Publications
227 results found
Hardalupas I, Hong CH, Keramiotis CH, et al., 2016, Towards identifying flame patterns in multiple, late injection schemes on a single cylinder optical diesel engine, Combustion Science and Technology, Vol: 188, Pages: 2217-2235, ISSN: 1563-521X
The work investigates the effect of various post-injection strategies on the flame patterns in a RicardoHydra optical single cylinder light duty diesel engine, operated in a partially premixed combustionmode (PPC), under low load (IMEP: ca. 2.3 bar) low speed (1200 rpm) conditions. The effect of postinjectionfuel amount (12 and 24% of the total fuel quantity per cycle) and post-injection timing (0,5, 10 deg aTDC) are investigated via pressure trace analysis and optical measurements. Flamepropagation is captured by means of high speed flame natural luminosity imaging and of CH*, C2*and OH*line-of-sight chemiluminescence measurements. Results indicate that post-injectionssuppress mixture reactivity but enhances oxidation, and that a larger amount of fuel and/or later postinjection, leads to higher levels of natural luminosity, indicating possible higher soot-out emissions,while post injection close to the main combustion event appears to have a beneficial effect on the sootoxidation processes.
Hardalupas I, Ramaswamy KG, Taylor AMKP, et al., 2016, Effect of Dwell Time on Liquid Penetration of Multiple Injection Diesel Sprays in a Constant Volume Chamber, 27th Annual Conference on Liquid Atomization and Spray Systems
Hardalupas I, Nikita C, Taylor AM, et al., 2016, Experimental Validation of Pressure Loss Models under Pulsating Conditions in three way Junctions, THIESEL 2016 Conference on Thermo- and Fluid Dynamic Processes in Direct Injection Engines
Hardalupas I, Hong C, Taylor AM, 2016, IGNITION DELAY AND BURN DURATION OF REFINERY BASED FUELS IN A CONSTANT VOLUME VESSEL AT DIESEL ENGINE CONDITION, 36th FISITA World Automotive Congress
Hardalupas I, Stetsyuk V, Soulopoulos N, et al., 2016, Scalar dissipation rate statistics in turbulent swirling jets, Physics of Fluids, Vol: 28, ISSN: 1089-7666
The scalar dissipation rate statistics were measured in an isothermal flow formed by discharging a central jet in an annular stream of swirling air flow. This is a typical geometry used in swirl-stabilised burners, where the central jet is the fuel. The flow Reynolds number was 29 000, based on the area-averaged velocity of 8.46 m/s at the exit and the diameter of 50.8 mm. The scalar dissipation rate and its statistics were computed from two-dimensional imaging of the mixture fraction fields obtained with planar laser induced fluorescence of acetone. Three swirl numbers, S, of 0.3, 0.58, and 1.07 of the annular swirling stream were considered. The influence of the swirl number on scalar mixing, unconditional, and conditional scalar dissipation rate statistics were quantified. A procedure, based on a Wiener filter approach, was used to de-noise the raw mixture fraction images. The filtering errors on the scalar dissipation rate measurements were up to 15%, depending on downstream positions from the burner exit. The maximum of instantaneous scalar dissipation rate was found to be up to 35 s−1, while the mean dissipation rate was 10 times smaller. The probability density functions of the logarithm of the scalar dissipation rate fluctuations were found to be slightly negatively skewed at low swirl numbers and almost symmetrical when the swirl number increased. The assumption of statistical independence between the scalar and its dissipation rate was valid for higher swirl numbers at locations with low scalar fluctuations and less valid for low swirl numbers. The deviations from the assumption of statistical independence were quantified. The conditional mean of the scalar dissipation rate, the standard deviation of the scalar dissipation rate fluctuations, the weighted probability of occurrence of the mean conditional scalar dissipation rate, and the conditional probability are reported.
