Session: 06-01: Spray Modeling

Paper Number: 140571

140571 - Improving Lagrangian Spray Modeling in the Near-Nozzle Region 

Abstract: 

The near-nozzle region of the injected fuel spray continues to present challenges to traditional Lagrangian-Eulerian (LE) modeling efforts, as the region is typically completely unresolved. Notably, it has been found that LE models do not represent the physics of the radial dispersion that occurs over the length of the near-field. The present work proposes a new Near-Field Lagrangian Dispersion Model (NFLDM) which maintains the liquid Lagrangian parcel format of traditional LE models while improving the physical representation within the near-field. Based on a Langevin analysis, the model references self-similar reconstructions of mean velocity and Reynolds stress fields obtained from experimentally validated Volume of Fluid (VoF) simulations, as well as a representation of the autocovariance function for simulation time-step independence. A measured quasi-steady behavior of the flow-field within the near-nozzle region justifies the usage of mean statistics in the transient NFLDM. The model, including the self-similarity and autocovariance functions, is generalized for various injection conditions. Validation of the model is via comparison with Projected Mass Density (PMD) data from the baseline VoF calculations using the ECN’s Spray-A and Spray-D geometries under 2-4.5 MPa ambient gas conditions and over a range of high-pressure liquid injections, including n-dodecane and methanol. In the scope of larger-scale simulations, the near-field model is coupled with a transition to a traditional LE treatment farther downstream.

Presenting Author: Michael Mason University of Wisconsin-Madison

Presenting Author Biography: Michael Mason is a Ph.D. candidate in mechanical engineering under advisor Dr. Mario Trujillo at the University of Wisconsin-Madison and is a member of the Engine Research Center (ERC). He previously obtained his MS from the same program. His research is in computational fluid dynamics focused on spray atomization.

Authors:

Michael Mason University of Wisconsin-Madison
Mario Trujillo University of Wisconsin-Madison