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Vortex flow and cavitation in diesel injector nozzles

Published online by Cambridge University Press:  08 August 2008

A. ANDRIOTIS ,
M. GAVAISES  and
C. ARCOUMANIS
A. ANDRIOTIS
Affiliation:
Research Centre for Energy and the Environment, School of Engineering and Mathematical Sciences, City University, London, Northampton Square, EC1V 0HB London, UK
M. GAVAISES*
Affiliation:
Research Centre for Energy and the Environment, School of Engineering and Mathematical Sciences, City University, London, Northampton Square, EC1V 0HB London, UK
C. ARCOUMANIS
Affiliation:
Research Centre for Energy and the Environment, School of Engineering and Mathematical Sciences, City University, London, Northampton Square, EC1V 0HB London, UK
*
†Author to whom correspondence should be addressed: m.gavaises@city.ac.uk
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Abstract

Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as ‘string-cavitation’. Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection events, implying significant hole-to-hole and cycle-to-cycle variations during the corresponding spray development.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 610 , 10 September 2008 , pp. 195 - 215
Copyright
Copyright © Cambridge University Press 2008

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References

REFERENCES

Afzal, H., Arcoumanis, C., Gavaises, M. & Kampanis, N. 1999 Internal flow in diesel injector nozzles: modelling and experiments. IMechE Paper S492/S2/99.Google Scholar
Alajbegovic, A., Grogger, H. A. & Philipp, H. 1999 Calculation of transient cavitation in nozzle using the two-fluid model. Proc. 12th Annu. Conf. on Liquid Atomization and Spray Systems. Indianapolis, Indiana, USA.Google Scholar
Andriotis, A. & Gavaises, M. 2009 Influence of vortex flow and cavitation on near-nozzle diesel spray dispersion angle. Atomiz. Sprays 19, 1–24.Google Scholar
Andriotis, A., Spathopoulou, M. & Gavaises, M. 2007 Effect of nozzle flow and cavitation structures on spray development in Low-speed two-stroke diesel engines. Proc. CIMAC 2007, Vienna, May 2007.Google Scholar
Arcoumanis, C. & Gavaises, M. 1998 Cavitation in diesel injectors: modelling and experiments. Proc. ILASS-EUROPE. Manchester, UK.Google Scholar
Arcoumanis, C., Flora, H., Gavaises, M., Kampanis, N. & Horrocks, R. 1999 Investigation of cavitation in a vertical multi-hole injector. SAE Trans. J. Engines 1999-01-0524, 108-3.CrossRefGoogle Scholar
Arcoumanis, C., Badami, M., Flora, H. & Gavaises, M. 2000 Cavitation in real-size multi-hole diesel injector nozzles. SAE Trans. J. Engines 2000-01-1249 109-3.CrossRefGoogle Scholar
Avva, R. K., Singhal, A. & Gibson, D. H. 1995. An enthalpy based model of cavitation. Cavitation and Multiphase Flow Forum, ASME FED, pp. 63–70.Google Scholar
Badock, C., Wirth, R., Fath, A. & Leipertz, A. 1999 Investigation of cavitation in real size diesel injection nozzles. Intl J. Heat Fluid Flow 20, 538–544.CrossRefGoogle Scholar
Blessing, M., König, G., Krüger, C., Michels, U. & Schwarz, V. 2003 Analysis of flow and cavitation phenomena in diesel injection nozzles and its effect on spray and mixture formation. SAE Paper 2003-01-1358.CrossRefGoogle Scholar
Chahine, G. L. & Duraiswami, R. 1992 Dynamical interactions in a multi-bubble cloud. Trans ASME J. Fluids Engng 114, 680–686.CrossRefGoogle Scholar
