Time-resolved X-ray Tomography of Gasoline Direct Injection Sprays

Duke, Daniel J.; Swantek, Andrew; Sovis, Nicolas; Tilocco, F. Zak; Powell, Christopher F.; Kastengren, Alan L.; Gürsoy, Doğa; Biçer, Tekin

doi:10.4271/2015-01-1873

Cited by 38 publications

(17 citation statements)

References 27 publications

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“…Measuring the projected density at a few lines of sight is useful for modeling the density field of simple sprays such as those from a single-hole nozzle [21]. However, for a more detailed quantification of the density distribution of a more complicated spray structure such as one from a multi-hole injector, a full tomographic reconstruction can be implemented [1,7,22,23].…”

mentioning

confidence: 99%

A study on the relationship between internal nozzle geometry and injected mass distribution of eight ECN Spray G nozzles.

Matusik¹,

Duke²,

Sovis³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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Gasoline direct injection (GDI) nozzles are manufactured to meet geometric specifications with length scales on the order of a few hundred microns. The machining tolerances of these nominal dimensions are not always known due to the difficulty in accurately measuring such small length scales in a nonintrusive fashion. To gain insight into the variability of the machined dimensions as well as any effects that this variability may have on the fuel spray behavior, a series of measurements of the internal geometry and fuel mass distribution were performed on a set of eight nominally duplicate GDI "Spray G" nozzles provided by the Engine Combustion Network. The key dimensions of each of the eight nozzle holes were measured with micron resolution using full spectrum x-ray tomographic imaging at the 7-BM beamline of the Advanced Photon Source at Argonne National Laboratory. Fuel density distributions at 2 mm downstream of the nozzle tips were obtained by performing x-ray radiography measurements for many lines of sight. The density measurements reveal nozzle-to-nozzle as well as hole-to-hole density variations. The combination of high-resolution geometry and fuel distribution datasets allows spray phenomena to be linked to specific geometric characteristics of the nozzle, such as variability in the hole lengths and counterbore diameters, and the hole inlet corner radii. This analysis provides important insight into which geometrical characteristics of the nozzles may have the greatest importance in the development of the injected sprays, and to what degree these geometric variations might account for the total spray variability. The goal of this work is then to further the understanding of the relationship between internal nozzle geometry and fuel injection, provide input to improve computational models, and ultimately aid in optimizing injector design for higher fuel efficiency and lower emissions engines. KeywordsGDI, nozzle geometry, fuel spray density, fuel injector, DISI, Spray G, ECN, gasoline IntroductionTo fully realize the benefits of a gasoline direct injection (GDI) engine, precise control over the amount of injected fuel and the fuel-to-air mixing ratio is necessary. Any variations to the fuel spray distribution can affect the combustion process, and by extension the fuel efficiency and emissions levels. Modern multi-hole GDI nozzles generally feature a relatively complex step-hole geometry in which each hole might require knowledge of at least nine dimensions to accurately model. Due to the importance of the injection process on the output metrics of a GDI engine, a subset of internal combustion engine research has been dedicated to investigating the effects of nozzle geometry on the corresponding fuel spray distribution. X-ray spray tomography measurements of three six-hole GDI nozzles with varying hole patterns explored the effects of geometric asymmetries on the spray structure [1]. The authors found that the emitted fuel spray distribution varied between jet-like, hollow-coned, or crescent-shap...

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mentioning

confidence: 99%

A study on the relationship between internal nozzle geometry and injected mass distribution of eight ECN Spray G nozzles.

Matusik¹,

Duke²,

Sovis³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

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“…ensemble-average density fields for long (2.5ms) injections [75]. The three tomography planes are shown in Fig.…”

mentioning

confidence: 99%

“…Measurements were performed at the 7-BM beamline of the APS at Argonne [61] under the non-evaporative conditions listed in Table 1. The principles of x-ray radiography and the experimental facility at Argonne are discussed at length in previous publications [44,45,71]. In brief, a monochromatic x-ray beam of mean energy 8 keV is focused to a 5µm × 6 µm ( full width at half maximum) spot using a pair of x-ray focusing mirrors.…”

