An Experimental Investigation of Combustion Chamber Design Parameters for Hot Surface Ignition

2014 ◽  
Author(s):  
Dan Chown ◽  
Charles Habbaky ◽  
James S. Wallace
Keyword(s):  
Combustion Chamber ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Design Parameters ◽  
Opening Angle ◽  
Fuel Injector ◽  
Fuel Utilization ◽  
Dominant Effect ◽  
Glow Plug ◽  
Injector Nozzle

Natural gas requires some form of ignition assist in order to autoignite in the time available in a compression ignition engine. Ignition assist using a glow plug — a heated surface — was investigated using an apparatus that consists of an optically accessible constant volume combustion bomb coupled to a single cylinder CFR engine through the spark plug port. Previous studies have shown the dominant effect of fuel injection pattern and glow plug shield geometry on ignition delay, combustion rate, and fuel utilization with 1–3 fuel jets. New work has been carried out to evaluate the ability of a shielded glow plug to ignite a full nine jet symmetrical fuel injection pattern. The sensitivity of ignition delay and fuel utilization to fuel injector angular alignment relative to the glow plug, glow plug shield opening angle, and glow plug power was analyzed using in-cylinder pressure data and exhaust hydrocarbon emissions concentrations. Two glow plugs, one conventional metallic and one ceramic, and two fuel injector nozzle orifice sizes were evaluated for their effect on ignition delay. The ignition and flame propagation process was observed using high speed images. Glow plug power was shown to have a dominant effect on ignition delay and fuel utilization, with a secondary effect from fuel injector angle and glow plug opening angle. The ceramic glow plug was shown to provide superior ignition assist while consuming less power than the metallic glow plug. The larger fuel injector nozzle size increased ignition delay times, likely due to increased convective cooling of the glow plug surface from the larger gas jet. Acquired images show that the smaller fuel injector orifice size created a flammable path in two distinct areas; along the periphery of the fuel jets and between the fuel jets. The higher mass flow rate and subsequent increased mixing of the larger fuel jets created flammable paths throughout the entirety of the combustion chamber.

scholarly journals Modeling a fuel injector for a two-stroke diesel engine

2017 ◽  
Vol 170 (3) ◽  
pp. 147-153
Author(s):  
Rafał SOCHACZEWSKI ◽  
Zbigniew CZYŻ ◽  
Ksenia SIADKOWSKA
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Fuel Injection ◽  
Maximum Load ◽  
Fuel Injector ◽  
Dimensional Model ◽  
Flow Area ◽  
Fuel Mass ◽  
One Dimensional ◽  
Injector Nozzle

This paper discusses the modeling of a fuel injector to be applied in a two-stroke diesel engine. A one-dimensional model of a diesel injector was modeled in the AVL Hydsim. The research assumption is that the combustion chamber will be supplied with one or two spray injectors with a defined number of nozzle holes. The diameter of the nozzle holes was calculated for the defined options to provide a correct fuel amount for idling and the maximum load. There was examined the fuel mass per injection and efficient flow area. The studies enabled us to optimize the injector nozzle, given the option of fuel injection into the combustion chamber to be followed.

Numerical Studies of Glow Plug Shield on Natural Gas Ignition Characteristics in a CI Engine

2016 ◽  
Author(s):  
Kang Pan ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Numerical Study ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Injection Angle ◽  
Glow Plug ◽  
Gas Ignition ◽  
Ignition And Combustion

This paper presents a numerical study on fuel injection, ignition and combustion in a direct-injection natural gas (DING) engine with ignition assisted by a shielded glow plug (GP). The shield geometry is investigated by employing different sizes of elliptical shield opening and changing the position of the shield opening. The results simulated by KIVA-3V indicated that fuel ignition and combustion is very sensitive to the relative angle between the fuel injection and the shield opening, and the use of an elliptical opening for the glow plug shield can reduce ignition delay by 0.1∼0.2ms for several specific combinations of the injection angle and shield opening size, compared to a circular shield opening. In addition, the numerical results also revealed that the natural gas ignition and flame propagation will be delayed by lowering a circular shield opening from the fuel jet center plane, due to the blocking effect of the shield to the fuel mixture, and hence it will reduce the DING performance by causing a longer ignition delay.