Chahine, G. L. & Kalumuck, K. M. 2002 Simulation of surface piercing body coupled response to underwater bubble dynamics utilizing 3DYNAFS, a three-dimensional BEM Code. Proc. IABEM 2002 – International Association for Boundary Element Methods. Austin, Texas, USA.CrossRefGoogle Scholar
Chaves, H. & Obermeier, F. 1998 Correlation between light absorption signals of cavitating nozzle flow within and outside of the hole of a transparent diesel injection nozzle. Proc. ILASS-EUROPE. Manchester, UK.Google Scholar
Chaves, H., Knapp, M., Kubitzek, A. & Obermeier, F. 1995. Experimental study of cavitation in the nozzle hole of diesel injectors using transparent nozzles. SAE Paper 950290.CrossRefGoogle Scholar
Farrell, K. J. 2003. Eulerian/Lagrangian analysis for the prediction of cavitation inception. Trans. ASME J. Fluids Engng 125, 46–52.CrossRefGoogle Scholar
Gavaises, M. & Andriotis, A. 2006 Cavitation inside multi-hole injectors for large diesel engines and its effect on the near-nozzle spray structure. SAE Trans. J. Engines 2006-01-1114 115-3, 634–647.Google Scholar
Gavaises, M., Papoulias, D., Andriotis, A., Giannadakis, E. & Theodorakakos, A. 2007 Link between cavitation development and erosion damage in diesel fuel injector nozzles. SAE Paper 2007-01-0246.CrossRefGoogle Scholar
Giannadakis, E. 2005. Modelling of cavitation in automotive fuel injector nozzles. PhD thesis, Imperial College, University of London.Google Scholar
Giannadakis, E., Papoulias, D., Gavaises, M., Arcoumanis, C., Soteriou, C. & Tang, W. 2007 Evaluation of the predictive capability of diesel nozzle cavitation models. SAE Paper 2007-01-0245CrossRefGoogle Scholar
Gopalan, S. & Katz, J. 2000 Flow structure and modeling issues in the closure region of attached cavitation. Phys. Fluids 12, 895–911.CrossRefGoogle Scholar
Gopalan, S., Katz, J. & Knio, O. 1999 The flow structure in the near field of jets and its effect on cavitation inception. J. Fluid Mech. 98, 1–43.CrossRefGoogle Scholar
He, L. & Ruiz, F. 1995 Effect of cavitation on flow and turbulence in plain orifices for high-speed atomization. Atomiz. Sprays 5, 569–584.CrossRefGoogle Scholar
Jeong, J. & Hussain, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 69–94.CrossRefGoogle Scholar
Kim, J. H., Nishida, K. & Hiroyasu, H. 1997 Characteristics of internal flow in a diesel injection nozzle. Proc. ICLASS. Seoul, Korea.CrossRefGoogle Scholar
Kubota, A., Kato, H. & Yamaguchi, H. 1992 A new modelling of cavitating flows–a numerical study of unsteady cavitation on a hydrofoil section. J. Fluid Mech. 240, 59–96.CrossRefGoogle Scholar
Laín, S., Bröder, D., Sommerfeld, M. & Göz, M. F. 2002 Modelling hydrodynamics and turbulence in a bubble column using the Euler–Lagrange procedure. Intl J. Multiphase Flow 28, 1381–1407.CrossRefGoogle Scholar
Marcer, R., Le Cottier, P., Chaves, H., Argueyrolles, B., Habchi, C. & Barbeau, B. 2000 A validated numerical simulation of diesel injector flow using a VOF method. SAE Paper 2000-01-2932.CrossRefGoogle Scholar
Martínez-Bazán, C., Montañès, J. L. & Lasheras, J. C. 1999 On the breakup of an air bubble injected into a fully developed turbulent flow. Part 2. Size PDF of the resulting daughter bubbles. J. Fluid Mech. 401, 183–207.CrossRefGoogle Scholar
Meyer, R. S., Billet, M. L. & Holl, J. W. 1992 Freestream nuclei and traveling-bubble cavitation. J. Fluids Engng. Trans ASME 114, 672–679.CrossRefGoogle Scholar
