Application of the Homogeneous Relaxation Model to Simulating Cavitating Flow of a Diesel Fuel

Neroorkar, Kshitij; Shields, Bradley; Grover, Ronald O.; Torres, Alejandro Plazas; Schmidt, David P.

doi:10.4271/2012-01-1269

Cited by 23 publications

(10 citation statements)

References 13 publications

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“…The solver used in the following study is the HRM (HRMFoam) for cavitating and flash-boiling flows, which is an in-house code running on the OpenFOAM toolkit. 32 A complete description of the solver is given by Neroorkar et al; 21 a brief summary of which is given here. The HRM relates the substantial derivative of the vapor mass fraction ( x ) to the nonequilibrium time scale θ …”

Section: Methodsmentioning

confidence: 99%

“…The homogeneous relaxation model (HRM) used in this study allows a variable relaxation time for both phase change rate and temperature, which depends on the local pressure and void fraction. 21…”

Section: Introductionmentioning

confidence: 99%

“…In this article, we have undertaken high-resolution, 3D LESs of cavitating flow in a canonical nozzle geometry at fixed pressure boundary conditions using the single-fluid HRM. 21 The fluid properties have been modeled using precalculated lookup tables. 24,28 Variations in cavitation behavior between a range of gasoline–ethanol blends from E0 to E85 have been investigated.…”

Section: Introductionmentioning

confidence: 99%

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High-resolution large eddy simulations of cavitating gasoline–ethanol blends

Duke

Schmidt

Neroorkar

et al. 2013

International Journal of Engine Research

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Cavitation plays an important role in the formation of sprays in fuel injection systems. With the increasing use of gasoline–ethanol blends, there is a need to understand how changes in fluid properties due to the use of these fuels can alter cavitation behavior. Gasoline–ethanol blends are azeotropic mixtures whose properties are difficult to model. We have tabulated the thermodynamic properties of gasoline–ethanol blends using a method developed for flash-boiling simulations. The properties of neat gasoline and ethanol were obtained from National Institute of Standards and Technology REFPROP data, and blends from 0% to 85% ethanol by mass have been tabulated. We have undertaken high-resolution three-dimensional numerical simulations of cavitating flow in a 500-µm-diameter submerged nozzle using the in-house HRMFoam homogeneous relaxation model constructed from the OpenFOAM toolkit. The simulations are conducted at 1 MPa inlet pressure and atmospheric outlet pressure, corresponding to a cavitation number range of 1.066–1.084 and a Reynolds number range of 15,000–40,000. For the pure gasoline case, the numerical simulations are compared with synchrotron X-ray radiography measurements. Despite significant variation in the fluid properties, the distribution of cavitation vapor in the nozzle is relatively unaffected by the gasoline–ethanol ratio. The vapor remains attached to the nozzle wall, resulting in an unstable annular two-phase jet in the outlet. Including turbulence at the conditions studied does not significantly change mixing behavior, because the thermal nonequilibrium at the vapor–liquid interfaces acts to low-pass filter the turbulent fluctuations in both the nozzle boundary layer and jet mixing layer.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-resolution large eddy simulations of cavitating gasoline–ethanol blends

Duke

Schmidt

Neroorkar

et al. 2013

International Journal of Engine Research

Self Cite

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“…This model governs the local rate of change of the dryness fraction, which tends towards its equilibrium value, as shown in Equation. (5).…”

Section: The University Of Massachusetts Amherstmentioning

confidence: 99%

Collaborative investigation of the internal flow and near-nozzle flow of an eight-hole gasoline injector (Engine Combustion Network Spray G)

Mohapatra

Schmidt

Sforozo

et al. 2020

International Journal of Engine Research

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The internal details of fuel injectors have a profound impact on the emissions from gasoline direct injection engines. However, the impact of injector design features is not currently understood, due to the difficulty in observing and modeling internal injector flows. Gasoline direct injection flows involve moving geometry, flash boiling, and high levels of turbulent two-phase mixing. In order to better simulate these injectors, five different modeling approaches have been employed to study the engine combustion network Spray G injector. These simulation results have been compared to experimental measurements obtained, among other techniques, with X-ray diagnostics, allowing the predictions to be evaluated and critiqued. The ability of the models to predict mass flow rate through the injector is confirmed, but other features of the predictions vary in their accuracy. The prediction of plume width and fuel mass distribution varies widely, with volume-of-fluid tending to overly concentrate the fuel. All the simulations, however, seem to struggle with predicting fuel dispersion and by inference, jet velocity. This shortcoming of the predictions suggests a need to improve Eulerian modeling of dense fuel jets.

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“…The solver used in this study was developed at the University of Massachusetts [18,38,27,25,26] using the foam-extend community driven extension of the OpenFOAM [47] CFD libraries. The use of these libraries provides a well-parallelized code with intrinsic polyhedral mesh support, as well as access to a wide variety of RANS and LES turbulence models and a multitude of pre and post processing utilities.…”

Section: Model Descriptionmentioning

confidence: 99%

String flash-boiling in gasoline direct injection simulations with transient needle motion

Baldwin

Grover

Parrish

et al. 2016

International Journal of Multiphase Flow

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A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle flow and near-field sprays. Simulations were conducted with a compressible Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diffuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specified by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry. Transient needle lift and wobble were based upon ensemble averaged X-ray imaging preformed at Argonne National Lab. The minimum needle lift simulated was 5 µm and dynamic mesh motion was achieved with Laplacian smoothing. The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actuate the injection. Low needle lift is shown to result in vapor generation near the injector seat. Finally, the internal injector flow is shown to be highly complex, containing many transient and interacting vortices which result in perturbations in the spray angle and fluctuations in the mass flux. This complex internal flow also results in intermittent string flash-boiling when a strong vortex is injected and the resulting swirling spray contains a thermal * Corresponding author

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Application of the Homogeneous Relaxation Model to Simulating Cavitating Flow of a Diesel Fuel

Cited by 23 publications

References 13 publications

High-resolution large eddy simulations of cavitating gasoline–ethanol blends

High-resolution large eddy simulations of cavitating gasoline–ethanol blends

Collaborative investigation of the internal flow and near-nozzle flow of an eight-hole gasoline injector (Engine Combustion Network Spray G)

String flash-boiling in gasoline direct injection simulations with transient needle motion

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