Studies of Swirl Burner Characteristics, Flame Lengths and Relative Pressure Amplitudes

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
A. Valera-Medina ◽  
N. Syred ◽  
P. Bowen ◽  
A. Crayford
Keyword(s):  
High Speed ◽  
Fossil Fuels ◽  
Fuel Injection ◽  
Flame Length ◽  
Swirl Flow ◽  
High Speed Photography ◽  
Relative Pressure ◽  
Fuel Injector ◽  
Swirl Burner ◽  
Potential Oscillations

Swirl stabilized combustion is a technology which, for stationary combustion, consumes more than 70 to 80% of the world’s fossil fuels. There have been many reviews of this technology, but there are still many gaps in understanding. This paper focuses on the general characteristics of a 100kW swirl burner, originally designed for poor quality fuels, in terms of flame characteristic, length and pressure fluctuations, to give a relative measure of the propensity of the system to respond to outside perturbations. Studied effects include swirl number, symmetry of the swirl flow system, type of fuel injector and mode of fuel injection. A range of techniques, including High Speed Photography (HSP), Particle Image Velocimetry (PIV) and fluctuating pressure measurements were used to create flame maps, flame length detail, and relative pressure amplitudes graphs. The results are discussed in the context of potential oscillations and coupling mechanisms including the effect of the precessing vortex core (PVC), recirculation and shear flow instabilities.

Experimental Characterization of Two-Phase Swirl Flow Interacting With a Circular Bluff Body

2021 ◽  
Author(s):  
Rafael Gonzalez Hernandez ◽  
Afshin Goharzadeh ◽  
Mahmoud Meribout ◽  
Lyes Khezzar
Keyword(s):  
High Speed ◽  
Bluff Body ◽  
Transition Period ◽  
Swirl Flow ◽  
Critical Distance ◽  
High Speed Photography ◽  
Flow Loop ◽  
Two Phase ◽  
Air Pocket ◽  
Air Core

Abstract This study presents an experimental investigation of two-phase swirl flow interacting with a circular bluff body. A horizontal and transparent multiphase flow loop is employed to investigate the dynamic of swirl flow close to the circular bluff body. Using high-speed photography, air-core development during the transition period is characterized. Analysis of both instantaneous and averaged images provides key information on air-core length and diameter for steady state conditions. The distance from air-core tip to the disk depends on a critical gas-liquid ratio (GLRc). The presence of air pocket behind the circular bluff body depends on a critical distance to the disk.

Characteristics of injection of diesel fuel, rapeseed oil and their mixtures in diesel engines of various types

2021 ◽  
pp. 167-178
Author(s):  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Diesel Engines ◽  
Rapeseed Oil ◽  
High Speed ◽  
Fuel Injection ◽  
Experimental Studies ◽  
Fuel Injector ◽  
High Speed Diesel ◽  
Engine Type

The necessity of adapting diesel engines to work on vegetable oils is justified. The possibility of using rapeseed oil and its mixtures with petroleum diesel fuel as motor fuels is considered. Experimental studies of fuel injection of small high-speed diesel engine type MD-6 (1 Ch 8,0/7,5)when using diesel oil and rapeseed oil and computational studies of auto-tractor diesel engine type D-245.12 (1 ChN 11/12,5), working on blends of petroleum diesel fuel and rapeseed oil. When switching autotractor diesel engine from diesel fuel to rapeseed oil in the full-fuel mode, the mass cycle fuel supply increased by 12 %, and in the small-size high-speed diesel engine – by about 27 %. From the point of view of the flow of the working process of these diesel engines, changes in other parameters of the fuel injection process are less significant. Keywords diesel engine; petroleum diesel fuel; vegetable oil; rapeseed oil; high pressure fuel pump; fuel injector; sprayer

Vortex ring-like structures in gasoline fuel sprays under cold-start conditions

2009 ◽  
Vol 10 (4) ◽  
pp. 195-214 ◽  
Author(s):  
S Begg ◽  
F Kaplanski ◽  
S Sazhin ◽  
M Hindle ◽  
M Heikal
Keyword(s):  
Vortex Ring ◽  
High Speed ◽  
Phenomenological Study ◽  
Theoretical Models ◽  
High Speed Photography ◽  
Fuel Injector ◽  
Fuel Injectors ◽  
Fuel Sprays ◽  
Phase Doppler Anemometry ◽  
Ring Model

A phenomenological study of vortex ring-like structures in gasoline fuel sprays is presented for two types of production fuel injectors: a low-pressure, port fuel injector (PFI) and a high-pressure atomizer that injects fuel directly into an engine combustion chamber (G-DI). High-speed photography and phase Doppler anemometry (PDA) were used to study the fuel sprays. In general, each spray was seen to comprise three distinct periods: an initial, unsteady phase; a quasi-steady injection phase; and an exponential trailing phase. For both injectors, vortex ring-like structures could be clearly traced in the tail of the sprays. The location of the region of maximal vorticity of the droplet and gas mixture was used to calculate the temporal evolution of the radial and axial components of the translational velocity of the vortex ring-like structures. The radial components of this velocity remained close to zero in both cases. The experimental results were used to evaluate the robustness of previously developed models of laminar and turbulent vortex rings. The normalized time, , and normalized axial velocity, , were introduced, where tinit is the time of initial observation of vortex ring-like structures. The time dependence of on was approximated as and for the PFI and G-DI sprays respectively. The G-DI spray compared favourably with the analytical vortex ring model, predicting , in the limit of long times, where α = 3/2 in the laminar case and α = 3/4 when the effects of turbulence are taken into account. The results for the PFI spray do not seem to be compatible with the predictions of the available theoretical models.