Nouri, J. M., Mitroglou, N., You You, Yan & Arcoumanis, C. 2007 Internal flow and cavitation in a multi-hole injector for gasoline direct-injection engines. SAE Paper 2007-01-1405.CrossRefGoogle Scholar
Papadakis, G. & Bergeles, G. 1995 A locally modified 2nd-order upwind scheme for convection terms discretization. Intl J. Numer. Meth. Heat Fluid Flow 5, 49–62.CrossRefGoogle Scholar
Patankar, S. V. & Spalding, B. D. 1972 A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows. Intl J. Heat Mass Transfer 15, 1787–1806.CrossRefGoogle Scholar
Plesset, M. S. & Prosperetti, A. 1977 Bubble dynamics and cavitation. Annu. Rev. Fluid Mech. 9, 145–185.CrossRefGoogle Scholar
Prosperetti, A. & Plesset, M. S. 1978. Vapour-bubble growth in a superheated liquid. J. Fluid Mech. 85, 349–368.CrossRefGoogle Scholar
Roth, H., Gavaises, M. & Arcoumanis, C. 2002 Cavitation initiation, its development and link with flow turbulence in diesel injector nozzles. SAE Trans. J. Engines, 2002-01-0214 111-3, 561–580.Google Scholar
Roth, H., Giannadakis, E., Gavaises, M., Arcoumanis, C., Omae, K., Sakata, I., Nakamura, M. & Yanagihara, H. 2005 Effect of multi-injection strategy on cavitation development in diesel injector nozzle holes. SAE Trans. J. Engines 2005-02-1237 114-3, 1029–1045.Google Scholar
Sauer, J., Winkler, G. & Schnerr, G. H. 2000 Cavitation and condensation – common aspects of physical modeling and numerical approach. Chem. Engng & Technol 23, 663–666.3.0.CO;2-H>CrossRefGoogle Scholar
Schmidt, D. P., Rutland, C. J. & Corradini, M. L. 1997 A numerical study of cavitating flow through various nozzle shapes. SAE Paper 971597.CrossRefGoogle Scholar
Shyy, W., Thakur, S., Ouyang, H., Liu, J. & Blosch, E. 1997 Computational Techniques for Complex Transport Phenomena. Cambridge University Press.CrossRefGoogle Scholar
Singhal, A. K., Athavale, M. M., Li, H. Y. & Jiang, Y. 2001 Mathematical basis and validation of the full cavitation model. Proc. FEDSM'01 – 2001 ASME Fluid Engng Division Summer Meeting. New Orleans, Louisiana, USA.Google Scholar
Singhal, A. K., Athavale, M. M., Li, H. Y. & Jiang, Y. 2002 Mathematical basis and validation of the full cavitation model. Trans ASME J. Fluids Engng 124, 617–624.CrossRefGoogle Scholar
Soteriou, C., Andrews, R. J. & Smith, M. 1995 Direct injection diesel sprays and the effect of cavitation and hydraulic flip on atomization. SAE Paper 950080.CrossRefGoogle Scholar
Soteriou, C., Andrews, R. J., Torres, N., Smith, M. & Kunkulagunta, R. 2001 Through the diesel nozzle hole – a journey of discovery. Proc. ILASS Americas, 14th Annu. Conf. on Liquid Atomization and Spray Systems. Dearborn, Michigan, USA.Google Scholar
Soteriou, C., Lambert, M., Zuelch, S. & Passerel, D. 2006. The flow characteristics of high efficiency Diesel nozzles with enhanced geometry holes. Proc. THIESEL Intl Conf. on Thermo- and Fluid Dynamic Processes in Diesel Engines. Valencia, Spain.Google Scholar
Vaidyanathan, R., Senocak, I., WU, J. Y. & Shyy, W. 2003. Sensitivity evaluation of a transport-based turbulent cavitation model. Trans ASME J. Fluids Engng 125, 447–458.CrossRefGoogle Scholar
Yakhot, V., Orszag, S. A., Thangam, S., Gatski, T. B. & Speziale, C. G. 1992. Development of turbulence models for shear flows by a double expansion technique. Phy. Fluids A 4, 1510–1520.CrossRefGoogle Scholar