Bergeles K, Charalampous G, Hardalupas I, et al., 2016, Breakup of non-spherical droplets, 27th Annual Conference on Liquid Atomization and Spray Systems
Bergeles K, Hardalupas I, Kawaguchi T, et al., 2016, Application of Plenoptic Imaging in Multiphase Flows, 18th Int Symp on Applications of Laser Techniques to Fluid Mechanics
Pearce D, Hardalupas I, Taylor AM, 2016, Laser imaging of pressure waves and cavitation generated by diesel fuel injector jets in a model of an injection rate meter, 18th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics
Nikita C, Hardalupas I, Taylor AM, 2016, Study of Pulsating Flow in three way exhaust manifolds junctions through PIV, 18th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics
Shi Z, Hardalupas I, Taylor AM, 2016, Local equivalence ratio measurement in opposed jet premixed and non-premixed methane-air flames using laser-induced breakdown spectroscopy, 18th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics
Hardalupas I, Sahu S, Taylor AMKP, 2016, Droplet-turbulence interaction in a confined polydispersed spray: effect of turbulence on droplet dispersion, Journal of Fluid Mechanics, Vol: 794, Pages: 267-309, ISSN: 1469-7645
The effect of entrained air turbulence on dispersion of droplets (with Stokes numberbased on Kolmogorov time scale, Stη, of the order of 1) in a polydispersed spray isexperimentally studied through simultaneous and planar measurements of droplet size,velocity, and gas flow velocity (Hardalupas et al. 2010). The preferential accumulation ofdroplets at various measurement locations in the spray was examined by two independentmethods viz. counting droplets on images by dividing the image in to boxes of differentsizes, and by estimating the radial distribution function (RDF). The dimension of dropletclusters (obtained by both approaches) was of the order of Kolmogorov’s length scaleof the fluid flow implying the significant influence of viscous scales of the fluid flowon cluster formation. The RDF of different size classes indicated an increase in clusterdimension for larger droplets (higher Stη). The length scales of droplet clusters increasedtowards the outer spray regions, where the gravitational influence on droplets is strongercompared to the central spray locations. The correlation between fluctuations of dropletconcentration and, droplet and gas velocities were estimated and found to be negativenear the spray edge, while it was close to zero at other locations. The probability densityfunction of slip between fluctuating droplet velocity and gas velocity ‘seen’ by the dropletssignified presence of considerable instantaneous slip velocity, which is crucial for dropletgasmomentum exchange. In order to investigate different mechanisms of turbulencemodulation of the carrier phase, the three correlation terms in the turbulent kineticenergy equation for particle-laden flows (Chen & Wood 1985) are evaluated conditionalon droplet size classes. Based on the comparison of the correlation terms, it is recognizedthat though the inter-phase energy transfer due to fluctuations of droplet concentrationis low compared to the energy exchange only due
Henkel S, Beyrau F, Hardalupas I, et al., 2016, Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces, Optics Express, Vol: 24, Pages: 2542-2561, ISSN: 1094-4087
This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.
Soulopoulos N, Hardalupas Y, Taylor AMKP, 2015, Mixing and scalar dissipation rate statistics in a starting gas jet, Physics of Fluids, Vol: 27, Pages: 1-24, ISSN: 1070-6631
We quantify the temporal development of the mixing field of a starting jet by measuring the mixture fraction and the scalar dissipation rate and their statistics in an isothermal, impulsively started, gaseous jet. The scalar measurements are performed using planar laser induced fluorescence and, with appropriate processing of the resulting images, allow scalar dissipation rate measurements within 20%. The probability density functions of the mixture fraction, measured within a region of the order of 3 times the Batchelor length scale of the flow, are bimodal and skewed around a well-mixed radial location, which depends on the downstream distance and the time after the start of injection. The instantaneous distributions of the scalar dissipation rate reveal regions of high mixing at the jet periphery and at the developing vortex ring. The normalised probability density function (pdf) of the scalar dissipation rate at various flow positions and times after the start of injection has the same characteristic shape but differs from the usually suggested lognormal distribution at both low and high dissipation values; the same, also, holds true for the pdf conditioned on different values of the mixture fraction. The mean of the scalar dissipation rate conditional on mixture fraction shows a variation across the mixture fraction range, which differs between flow locations and times after the start of injection; however, at later times and for larger downstream distances the conditional mean between flow locations has similar distributions. Implications of the measurements for the auto-ignition of gaseous jets are examined and demonstrate that near the nozzle exit or at earlier times conditions are un-favourable for auto-ignition.
