OPEN ACCESS
Understanding the disturbances introduced by cavitation inside spray nozzles is important, when simulating the spray formation of highly viscous liquids. In this paper, a new model for cavitation-induced primary break-up is proposed, which is able to map the influence of cavitating nozzle flow on spray formation. Detailed experimental and numerical investigations of the viscous nozzle flow have been performed in order to develop an improved primary break-up model [1]. The proposed model describes the transition from the flow inside the nozzle, modelled using a homogeneous equilibrium model (HEM) method, to the first primary droplets modelled using a Eulerian–Lagrangian method. Thus, providing the boundary conditions for the calculation of the secondary break-up and spray formation. The nozzle exit is divided into a definite number of patches. Liquid momentum and vapor volume frac- tion from each patch are used to initialize the primary droplets. The model has been implemented in the open-source CFD software package OpenFOAM and validation has been done using high-speed shadow graphic imaging. The simulated spray tip penetration and spray cone angle at the near-nozzle region show a good agreement with the experiment results.
cavitation, numerical simulation, OpenFOAM, primary break-up, Spray formation, viscous liquids
[1] Ravendran, R., deClaville Christiansen, J., Jensen, P. & Endelt, B., Numerical study of cavitation of high-viscous liquid spray systems. ILASS Americas 28th Annual Conference on Liquid Atomization and Spray Systems, pp. 1–12, May 2016.
[2] Fansler, T.D. & Parrish, S.E., Spray measurement technology: a review. Measurement Science and Technology, 26(1), p. 012002, 2015.
[3] Le Moyne, L., Trends in atomization theory. International Journal of Spray and Combustion Dynamics, 2(1), pp. 49–84, 2010.
[4] Sou, A., Hosokawa, S. & Tomiyama, A., Effects of cavitation in a nozzle on liquid jet atomization. International Journal of Heat and Mass Transfer, 50(17–18), pp. 3575– 3582, 2007.
[5] Dabiri, S., Sirignano, W.A. & Joseph, D.D., Cavitation in an orifice flow. Physics of Fluids, 19(7), p. 072112, 2007.
[6] Dumouchel, C., On the experimental investigation on primary atomization of liquid streams. Experiments in Fluids, 45(3), pp. 371–422, 2008.
[7] Tamaki, N. & Shimizu, M., Enhancement of atomization of high-viscous liquid jet by pressure atomized nozzle. ILASS-Europe 2002, 2002.
[8] Franc, J.-P. & Michel, J.-M., Fundamentals of Cavitation, Springer Science + Business Media, Inc., 2006.
[9] Baumgarten, C., Stegemann, J. & Merker, G., A new model for cavitation induced primary break-up of diesel sprays. ILASS-Europe 2002, 2002.
[10] Bergwerk, W., Flow pattern in diesel nozzle spray hole. Proceedings of the Institution of Mechanical Engineers, 173(1), pp. 655–660, June 1959.
[11] Dumouchel, C., Leboucher, N. & Lisiecki, D., Cavitation and primary atomization in real injectors at low injection pressure condition. Experiments in Fluids, 54(6), pp. 1–17, 2013.
[12] Jollet, S., Hansen, H., Bitner, K., Niemeyer, D. & Dinkelacker, F., Experimental and numerical investigations of 90 micrometer real-size transparent nozzles with high pressure conditions. ILASS-Europe 2014, 2014.
[13] Pratama, R.H., Sou, A., Wada, Y. & Yokohata, H., Cavitation in mini-sac nozzle and injected liquid jet. ICLASS-2015, 2015.
[14] Andriotis, A., Gavaises, M. & Arcoumanis, C., Vortex flow and cavitation in diesel injector nozzles. Journal of Fluid Mechanics, 610, pp. 195–215, 2008.
[15] Baumgarten, C., Mixture Formation in Internal Combustion Engine, Springer Berlin Heidelberg, 2006.
[16] Mohan, B., Yang, W. & Chou, S., Cavitation in injector nozzle holes – A parametric study. Engineering Applications of Computational Fluid Mechanics, 8(1), pp. 70–81, January 2014.
[17] Yu, H., Goldsworthy, L., Brandner, P. & Garaniya, V., Modelling of in-nozzle cavitation and early spray breakup using a multiphase volume of fluid method. In 20th Australasian Fluid Mechanics Conference Perth, 2016.
[18] Mohan, B., Yang, W. & Chou, S.K., Development of an accurate cavitation coupled spray model for diesel engine simulation. Energy Conversion and Management, 77, pp. 269–277, 2014.
[19] Santos, F.D. & Moyne, L.L., Spray atomization models in engine applications, from correlations to direct numerical simulations. Oil & Gas Science and Technology–Revue d’IFP Energies Nouvelles, 66(5), pp. 801–822, 2011.
[20] Herrmann, M. On simulating primary atomization using the refined level set grid method. Atomization and Sprays, 21(4), pp. 283–301, 2011.
[21] Arcoumanis, C., Gavaises, M. & French, B., Effect of fuel injection processes on the structure of diesel sprays. SAE Technical Paper 970799, 1997.
[22] Nishimura, A. & Assanis, D.N., A model for primary diesel fuel atomization based on cavitation bubble collapse energy. ICLASS 2000, pp. 1249–1256, 2000.
[23] Ravendran, R., Endelt, B., deClaville Christiansen, J. & Jensen, P., Model for cavitation induced primary break-up of viscous liquid sprays. In Computational & Experimental Methods in Multiphase and Complex Flow, 2017.
[24] Reitz, R.D. & Beale, J.C., Modeling spray atomization with the Kelvin-Helmholtz/ Rayleigh-Taylor Hybrid model. Atomization and Sprays, 9(6), pp. 623–650, 1999.
[25] Ravendran, R., deClaville Christiansen, J., Endelt, B., Jensen, E.A. & Jensen, P., Rheological behavior of lubrication oils used in two-stroke marine engines. Industrial Lubrication and Tribology, 69(5), pp. 750–753, 2017.
[26] Assael, M.J., Dalaouti, N.K. & Vesovic, V., Viscosity of natural-gas mixtures: Measurements and prediction. International Journal of Thermophysics, 22(1), pp. 61–71, 2001.