Autoignition of Heavy Fuel Oil Sprays at High Pressures and Temperatures

1990 ◽  
Vol 112 (3) ◽  
pp. 324-330 ◽  
Author(s):  
R. S. G. Baert
Keyword(s):  
Combustion Chamber ◽  
Ignition Delay ◽  
High Pressures ◽  
Fuel Injection ◽  
Fuel Oil ◽  
Single Shot ◽  
Heavy Fuel Oil ◽  
Fuel Oils ◽  
Constant Volume Combustion Chamber ◽  
Heavy Fuel Oils

This paper reports on an experimental study of the autoignition behavior of several heavy fuel oils in a large constant-volume combustion chamber with single-shot injection. In the experiments the pressure and the temperature of the air in the combustion chamber before fuel injection varied between 30 and 70 bar and between 730 and 920 K. Illumination delay and pressure delay values have been correlated with these pressures and temperatures. It is shown that for all but one of the fuels examined, ignition delay ranking changes little with the choice of ignition delay definition, but more with the pressure and temperature conditions in the combustion chamber. The usefulness of the Calculated Carbon Aromaticity Index is discussed.

Computational Studies of Glow Plug Ignition of Injected High Pressure Gas Jets

2015 ◽  
Author(s):  
Kang Pan ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Ignition Delay ◽  
Numerical Study ◽  
Pressure Rise ◽  
Air Gap ◽  
Time Difference ◽  
Glow Plug ◽  
Gas Ignition ◽  
Ignition And Combustion

A numerical study of ignition and combustion in a glow plug (GP) assisted direct-injection natural gas (DING) engine is presented in this paper. The glow plug is shielded and the shield design is an important part of the combustion system development. The results simulated by KIVA-3V indicated that the ignition delay (ID) predicted by an in-cylinder pressure rise was different from that based on a temperature rise, attributed to the additional time required to burn more fuel to obtain a detectable pressure rise in the combustion chamber. This time difference for the ignition delay estimation can be 0.5 ms, which is significant relative to an ignition delay value of less than 2 ms. To further evaluate the time difference between the two different methods of ignition delay determination, sensitivity studies were conducted by changing the glow plug temperature, and rotating the glow plug shield opening angle towards the fuel jets. The results indicated that the ID method time difference varied from 0.3 to 0.8 ms for different combustion chamber configurations. In addition, this study also investigated the influences of different glow plug shield parameters on the natural gas ignition and combustion characteristics, by modifying the air gap between the glow plug and its shield, and by changing the shield opening size. The computational results indicated that a bigger air gap inside the shield can delay gas ignition, and a smaller shield opening can block the flame propagation for some specific fuel injection angles.

scholarly journals Modern Technologies for Micro-drilling of the Fuel Injector Nozzle used in Motor Vehicles - A Review of the Literature

2021 ◽  
Vol 343 ◽  
pp. 03007
Author(s):  
Dorinel Popa ◽  
Cristin-Olimpiu Morariu
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Production Capacity ◽  
Motor Vehicles ◽  
Drilling Process ◽  
Fuel Injector ◽  
Pilot Hole ◽  
Injector Nozzle ◽  
Electro Discharge Machining ◽  
Micro Drilling

To cope with the pollution norms and an improvement of the combustion of the internal combustion engines, high-quality holes with diameters smaller than 145 µm are needed for the manufacture of fuel injection nozzles. The current practice of using drilling by electro-discharge machining of fuel injection nozzles is limited in terms of the size of the hole it can efficiently produce and the time required for drilling. In addition, the cost of the tool is high. This paper presents an investigation into a sequential laser and electro-discharge micro-drilling technique for the manufacture of fuel injection nozzles. A pilot hole drilled with a laser is removed by electrodischarge. It was found that this hybrid process eliminated the problems of reformed and heat-affected areas usually associated with the laser drilling process. The new process has allowed a reduction in total drilling time compared to standard electro-discharge machining drilling, as less material is removed from the electro-discharge machining. The quality of the holes is as good as direct electro-discharge machining drilling. This technique has allowed valuable cost savings and increased production capacity for the manufacture of the fuel injector nozzle.

