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Journal Article

Fuel Spray Evaporation and Mixture Formation Processes of Ethanol/Gasoline Blend Injected by Hole-Type Nozzle for DISI Engine

2012-10-23
2012-32-0018
Ethanol is regarded as the promising alternative fuel for gasoline to meet the strict low emission standard for spark ignition engines. In this study, the spray mixture formation process for different ethanol blended fuels, including E0 (gasoline), E85 (85% volume of ethanol and 15% volume of gasoline) and E100 (ethanol), has been evaluated using hole-type nozzle by the measurement of Laser Absorption Scattering (LAS) technique in a constant volume vessel. Based on the principle of LAS, the quantitative vapor and liquid phase distribution from different ethanol blended fuel can be obtained by the light extinction regime. Aiming to analyze the effect of mixture formation and evaporation for different components of blended fuel or pure gasoline and ethanol, the vapor distribution of gasoline was determined by using p-xylene, which had similar physical properties to gasoline, especially higher boiling temperature components, and higher absorption for ultraviolet.
Technical Paper

Fuel Spray Combustion of Waste Cooking Oil and Palm Oil Biodiesel: Direct Photography and Detailed Chemical Kinetics

2013-10-14
2013-01-2554
This paper studies the ignition processes of two biodiesel from two different feedstock sources, namely waste cooked oil (WCO) and palm oil (PO). They were investigated using the direct photography through high-speed video observations and detailed chemical kinetics. The detailed chemical kinetics modeling was carried out to complement data acquired using the high-speed video observations. For the high-speed video observations, an image intensifier combined with OH* filter connected to a high-speed video camera was used to obtain OH* chemiluminscence image near 313 nm. The OH* images were used to obtain the experimental ignition delay of the biodiesel fuels. For the high-speed video observations, experiments were done at an injection pressure of 100, 200 and 300 MPa using a 0.16 mm injector nozzle.
Technical Paper

Cross-Flow Effect on Behavior of Fuel Spray Injected by Hole-Type Nozzle for D.I. Gasoline Engine

2013-10-14
2013-01-2553
Spray characteristics are of great importance to achieve fuel economy and low emissions for a D.I. gasoline engine. In this study, the characteristics of the fuel spray as well as its interaction with a cross-flow were investigated. The fuel was injected by a VCO injector into an optically accessible rectangular wind tunnel under the normal temperature and pressure, in which the direction of the injection was perpendicular to the direction of the cross-flow. The velocity of the cross-flow varied from 0 to 10 m/s while the injection pressure was 5 and 10 MPa. With using the high speed video camera and the PIV system, the spray profile, velocity distribution and the penetration distance were measured. The lower penetration distance can be obtained with the lower injection pressure and the increased velocity of the cross-flow, however the injected fuel expands along the direction of the cross-flow, which indicates that spray atomization and mixing of fuel and air are enhanced.
Technical Paper

Effects of Injection Pressure and Ambient Gas Density on Fuel - Ambient Gas Mixing and Combustion Characteristics of D.I. Diesel Spray

2011-08-30
2011-01-1819
The fuel-ambient gas interaction process of the free diesel spray injected from the micro-hole nozzle (0.08 mm) into the quiescent and engine-like ambient gas condition was investigated by means of the laser-induced fluorescence - particle image velocimetry (LIF-PIV) technique in non-evaporating condition. Direct photography with high speed video camera and two color pyrometry were applied to analyze the evaporation spray and flame characteristics. Three injection pressures from 100, 200 to 300 MPa and two ambient gas densities of 11 and 15 kg/m₃ were selected as testing conditions. The entrained mass flow rate of the ambient gas through the whole spray boundary, the ratio of the total ambient gas entrainment rate to the fuel injection rate, etc., were calculated by using the ambient gas velocity data obtained by the LIF-PIV technique and used to correlate the combustion behavior.
Journal Article

Effect of Injection Pressure on Ignition, Flame Development and Soot Formation Processes of Biodiesel Fuel Spray

2010-09-28
2010-32-0053
The effect of injection pressure ranging from 100 to 300MPa on the ignition, flame development and soot formation characteristics of biodiesel fuel spray using a common rail injection system for direct injection (D.I.) diesel engine was investigated. Experiments were carried out in a constant volume vessel under conditions similar to the real engine condition using a single hole nozzle. Biodiesel fuels from two sources namely; palm oil (BDFp) and cooked oil (BDFc) with the commercial JIS#2diesel fuel were utilized in this research. The OH chemiluminescence technique was used to determine the ignition and the lift-off length of the combusting flame. The natural luminosity technique was applied to study the flame development and the two color pyrometry was applied for the soot formation processes. Ignition delay decreased as the injection pressure progressed from 100 to 300MPa. This was as a result of the enhanced mixing achieved at higher injection pressures.
Journal Article

