Measurement of Sauter mean diameter in diesel sprays using a scattering–absorption measurement ratio technique

Abstract

A new diagnostic for the quantification of Sauter mean diameter in high-pressure fuel sprays has been recently developed using combined optical and X-ray measurements at the Georgia Institute of Technology and Argonne National Laboratory, respectively. This diagnostic utilizes liquid scattering extinction measurements from diffuse back-illumination imaging, conducted at Georgia Tech, and liquid absorption measurements from X-ray radiography, conducted at Argonne's Advanced Photon Source. The new diagnostic, entitled the scattering-absorption measurement ratio, quantifies two-dimensional distributions of path-integrated Sauter mean diameter, enabling the construction of the spatial history of drop size development within practical fuel sprays. This technique offers unique benefits over conventional drop-sizing methods in that it can be more robust in optically dense regions of the spray, while also providing high spatial resolution of the corresponding droplet field. The methodology for quantification of Sauter mean diameter distributions using the scattering-absorption measurement ratio technique has been previously introduced and demonstrated in diesel sprays using the Engine Combustion Network Spray D injector; however, a more detailed treatment of measurement uncertainties has been needed. In this work, we present a summary of the various sources of measurement uncertainty in the scattering-absorption measurement ratio diagnostic, like those due to the experimental setup, data processing methods, and theoretical assumptions, and assess how these sources of uncertainty affect the quantified Sauter mean diameter. The spatially resolved Sauter mean diameter measurements that result from the scattering-absorption measurement ratio diagnostic will be especially valuable to the engine modeling community for the quantitative validation of spray submodels in engine computational fluid dynamics codes. Careful evaluation and quantification of measurement uncertainties are important to support accurate model validation and to ensure the development of more predictive spray models.

Examination of diesel spray combustion in supercritical ambient fluid using large-eddy simulations

“…Various experiments have been performed under Engine Combustion Network 1 (ECN) Spray A [2][3][4][5][6][7][8] and Spray D [9][10][11][12][13][14][15][16][17][18] target conditions in order to contribute to the understanding of diesel combustion. In addition, Reynolds-Averaged Navier-Stokes (RANS) and largeeddy simulations (LES) have been used to simulate Spray A [19][20][21][22][23][24][25][26][27][28][29][30][31] and Spray D 15,[32][33][34] in computational investigations.…”

A multispectral, extinction-based diagnostic for drop sizing in optically dense diesel sprays

“…SAMR and USAXS data are extracted from Martinez and colleagues. 21,27 Note that SAMR90 and SAMR165 present distributions corresponding to injector orientations that are 90°and 165°out of phase with the installation used in the current work. This would cover the largest possible asymmetry in the spray field.…”

Editorial — ‘Thermo- and Fluid-Dynamic Processes in Direct Injection Engines’: THIESEL 2018 Special Issue by Xandra Margot

“…The paper selection covers all topics of the conference, reflecting current research trends, from the most traditional ones such as injection, sprays and combustion [1][2][3][4][5] to more recent pre-occupations such as studies to improve engine thermal management, [6][7][8] understanding the source of various emissions such as unburned hydrocarbons (UHC) and nanoparticles 9,10 or determining adequate gas exchange strategies for an efficient operation of exhaust after-treatment devices and for emission reduction in cold-start conditions. 11,12 Research on injection and sprays is still a hot topic, for diesel as well as gasoline direct injection (GDI) engines, as it is very relevant to understand the combustion process and the emissions.…”

“…11,12 Research on injection and sprays is still a hot topic, for diesel as well as gasoline direct injection (GDI) engines, as it is very relevant to understand the combustion process and the emissions. In fact, three of the works 1,4,5 included in this Special Issue have been developed in the frame of the Engine Combustion Network (ECN), an international collaborative work programme that aims at providing fundamental understanding of injection and combustion processes as well as reliable data for the validation of computational models.…”

“…Investigations in this field are therefore experimental as well as numerical, as illustrated in the first six papers selected for this edition. Martı´nez et al 1 assess the capabilities of the new scattering absorption measurement ratio (SAMR) technique to actually measure with adequate accuracy the Sauter mean diameter of spray droplets in order to support spray model development in computational fluid dynamic (CFD) codes. Rachakonda et al, 2 however, used CFD to study the effect of hole geometry, thermodynamic conditions of the fuel and ambient pressure on spray collapse in multi-hole GDI engines.…”