mentioning

confidence: 99%

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Duke

Kastengren

Matusik

et al. 2017

Experimental Thermal and Fluid Science

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Gasoline direct injection (GDI) sprays are complex multiphase flows. When compared to multi-hole diesel sprays, the plumes are closely spaced, and the sprays are more likely to interact. The effects of multi-jet interaction on entrainment and spray targeting can be influenced by small variations in the mass fluxes from the holes, which in turn depend on transients in the needle movement and small-scale details of the internal geometry. In this paper, we present a comprehensive overview of a multi-institutional effort to experimentally characterize the internal geometry and near-nozzle flow of the Engine Combustion Network (ECN) Spray G gasoline injector. In order to develop a complete picture of the near-nozzle flow, a standardized setup was shared between facilities. A wide range of techniques were employed, including both x-ray and visible-light diagnostics. The novel aspects of this work include both new experimental measurements, and a comparison of the results across different techniques and facilities. The breadth and depth of the data reveal phenomena which were not apparent from analysis of the individual data sets. We show that plume-to-plume variations in the mass fluxes from the holes can cause large-scale asymmetries in the entrainment field and spray structure.Both internal flow transients and small-scale geometric features can have an effect on the external flow. The sharp turning angle of the flow into the holes also causes an inward vectoring of the plumes relative to the hole drill angle, which increases with time due to entrainment of gas into a low-pressure region between the plumes. These factors increase the likelihood of spray collapse with longer injection durations.

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“…Tomography is a widely used imaging technique at synchrotron light sources (Gü rsoy et al, 2015a,b;Mohan et al, 2015;Qi & Leahy, 2006;Duke et al, 2015;Chen et al, 2012;Pelt et al, 2016). Iterative tomographic reconstruction typically provides higher-quality images than the filtered-back projection method does, because of the better reduction in noise and in missing wedge artifacts.…”

Section: Related Workmentioning

confidence: 99%

“…One of the widely desired compute-intensive applications at synchrotron light sources is iterative tomographic image reconstruction (Duke et al, 2015;Gü rsoy et al, 2015a,b). This application enables scientists to observe the internal structure of objects from 3D images.…”

Section: Introductionmentioning

confidence: 99%

Optimization of tomographic reconstruction workflows on geographically distributed resources

Biçer

Gürsoy

Kettimuthu

et al. 2016

J Synchrotron Radiat

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New technological advancements in synchrotron light sources enable data acquisitions at unprecedented levels. This emergent trend affects not only the size of the generated data but also the need for larger computational resources. Although beamline scientists and users have access to local computational resources, these are typically limited and can result in extended execution times. Applications that are based on iterative processing as in tomographic reconstruction methods require high-performance compute clusters for timely analysis of data. Here, time-sensitive analysis and processing of Advanced Photon Source data on geographically distributed resources are focused on. Two main challenges are considered: (i) modeling of the performance of tomographic reconstruction workflows and (ii) transparent execution of these workflows on distributed resources. For the former, three main stages are considered: (i) data transfer between storage and computational resources, (i) wait/queue time of reconstruction jobs at compute resources, and (iii) computation of reconstruction tasks. These performance models allow evaluation and estimation of the execution time of any given iterative tomographic reconstruction workflow that runs on geographically distributed resources. For the latter challenge, a workflow management system is built, which can automate the execution of workflows and minimize the user interaction with the underlying infrastructure. The system utilizes Globus to perform secure and efficient data transfer operations. The proposed models and the workflow management system are evaluated by using three high-performance computing and two storage resources, all of which are geographically distributed. Workflows were created with different computational requirements using two compute-intensive tomographic reconstruction algorithms. Experimental evaluation shows that the proposed models and system can be used for selecting the optimum resources, which in turn can provide up to 3.13Â speedup (on experimented resources). Moreover, the error rates of the models range between 2.1 and 23.3% (considering workflow execution times), where the accuracy of the model estimations increases with higher computational demands in reconstruction tasks.

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Time-resolved X-ray Tomography of Gasoline Direct Injection Sprays

Cited by 38 publications

References 27 publications

A study on the relationship between internal nozzle geometry and injected mass distribution of eight ECN Spray G nozzles.

A study on the relationship between internal nozzle geometry and injected mass distribution of eight ECN Spray G nozzles.

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Optimization of tomographic reconstruction workflows on geographically distributed resources

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