process and pollutant emission formation in compression ignition direct injection engines and gas turbine engines.

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