Small Injection Amount Fuel Spray Characteristics Injected by Hole-Type Nozzle for D.I. Diesel Engine

2014-11-11
2014-32-0124
Spray characteristics under very small injection amount injected by the hole-type nozzle for a D.I. Diesel engine were investigated using the spray test rig consisting a high-pressure and high-temperature constant volume vessel with optical accesses and a common rail injection system. The Laser Absorption Scattering (LAS) technique was used to visualize the liquid and vapor phase distributions in the evaporating spray. In the very small injection amount condition of the evaporating and free (no wall impingement) spray, the both spray tip penetration and spray angle are larger than those of the non-evaporating free spray. This tendency contradicts the previous observation of the diesel spray with large injection amount and the quasi steady state momentum theory. In the case of the spray impinging on a 2-dimensional piston cavity wall, the spray tip penetration of the evaporating spray is larger than that of the non-evaporating spray.
Technical Paper

Group-Hole Nozzle Effects on Mixture Formation and In-cylinder Combustion Processes in Direct-Injection Diesel Engines

2007-10-29
2007-01-4050
The group-hole (GH) nozzle concept that uses two closely spaced micro-orifices to substitute the conventional single orifice has the potential to facilitate better fuel atomization and evaporation, consequently attenuate the soot emission formed in direct-injection (D.I.) diesel engines. Studies of quantitative mixture properties of the transient fuel spray injected by the group-hole nozzles were conducted in a constant volume chamber via the laser absorption-scattering (LAS) technique, in comparison with conventional single-hole nozzles. Specific areas investigated involved: the non-evaporating and the evaporating ambient conditions, the free spray and the spray impinging on a flat wall conditions. The particular emphasis was on the effect of one of key parameters, the interval between orifices, of the group-hole (SH) nozzle structure.
Technical Paper

Mixture Formation and Combustion Processes of Multi-Hole Nozzle with Micro Orifices for D.I. Diesel Engines

2007-10-29
2007-01-4049
In order to investigate effects of the multi-hole nozzle with micro orifices on mixture formation processes in Direct-Injection Diesel engines, mixture characteristics were examined via an ultraviolet-visible laser absorption scattering (LAS) technique under various injectors. The injection quantity per orifice per cycle was reduced by nozzle hole sizes. The LAS technique can provide the quantitative and simultaneous measurements of liquid and vapor phases concentration distributions inside of the fuel spray. Mass of ambient gas entrained into the spray, liquid/ vapor mass and mean equivalence ratio of total fuel were obtained based on Lambert Beer's law. As a result, the leaner and more homogeneous fuel-gas mixture can be achieved by reducing the nozzle hole diameter, in the meanwhile more ambient gas were entrained into the spray. Moreover, relationships between mixture formation and D.I.
Technical Paper

A challenge to vapor distribution measurement of multi-component evaporating fuel spray via laser absorption-scattering (LAS) technique

2007-07-23
2007-01-1892
In the present study, a challenge has been made to quantitatively determine the vapor phase concentration distributions in an evaporating multicomponent fuel spray using the LAS imaging technique. The theoretical considerations were particularly given when applying the LAS imaging technique to the multicomponent fuel spray and reconstructing the vapor concentration distributions from the spray images.
Technical Paper

Effects of Group-hole Nozzle Specifications on Fuel Atomization and Evaporation of Direct Injection Diesel Sprays

2007-07-23
2007-01-1889
The group-hole nozzle concept is regarded as a promising approach to facilitate better fuel atomization and evaporation for direct injection diesel engine applications. In the present work, the spray and mixture properties of group-hole nozzle with close, parallel or a small included angle orifices were investigated experimentally by means of the ultraviolet-visible laser absorption-scattering (LAS) imaging technique, in comparison with the conventional single-hole nozzle. Three series of group-hole nozzles were designed to investigate the effect of group-hole nozzle specification while varying the included angle and interval between the orifices. The results suggested that: 1) Group-hole nozzle with very close, parallel orifices presents the similar spray characteristics with those of the single-hole nozzle.
Technical Paper

Spray and Mixture Properties of Hole-Type Injector for D. I. Gasoline Engine-Comparison of Experiment and CFD Simulation-