scholarly journals Influence of the Inner and Outer Secondary Air Ratios on the Combustion Characteristic and Flame Shape of a Swirl Burner with a Prechamber

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Pengzhong Liu ◽  
Fang Niu ◽  
Xuewen Wang ◽  
Fei Guo ◽  
Wei Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Combustion Efficiency ◽  
Flame Length ◽  
Combustion Characteristic ◽  
Swirl Burner ◽  
Free Zone ◽  
Combustion Experiment ◽  
Flame Shape ◽  
Secondary Air ◽  
Low Nitrogen

The swirl burner with a prechamber was used in a 14 MW pulverized-coal combustion experiment to investigate the influence of inner and secondary air ratios (ISA/OSA) on the combustion characteristic and flame shape in this work. The temperatures and species concentrations in the prechamber were measured via the flue gas analyzer and thermocouples. The flame shape beyond the prechamber outlet was captured by using a high-speed camera. The results showed that the combustion efficiency was increased and low nitrogen combustion was achieved by adopting the swirl burner with a prechamber. The high temperature corrosion and slagging phenomenon did not occur in the prechamber. The influence of ISA/OSA on temperature and species concentration profiles at different areas in the prechamber was different. The flame shape size exhibited an inflection point with increasing ISA/OSA. Considering, comprehensively, the temperature peak, near wall temperature, oxygen-free zone, CO concentration, flame length, flame diameter, and divergence angle, the case of ISA/OSA =1 : 2 had great processing on combustion efficiency and NOx emission. Thus, ISA/OSA = 1 : 2 was selected as the optimized case under experiment conditions.

scholarly journals Vortex flow and cavitation in diesel injector nozzles

2008 ◽  
Vol 610 ◽  
pp. 195-215 ◽  
Author(s):  
A. ANDRIOTIS ◽  
M. GAVAISES ◽  
C. ARCOUMANIS
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Fuel Injector ◽  
Flowing Liquid ◽  
Injection Quantity ◽  
Dimensional Reconstruction ◽  
Real Size

Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as ‘string-cavitation’. Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection events, implying significant hole-to-hole and cycle-to-cycle variations during the corresponding spray development.

Influence of Air and Fuel Mass Flow Fluctuations in a Premix Swirl Burner on Flame Dynamics

2006 ◽  
Author(s):  
M. P. Auer ◽  
C. Hirsch ◽  
T. Sattelmayer
Keyword(s):  
Heat Release ◽  
Mass Flow ◽  
High Speed ◽  
Structural Changes ◽  
Flame Structure ◽  
Flame Length ◽  
Turbulent Flames ◽  
Swirl Burner ◽  
Fuel Mass ◽  
Flame Dynamics

This paper discusses the structural changes observed in oscillating premixed turbulent swirling flames and demonstrates the influence of modulated mass flows on the flame dynamics in a preheated atmospheric test rig with a natural gas fired swirl burner. The experimentally investigated self excited and forced combustion oscillations of swirl stabilized premixed flames show varying time delays between the acoustically driven mass flow oscillations and the integral heat release rate of the flame. High speed films of the OH*-chemiluminescence reveal how the flame structure changes with the oscillation frequency and the phase angle between the fuel mass flow oscillation and the total mass flow at the burner exit. These parameters are found determine the spatial and temporal heat release distribution and thus the net heat release fluctuation. Therefore, the spatial and temporal heat release distribution along the flame length has an influence on the thermoacoustic coupling, even in the case of acoustically compact flames. The observed phenomena are discussed further using an 1-d analytical model. It underscores that for swirl stabilized premixed turbulent flames the dynamics of the flow field perturbation play a major role in creating the effective heat release fluctuation.

Analysis of the Influence of Pilot Injection Timing on Diesel Combustion in an Optical Engine by the Two-Color Method

2013 ◽  
Author(s):  
Weilin Zeng ◽  
Xu He ◽  
Senjia Jin ◽  
Hai Liu ◽  
Xiangrong Li ◽  
...  
Keyword(s):  
Ignition Delay ◽  
High Speed ◽  
Fuel Injection ◽  
Injection System ◽  
High Speed Photography ◽  
Injection Timing ◽  
Pilot Injection ◽  
Diesel Combustion ◽  
Optical Engine ◽  
Combustion Duration