Pearce D, Hardalupas Y, Taylor AMKP, 2015, Near Nozzle Field Conditions in Diesel Fuel Injector Testing, SAE Technical Paper Series, Vol: 2015, ISSN: 0148-7191
The measurement of the rate of fuel injection using a constant volume, fluid filled chamber and measuring the pressure change as a function of time due to the injected fluid (the so called “Zeuch” method) is an industry standard due to its simple theoretical underpinnings. Such a measurement device is useful to determine key timing and quantity parameters for injection system improvements to meet the evolving requirements of emissions, power and economy. This study aims to further the understanding of the nature of cavitation which could occur in the near nozzle region under these specific conditions of liquid into liquid injection using high pressure diesel injectors for heavy duty engines. The motivation for this work is to better understand the temporal signature of the pressure signals that arise in a typical injection cycle.A preliminary CFD study was performed, using OpenFOAM, with a transient (Large Eddy Simulation -LES), multiphase solver using the homogenous equilibrium model for the compressibility of the liquid/vapour. The nozzle body was modelled for simplicity without the nozzle needle using a nozzle hole of 200μm diameter and the body pressurised to values typical for common rail engines. Temperature effects were neglected and the wall condition assumed to be adiabatic. The chamber initial static pressure was varied between 10 and 50 bar to reflect typical testing conditions.Results indicate that vapour formation could occur in areas 10-30mm distant from the nozzle itself. The cavitation was initiated around 100 μs after the jet had started for low ΔP cases and followed the development period required for the formation of vortices associated with the vortex roll up of this jet. These vortices had localised sites, in their core region, below the vapour pressure and were convected downstream of their initial formation location. It was also found that vapour formation could occur at chamber static pressures up to 50 bar (the highes
Founti M, Hardalupas Y, Hong C, et al., 2015, An Experimental Investigation on the Effect of Diluent Addition on Flame Characteristics in a Single Cylinder Optical Diesel Engine, 12th International Conference on Engines & Vehicles, Publisher: Society of Automotive Engineers, ISSN: 0148-7191
The present work investigates the effect of low levels CO2 addition on the combustion characteristics inside a single cylinder optical engine operated under low load conditions. The effects of dilution levels (up to 7.5% mass flow rate CO2 addition), the number of pilot injections (single or double pilot injections) and injection pressure (25 or 40 MPa), are evaluated towards the direction of achieving a partially premixed combustion (PPC) operation mode. The findings are discussed based on optical measurements and via pressure trace and apparent rate of heat release analyses in a Ricardo Hydra optical light duty diesel engine. The engine was operated under low IMEP levels of the order of 1.6 bar at 1200 rpm and with a CO2 diluent-enhanced atmosphere resembling an environment of simulated low exhaust gas recirculation (EGR) rates. Flame propagation is captured by means of high speed imaging and OH, CH and C2 line-of-sight chemiluminescence respectively. Each of the above species is a proxy of a fundamental combustion property; OH* is related to the oxidation zone, CH* to the heat release zone and the flame front, while C2* is indicative of fuel-rich areas. The combined analyses of the obtained results were made under the perspective of identifying the induced alterations in flame structures and, possibly, combustion modes, and their manifestation at the global in-cylinder conditions. The increase of CO2 addition results in lower peak pressures and in an overall delay of the combustion process, while also influences the spatial characteristics of reaction and oxidation zones, as well as differentiates the extent of fuel-rich pockets. Multiple injections advance the main combustion event and an increase in injection pressure enhances fuel evaporation and mixing while spatially confining the observed flame structures. Overall, operation under relatively slightly diluted conditions with more pilot injection events at higher rail pressure appear to enhance mixing, provin
Nikita C, Hardalupas Y, Taylor A, 2015, Study of Pressure Losses of Unsteady Compressible Flows in Three- Way Junctions, 12th International Conference on Engines & Vehicles, Publisher: SAE
The aim of this paper is to extend the evaluation of the accuracy of published 1-D pressure loss coefficients which are used in 1-D gas dynamics models, in unsteady compressible flows propagating in the exhaust pulses in manifolds. These pressure loss coefficients were derived from the conservation of linear momentum over finite control volumes based on assumptions including steady flow. The objectives of this work were to evaluate the accuracy of the pressure loss coefficients over the type of flows generated by engine-like pressure pulses propagating in a range of three-pipe junctions. The evaluation was performed by reference to results from unsteady, compressible, 3-D Reynolds-averaged computational fluid dynamic (CFD - open source software OpenFOAM) simulations. Two of the junction branches represented the exhaust pipes from two cylinders and the remaining was the outlet pipe. All pipes had a diameter of 25mm with length ratio 1:2 between inlet and outlet. Y junctions of 30°and 60°degrees and a T junction of 60°were tested with a blow-down 1.8bar isothermal pulse at 45Hz as the inlet boundary condition. The results have shown that the temporal pressure loss 'signal', as calculated between stations 5 diameters away of each of the junction ends, has also the shape of a pulse. The discrepancies observed with the 1D model occur at the beginning of the pulse and during the deceleration phase for all three geometries tested. For the Y30°discrepancies also occurred in the intermediate regions leading to less satisfactory results.