The Effect of Nozzle Breakaway Pressure on the Spray Pattern Formed

2012 ◽  
Vol 248 ◽  
pp. 173-178
Author(s):  
Adedamola Najeem Peleowo
Keyword(s):  
Fuel Injection ◽  
Travel Speed ◽  
Main Function ◽  
Operating Pressure ◽  
Fuel Injector ◽  
Test Rig ◽  
Spray Pattern ◽  
Injector Nozzle ◽  
Schlieren Photography ◽  
Optical Mirrors

The main function of a fuel injector nozzle is to break fuels into droplets, form the spray pattern, and propel the droplets into a combustion chamber. The amount of spray volume at a given operating pressure, the travel speed, and spacing between the jets of fuel can also be determined by the nozzle. In fuel injection, the smallest possible droplet size is desired for the most flow. This work presents an opportunity to use the Schlieren arrangement as a visualization method to view the flow of fuel from a three-hole fuel injector nozzle which cannot be seen by the naked eye. The jet flow of diesel Fuel was investigated by Schlieren photography. A test rig was designed and constructed to accommodate the nozzle; optical mirrors were arranged according to Schlieren specifications in order to allow the jet to be photographed. The breakaway pressure of the nozzle was varied between 60bar to 80bar. Each hole of the nozzle is 0.26mm in diameter and 120° apart; the third jet could not be seen from the images because the camera took x-y dimension images. The spray pattern observed from the two dimensional images of the jets developed were seen to be well dispersed. Su et al [3] found that emissions could be reduced in diesel engines if the injector nozzle produces smaller and more dispersed droplets.

Damping of Combustion Instabilities Through Pseudo-Active Control

2018 ◽  
Author(s):  
Jesús Oliva ◽  
Ennio Luciano ◽  
Javier Ballester
Keyword(s):  
Combustion Chamber ◽  
Active Control ◽  
Gas Turbines ◽  
Fuel Injection ◽  
Pressure Oscillation ◽  
Practical Reasons ◽  
Fuel Injector ◽  
Secondary Fuel ◽  
Pilot Fuel ◽  
Instability Control

Active instability control techniques have demonstrated very good capabilities to correct combustion oscillations but, due to high costs and other practical reasons, have not achieved the success expected in gas turbines engines. A different approach, named here as ‘pseudo-active instability control’, has been explored and the first results are presented in this work. In this case, the flow of non-premixed pilot fuel is modulated by passive methods: the pressure oscillation in the combustion chamber induces a velocity fluctuation at the secondary fuel injector. In principle, damping of the instability may be achieved if the heat release oscillations due to the secondary fuel are out of phase with those of the main flame. This work reports a first exploration of this strategy, aimed mainly at performing a proof of the concept. An experimental study has been carried out in a laboratory premixed combustor with pilot fuel injection. The relationship between the fluctuations of pressure in the combustion chamber and those of velocity at the injector was studied both experimentally (hot wire anemometry) and theoretically (1-D acoustic model of the injection line). Combustion tests in limit cycle conditions demonstrated that modifications in the geometry of the secondary injection affected the pressure fluctuations inside the combustion chamber. Depending on the geometry (and, hence, acoustic impedance), the instability was enhanced or damped. This demonstrates that the proposed ‘pseudo-active control’ can produce similar effects (at least, qualitatively) to those of active control, but only using passive means, as initially postulated.

scholarly journals Numerical Analysis of Fuel Injector Nozzle Geometry - Influence on Liquid Fuel Contraction Coefficient and Reynolds Number

2019 ◽  
Vol 57 (1) ◽  
pp. 23-45
Author(s):  
Lino Kocijel ◽  
Vedran Mrzljak ◽  
Maida Čohodar Husić ◽  
Ahmet Čekić
Keyword(s):  
Reynolds Number ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Injection Rate ◽  
Nozzle Diameter ◽  
Nozzle Geometry ◽  
Fuel Injector ◽  
Contraction Coefficient ◽  
Nozzle Length ◽  
Injector Nozzle

This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel contraction coefficient and Reynolds number. The main three fuel injector nozzle geometry parameters: nozzle diameter (d), nozzle length (l) and nozzle inlet radius (r) have a strong influence on the liquid fuel contraction coefficient and Reynolds number. The variation of the nozzle geometry variables at different liquid fuel pressures, temperatures and injection rates was analyzed. The liquid fuel contraction coefficient and Reynolds number increase with an increase in the nozzle diameter, regardless of the fuel injection rate. An increase in the r/d ratio causes an increase in the fuel contraction coefficient, but the increase is not significant after r/d = 0.1. A nozzle length increase causes a decrease in the fuel contraction coefficient. Increase in the nozzle length of 0.5 mm causes an approximately similar decrease in the contraction coefficient at any fuel pressure and any nozzle length. Fuel injectors should operate with minimal possible nozzle lengths in order to obtain higher fuel contraction coefficients.

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