2007-07-23
2007-01-1850
An experimental and numerical study was conducted on the spray and mixture properties of a hole-type injector for direct injection (D. I.) gasoline engines. The Laser Absorption Scattering (LAS) technique was adopted to simultaneously measure the spatial concentration distributions and the mass of the liquid and vapor phases in the fuel spray injected into a high-pressure and high-temperature constant volume vessel. The experimental results were compared to the numerical calculation results using three-dimensional CFD and the multi-objective optimization. In the numerical simulation, the design variable of the spray model was optimized by choosing spray tip penetration, and mass of liquid and vapor phases as objective functions.
Technical Paper

Spray and Evaporation Characteristics of Multi-Hole Injector for DISI Engines - Effect of Diverging Angle Between Neighboring Holes

2009-04-20
2009-01-1500
Experimental and computational studies were carried out to characterize the spray development and evaporation processes of multi-hole injector for direct injection spark ignition (DISI) engines. The main injector parameter to be investigated in this study is a diverging angle between neighboring two holes. In the experimental study, the influence of the diverging angle on evaporation process of fuel spray from two-hole injector was investigated using Laser Absorption Scattering (LAS) measurement. Smaller diverging angle causes larger spray tip penetration because the momentum of the spray from one hole emphasizes another, when two spray merge to one. Moreover, spray tip penetration decreases at certain diverging angle due to the negative pressure region between two sprays. Mechanisms behind the above spray behaviors were discussed using the detailed information on the spray and ambient gas flow fields obtained by the three dimensional computational fluid dynamics (CFD).
Journal Article

Characteristics of Evaporating Diesel Spray: A Comparison of Laser Measurements and Empirical/Theoretical Predictions

2009-04-20
2009-01-0854
The objective of the paper is to characterize the diesel spray under the ambient conditions relevant for direct injection (D.I.) diesel engines. The particular emphasis is on the comparisons between laser measurements and predictions by empirical correlations and theoretical analyses. The ultraviolet-visible laser absorption-scattering (LAS) imaging technique is employed to quantitively determine the spray/mixture properties of the diesel spray injected by a hole-type injector, in terms of spray tip penetration and spatial concentration distributions of liquid and vapor phase. The structure of evaporating spray is obtained and analyzed. Based on the penetration correlations in the literature, a non-dimensional analysis of the spray tip penetration data is carried out. The results indicate that a self-similar state of the evaporating fuel spray is achieved.
Technical Paper

An Insight Into Effect of Split Injection on Mixture Formation and Combustion of DI Gasoline Engines

2004-06-08
2004-01-1949
In the previous study of the authors, it was found that some benefits for the mixture preparation of DI gasoline engines can be offered by splitting the fuel injection, such as the phenomenon of high density liquid phase fuel piling up at the leading edge of the spray can be circumvented. In a further analysis, the vapor quantity in the “stable operating” range (equivalence ratio of vapor ϕv in a range of 0.7≤ϕv≤1.3) was significantly increased by the split injection compared to the single injection. In this work, the mechanism of the effect of the split injection on the mixture formation process was studied by combining the laser-sheet imaging, LIF-PIV and the LAS (Laser Absorption Scattering) technique. As a result, it is found that the spray-induced ambient air motion can help the formation of the more combustible mixture of the split injection whereas it played a minus role of diluting the spray by the single injection.
Technical Paper

An Analysis of Droplets and Ambient Air Interaction in a D.I. Gasoline Spray Using LIF-PIV Technique

2002-03-04
2002-01-0743
Measurements of the droplet and ambient air velocities in and around a D.I. gasoline spray were made by combining the laser induced fluorescence (LIF) and the particle image velocimetry (PIV) techniques. Before the fuel spray was injected into a constant volume vessel, rhodamine B-water solution was injected into the ambient air by a swirl-type injector for dispersing the fine fluorescent liquid particles as tracers for the ambient air motion. The fuel spray was injected into the fluorescent tracer clouds by a D.I. gasoline injector and was illuminated by an Nd:YAG laser light sheet (wave length: 532 nm). The light scattered by the droplets in the fuel spray was the same as the Nd:YAG laser wavelength, whereas the light emitted by the fluorescent tracer clouds was at a longer wavelength.
Technical Paper

Simultaneous Flow Field Measurement of D.I. Gasoline Spray and Entrained Ambient Air by LIF-PIV Technique