Sponfeldner T, Soulopoulos N, Beyrau F, et al., 2015, The structure of turbulent flames in fractal- and regular-grid-generated turbulence, Combustion and Flame, Vol: 162, Pages: 3379-3393, ISSN: 0010-2180
This study reports on the use of fractal grids as a new type of turbulence generators in premixed combustion applications. Fractal grids produce turbulence fields which differ from those formed by regular turbulence generators such as perforated plates or meshes. Fractal grids generate high turbulence intensities over an extended region some distance downstream of the grid with a comparatively small pressure drop. Additionally, the integral scale of the flow does not change downstream of the grid. The extended region of high turbulence can also be optimized for the specific application at hand by changing certain parameters of the grid which makes it possible to design the downstream development of the turbulence field. Four space-filling fractal square grids were designed to independently vary the resulting turbulent field and a regular square mesh grid with similar turbulent intensity acted as a reference case. The structure of the resulting premixed V-shaped flames was investigated using Conditioned Particle Image Velocimetry (CPIV). At the same downstream position, flames in the turbulence field of fractal grids showed larger turbulent burning velocity compared to flames in regular grid generated turbulence. However, when compared for the same turbulence intensity, flames in fractal grid generated turbulence produced similar turbulent burning velocities compared to flames in regular grid generated turbulence. In particular, it could be shown that theories such as Taylor's theory of turbulent diffusivity and Damköhler's theory of premixed flame propagation, which were deduced from regular turbulence fields, adequately described the increase of effective flame surface area due to the increase in turbulence intensity. Using fractal grids allows the independent variation of the turbulent fluctuations, the integral length scale and the turbulent Reynolds number. An unexpected finding was that the burning velocity ratio, s t/s l was negligible influenced by the i
Stetsyuk V, Soulopoulos N, Hardalupas I, et al., 2015, Experimental assessment of presumed filtered density function models, Physics of Fluids, Vol: 27, Pages: 065107-1-065107-19, ISSN: 1070-6631
Measured filtered density functions (FDFs) as well as assumed beta distribution model of mixture fraction and “subgrid” scale (SGS) scalar variance z′′2⎯⎯⎯⎯⎯⎯⎯, used typically in large eddy simulations, were studied by analysing experimental data, obtained from two-dimensional planar, laser induced fluorescence measurements in isothermal swirling turbulent flows at a constant Reynolds number of 29 000 for different swirl numbers (0.3, 0.58, and 1.07). Two-dimensional spatial filtering, by using a box filter, was performed in order to obtain the filtered variables, namely, resolved mean and “subgrid” scale scalar variance. These were used as inputs for assumed beta distribution of mixture fraction and top-hat FDF shape estimates. The presumed beta distribution model, top-hat FDF, and the measured filtered density functions were used to integrate a laminar flamelet solution in order to calculate the corresponding resolved temperature. The experimentally measured FDFs varied with the flow swirl number and both axial and radial positions in the flow. The FDFs were unimodal at flow regions with low SGS scalar variance, z′′2⎯⎯⎯⎯⎯⎯⎯< 0.01, and bimodal at regions with high SGS variance, z′′2⎯⎯⎯⎯⎯⎯⎯> 0.02. Bimodal FDF could be observed for a filter size of approximately 1.5-2 times the Batchelor scale. Unimodal FDF could be observed for a filter size as large as four times the Batchelor scale under well-mixed conditions. In addition, two common computational models (a gradient assumption and a scale similarity model) for the SGS scalar variance were used with the aim to evaluate their validity through comparison with the experimental data. It was found that the gradient assumption model performed generally better than the scale similarity one.