High-speed photography, two-color method, and thermodynamic analysis have been used to improve understanding of the influence of pilot injection timing on diesel combustion in an optical engine equipped with an electronically-controlled, common rail, high-pressure fuel injection system. The tests were performed at four different pilot injection timings (30 degree, 25 degree, 20 degree, and 15 degree CA BTDC) with the same main injection timing (5 degree CA BTDC), and under 100MPa injection pressure. The engine speed was selected at 1200 rev/min, and the whole injection mass was fixed as 27.4 mg/stroke. The experimental results showed that the pilot injection timing had a strong influence on ignition delay and combustion duration: advancing the pilot injection timing turned to prolong the ignition delay and shorten the combustion duration. The combustion images indicated that when pilot injection was advanced, the area of luminous flames decreased. The results of two-color method suggested pilot injection timing significantly impacted both the soot temperature distribution and soot concentration (KL factor) within the combustion chamber. 30 degree CA BTDC was the optimal pilot injection timing for in-cylinder soot reduction.

scholarly journals Idling Performance under Valve Deactivation Strategy in Port Fuel Injection Engine

2019 ◽  
Vol 16 (4) ◽  
pp. 7155-7169
Author(s):  
A. S. Paimon ◽  
S. Rajoo ◽  
W. Jazair ◽  
M. A. Abas ◽  
Z. H. Che Daud
Keyword(s):  
Coefficient Of Variation ◽  
Engine Speed ◽  
Fuel Injection ◽  
Swirl Flow ◽  
Combustion Stability ◽  
Cylinder Pressure ◽  
Fuel Injector ◽  
Port Fuel Injection ◽  
Indicated Mean Effective Pressure ◽  
Significant Difference

This paper investigates the effect of valve deactivation (VDA) on idling performance in port fuel injection (PFI) engine. The test was conducted on 1.6L, 4-cylinder engine with PFI configuration. One of the two intake valves in each cylinder was deactivated (zero lift on deactivated port) and fuel injector was modified to only provide fuel spray on the active intake port. In-cylinder pressure was recorded by the combustion analyzer in order to measure and analyze the combustion characteristics. From the test, there are up to 6% of fuel consumption improvements across all the test conditions. Better combustion stability is achieved at very low idling speed (throttle position, TP = 2%) as a lower coefficient of variation of engine speed (COVrpm) and coefficient of variation indicated mean effective pressure (COVimep) were recorded. Increased intake velocity and swirl flow in the VDA strategy creates more turbulence intensity causing higher heat release rate and faster combustion. However, there is no significant difference in the pumping work during the intake cycle but there is extra pumping work recorded towards the end of expansion stroke due to the very early end of combustion. Therefore, valve deactivation strategy provides limited positive improvement to the idling performance in PFI engine.

Supersonic Injection of Gaseous Fuel Described as Possible Solution for NOx Emissions From Large-Bore Gas Engines

2002 ◽  
Author(s):  
Anatoli Borissov ◽  
James J. McCoy
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Experimental Testing ◽  
Nox Reduction ◽  
Engine Performance ◽  
Injection System ◽  
Fuel Injector ◽  
Modeling And Analysis ◽  
Jet Mixing ◽  
Supersonic Injection

Both physical and mathematical models were built to describe the main processes in large-bore gas engines. Based on the detail modeling and analysis of cylinder airflow, fuel injection, mixing, combustion and NOx generation, it was possible to pinpoint the problem of abnormal NOx production, even for lean mixtures, that occurs in these engines. In addition, analysis of the experimental data of jet mixing using high-speed photographic evidence, as well as engine performance data, has helped in the understanding of the mixing process. This has resulted in the development of a new way of the mixing of fuel and air utilizing multiple-nozzle supersonic injection. The fuel injection system is designed to optimize the mixing of the methane fuel with the air in the cylinder of a large bore natural gas engine. The design goals of low-pressure (<130 psi), all-electronic valve actuation, and optimal mixing were all achieved with a unique valve/nozzle arrangement. Later, a laser induced fluorescence method was used to take high-speed photographs of the development of the fuel jet exiting the newly developed supersonic electronic fuel injector (SSEFI). This result, together with the results of numerous experimental testing of SSEFI on different engines (GMVH-6, GMW-10, V-250, UTC-165) are presented as evidence of the success of the SSEFI application for the improvement of engine performance, engine control and NOx reduction.

The Simulation of Air Fuel Mixing in High Swirl Open Chamber Diesel Engines

1976 ◽  
Vol 190 (1) ◽  
pp. 503-513 ◽  
Author(s):  
C. J. Morris ◽  
J. C. Dent
Keyword(s):  
High Speed ◽  
Swirl Flow ◽  
High Speed Photography ◽  
Combustion System ◽  
Mixing Process ◽  
Fuel Jet ◽  
Mixing Parameter ◽  
Fuel Mixing ◽  
System Geometry ◽  
Good Agreement

SYNOPSIS The air fuel mixing process in the high swirl open chamber diesel engine is simulated by a steady state gas jet injected into a steady air swirl flow. The results from the simulation show good agreement with engine studies using high speed photography. An attempt to quantify fuel dispersion has been made through the introduction of a mixing parameter, which allows for combustion system geometry in addition to fuel jet and air swirl momenta.

Sign in / Sign up

Export Citation Format

Share Document