2003-03-03
2003-01-1115
The spray and the entrained ambient air motions produced by a swirl-type D.I. gasoline injector were simultaneously measured by combining the laser induced fluorescence (LIF) and the particle image velocimetry (PIV) techniques. For the simultaneous measurement of the spray and the ambient air velocities, the succeeding two image pairs of the fuel spray and the ambient air tracer particles were captured by using a Nd:YAG laser light sheet (wave length: 532 nm) and two high-resolution CCD cameras. The light emitted from the fluorescent tracer clouds was discriminated from the light scattered from the droplets in the fuel spray by an optical low-pass filter (>560 nm), and the Mie scattering signals from the spray particles were screened by a band-pass filter ranging from 520 to 545 nm. The spray and the tracer particle images were analyzed by the double frame cross-correlation PIV technique to obtain the droplets and ambient air velocity distributions.
Technical Paper

Characterization of Mixture Formation Processes in D.I. Gasoline Sprays by the Laser Absorption Scattering (LAS) Technique - Effect of Injection Conditions

2003-05-19
2003-01-1811
Mixture formation processes play a vital role on the performance of a D.I. Gasoline engine. Quantitative measurement of liquid and vapor phase concentration distribution in a D.I. gasoline spray is very important in understanding the mixture formation processes. In this paper, an unique laser absorption scattering (LAS) technique was employed to investigate the mixture formation processes of a fuel spray injected by a D.I. gasoline injector into a high pressure and temperature constant volume vessel. P-xylene, which is quite suitable for the application of the LAS technique, was selected as the test fuel. The temporal variations of the concentration distribution of both the liquid and vapor phases in the spray were quantitatively clarified. Then the effects of injection pressure and quantity on the concentration distributions of both the liquid and vapor phases in the spray were analyzed.
Technical Paper

Fuel Spray Simulation of High-Pressure Swirl-Injector for DISI Engines and Comparison with Laser Diagnostic Measurements

2003-03-03
2003-01-0007
A comprehensive model for sprays emerging from high-pressure swirl injectors in DISI engines has been developed accounting for both primary and secondary atomization. The model considers the transient behavior of the pre-spray and the steady-state behavior of the main spray. The pre-spray modeling is based on an empirical solid cone approach with varying cone angle. The main spray modeling is based on the Liquid Instability Sheet Atomization (LISA) approach, which is extended here to include the effects of swirl. Mie Scattering, LIF, PIV and Laser Droplet Size Analyzer techniques have been used to produce a set of experimental data for model validation. Both qualitative comparisons of the evolution of the spray structure, as well as quantitative comparisons of spray tip penetration and droplet sizes have been made. It is concluded that the model compares favorably with data under atmospheric conditions.
Technical Paper

Spray, Mixture and Combustion Characteristics of Small Injection Amount Fuel Spray Injected by Hole Nozzle for Diesel Engine

2016-11-08
2016-32-0064
The injection amount per stage in a multiple injection strategy is smaller than a conventional single-stage injection. In this paper, the effect of the injection amount (0.27mg, 0.89mg, 2.97mg) under 100MPa injection pressure and the effect of injection pressure (100MPa, 150MPa, 170MPa) under different injection amounts (0.27mg, 2.97mg) on the spray and mixture formation characteristics were studied by analyzing the vapor/liquid phase concentration distributions obtained under various conditions via using the tracer LAS technique. The spray was injected into a high-pressure and high-temperature constant volume vessel by using a single-hole nozzle with a diameter 0.133mm. The higher the injection pressure with a smaller injection amount is, the shorter the spray tip penetration and leaner air-fuel mixture occur. The combustion processes had been examined by a high-speed video camera with the two-color pyrometry method.
Technical Paper

Quantitative Measurement of Droplets and Vapor Concentration Distributions in Diesel Sprays by Processing UV and Visible Images

2001-03-05
2001-01-1294
In order to measure the droplets and vapor concentration inside a fuel spray, a dual-wavelength laser absorption-scattering technique was developed using the second harmonic (532nm) and the fourth harmonic (266nm) of a Nd:YAG laser and using dimethylnaphthalene as the test fuel. The investigation results show that dimethylnaphthalene, which has physical properties similar to diesel fuel, is almost transparent to visible light near 532nm and is a strong absorber of ultraviolet light near 266nm. Based on this result, the vapor concentration in a fuel spray can be determined by the two separate measurements: a transmission measurement at a non-absorbing wavelength to detect the droplets optical thickness and a transmission measurement at an absorbing wavelength to detect the joint vapor and droplets optical thickness. The droplets density can be determined by extinction imaging through the transmission at the non-absorbing wavelength.
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