Aleiferis P, Charalambides A, Hardalupas Y, et al., 2015, Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine, Applied Optics, Vol: 54, Pages: 4566-4579, ISSN: 1559-128X
Charalambides AG, Hardalupas Y, Soulopoulos N, et al., 2015, Using Infrared Laser Absorption to Measure Hydrocarbon Concentration in a Lean-Burn, Stratified-Charge, Spark-Ignition Engine, Combustion Science and Technology, Vol: 187, Pages: 679-696, ISSN: 1563-521X
The operating range of lean-burn spark-ignition (SI) engines is limited by the cycle-to-cycle variability of the fuel concentration at or near the spark plug at ignition timing. An experimental investigation was undertaken to measure the temporal and spatial distribution of hydrocarbon (HC) concentration in a spark-ignition engine, using the infrared (IR) laser absorption at 3392 nm. The purposes were to establish whether there is a correlation between time-resolved HC measurements for a range of global air-to-fuel (A/F) ratios (A/F = 15.5–23) with the strength of the firing stroke and to establish how this varies with fuel port-injection strategies against either open (injection timing 30° crank angle (CA) after intake top dead center) or closed-valves (injection timing 180°CA after intake top dead center), respectively resulting in stratified and near-homogeneous charge distributions. The results showed that IR line-of-sight (LOS) averaged A/F ratio measurements yielded a good agreement with the global A/F ratio readings obtained by the linear air-to-fuel (LAF) zirconia-based sensor. Furthermore, the cyclic variability of the measurements of the fuel concentration increased with increasing A/F ratio. At A/F = 23, closed-valve injection strategy resulted in small spatial stratification of the fuel charge with an ensemble-averaged correlation coefficient of fluctuations of the IR LOS A/F ratios with fluctuations of peak in-cylinder pressure of 0.37. For open-valve injection strategy, which resulted in axial fuel mixture charge-stratification but no radial charge-stratification, a maximum correlation coefficient of the IR LOS A/F ratios with fluctuations of peak pressure of 0.34 was measured (at the measurement location closest to the spark). This correlation was reduced to 0.17 at locations furthest from the spark plug. Finally, results showed that at A/F = 23, fuel stratification can be used to control lean-burn SI combustion, while at A/F = 15.5, no
Sponfeldner T, Boxx I, Beyrau F, et al., 2015, On the alignment of fluid-dynamic principal strain-rates with the 3D flamelet-normal in a premixed turbulent V-flame, Proceedings of the Combustion Institute, Vol: 35, Pages: 1269-1276, ISSN: 0082-0784
Statistics of the alignment of fluid-dynamic principal strain-rates and the local flamelet-normal in a premixed turbulent V-flame (methane-air, Ret = 450, φ = 0.8) were measured experimentally using simultaneous stereoscopic particle image velocimetry (SPIV) and planar laser-induced fluorescence of OH (OH-PLIF). The use of a second OH-PLIF sheet, oriented in a crossed-plane imaging configuration enabled conditioning of the statistics with respect to through-plane flame orientation. The statistics show the geometric alignment changes significantly with the distance between the flame and the location where the strain-rate field is evaluated. It was observed that approximately 30 η upstream of the flame, the fluid-dynamic principal strain-rates show no preferential alignment with the flamelet. With increasing proximity to the flame, the most extensive principal strain-rate is observed to align preferentially perpendicular to the local flamelet-normal. In the immediate vicinity of the flame, where local fluid-dynamics are dominated by dilatation, the principal extensive strain-rate is observed to align preferentially parallel to the local flamelet-normal. The realignment of the principal strain-rates in the immediate vicinity of the flame is clearly the result of local flow acceleration caused by heat-release at the reaction zone. As the most extensive principal strain-rate tends to align preferentially perpendicular to the local flamelet-normal outside the region of heat-release, the data indicate that high scalar gradients observed ahead of the flamelet are produced by the local turbulent flow-field, rather than destroyed by it.
Sahu S, Hardalupas Y, Taylor AMKP, 2015, Experimental spray characterization for a double swirl coaxial air blast atomizer
The present research reports an experimental spray characterization of a generic double-swirl prefilming model aeroengine atomizer, which injects an annular liquid sheet of 0.5 mm thickness at the nozzle exit, sandwiched between an inner and an outer co-rotating swirling air streams. Planar spray measurements are obtained using a non-invasive laser-based Interferometric Laser Imaging Droplet Sizing (ILIDS) technique1, 2, which is capable of providing simultaneous planar measurements of droplet size, velocity and number density in the resulting spray. Experiments are reported for a water spray for different axial (Z) and radial (R) locations for different air and water flow conditions. Apart from time-averaged droplet size and velocity measurements, ILIDS allows unique measurements of other important statistical quantities, including droplet-droplet spatial velocity correlation, which is important for evaluation of new modeling approaches for the droplet fluctuating motion, and is presented here for different separation distances between droplets and conditional on droplet size. In addition the extent of droplet clustering for different droplet size classes is presented and the corresponding cluster dimensions quantified, as estimated from the radial distribution function5 (RDF) measured conditional on droplet size classes. Finally, measurements of mean and fluctuations of droplet number density for different droplet size classes are reported. The new physical understanding of the spray dynamics and droplet cluster formation in sprays, provided by the novel measured quantities, is discussed.
Soulopoulos N, Hardalupas Y, Taylor AMKP, 2014, Scalar dissipation rate measurements in a starting jet, EXPERIMENTS IN FLUIDS, Vol: 55, ISSN: 0723-4864
- Author Web Link
- Cite
- Citations: 12
Sahu S, Hardalupas Y, Taylor AMKP, 2014, Droplet–turbulence interaction in a confined polydispersed spray: effect of droplet size and flow length scales on spatial droplet–gas velocity correlations, Journal of Fluid Mechanics, Vol: 741, Pages: 98-138, ISSN: 0022-1120
This paper discusses the interaction between droplets and entrained turbulent air flow in the far-downstream locations of a confined polydispersed isothermal spray. Simultaneous and planar measurements of droplet and gas velocities in the spray along with droplet size are obtained with the application of a novel experimental technique, developed by Hardalupas et al. (Exp. Fluids, vol. 49, 2010, pp. 417–434), which combines interferometric laser imaging for droplet sizing (ILIDS) with particle image velocimetry (PIV). These measurements quantified the spatial correlation coefficients of droplet–gas velocity fluctuations ( Rdg ) and droplet–droplet velocity fluctuations ( Rdd ) conditional on droplet size classes, for various separation distances, and for axial and cross-stream velocity components. At the measurement location close to the spray edge, with increasing droplet size, Rdg was found to increase in axial direction and decrease in cross-stream direction. This suggests that as the gas-phase turbulence becomes more anisotropic away from the spray axis, the gravitational influence on droplet–gas correlated motion tends to increase. The effective length scales of the correlated droplet–gas motion were evaluated and compared with that for gas and droplet motion. The role of different turbulent eddies of the gas flow on the droplet–gas interaction was examined. The flow structures were extracted using proper orthogonal decomposition (POD) of the instantaneous gas velocity data, and their contribution on the spatial droplet–gas velocity correlation was evaluated, which quantified the momentum transfer between the two phases at different length scales of the gas flow. The droplets were observed to augment turbulence for the first three POD modes (larger scales) and attenuate it for the rest of the modes (smaller scales). It has been realized that apart from droplet Stokes number and mass loading, the dynamic range of length s
Sahu S, Hardalupas Y, Taylor AMKP, 2014, Simultaneous droplet and vapour-phase measurements in an evaporative spray by combined ILIDS and PLIF techniques, EXPERIMENTS IN FLUIDS, Vol: 55, ISSN: 0723-4864
- Author Web Link
- Cite
- Citations: 21
Garcia-Armingol T, Hardalupas Y, Taylor AMKP, et al., 2014, Effect of local flame properties on chemiluminescence-based stoichiometry measurement, EXPERIMENTAL THERMAL AND FLUID SCIENCE, Vol: 53, Pages: 93-103, ISSN: 0894-1777
- Author Web Link
- Cite
- Citations: 22
Hardalupas Y, Taylor AMKP, Zarogoulidis K, 2014, Detection and evaluation of droplet and bubble fringe patterns in images of planar interferometric measurement techniques using the wavelet transform, International Conference on Optical Particle Characterization (OPC 2014), Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
- Author Web Link
- Cite
- Citations: 2
Soulopoulos N, Kerl J, Sponfeldner T, et al., 2013, Turbulent premixed flames on fractal-grid-generated turbulence, FLUID DYNAMICS RESEARCH, Vol: 45, ISSN: 0169-5983
- Author Web Link
- Cite
- Citations: 20
Kalghatgi GT, Gurubaran RK, Davenport A, et al., 2013, Some advantages and challenges of running a Euro IV, V6 diesel engine on a gasoline fuel, FUEL, Vol: 108, Pages: 197-207, ISSN: 0016-2361
- Author Web Link
- Cite
- Citations: 51
Katsikadakos D, Zhou C-W, Simmie JM, et al., 2013, Rate constants of hydrogen abstraction by methyl radical from <i>n</i>-butanol and a comparison of CanTherm, MultiWell and Variflex, PROCEEDINGS OF THE COMBUSTION INSTITUTE, Vol: 34, Pages: 483-491, ISSN: 1540-7489
- Author Web Link
- Cite
- Citations: 16
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.