On the Distance Required to Atomize Diesel Sprays Injected from Orifice-Type Nozzles

Abstract

Conductivity probe measurements, using ranges of nozzles, liquid properties and gas densities, have revealed more extensive and reliable information on the break-up process of diesel sprays than has been published to date. The spray generated from a single-hole orifice-type nozzle has an incompletely atomized break-up length which typically extends at least 100 hole diameters downstream. The physical structure of this break-up zone varies, depending on the liquid properties and both initial and boundary conditions, from that of a central liquid column, with outer drops and ligaments, to, more typically, that of a chaotic ‘wire wool’ structure of ligaments and drops. Time variations of the break-up length are found during spray pulses and concentrations of poorly atomized liquid are convected downstream in the form of coherent structures. The existence of this zone has repercussions with respect to spray-gas flow interaction, fuel vaporization and wall wetting in internal combustion engines.

Keywords

diesel engines sprays injection fuel properties

Get full access to this article

View all access options for this article.

References

Rayleigh

Lord

On the instability of jets. Proc. London Math. Soc., 1878, 10, 4–13.

Ohnesorge

Formation of drops by nozzles and the break-up of liquid jets. Z. Angew. Math. Mech., 1936, 16, 355–358.

Reitz

R. D.

Atomization and other break-up regimes of a liquid jet. PhD thesis, Princeton University, 1978.

Taylor

J. J.

Hoyt

J. W.

Water jet photography—techniques and methods. Exp. Fluids, 1983, 1, 113–120.

Gulder

O. L.

Smallwood

G. J.

Snelling

D. R.

Diesel spray structure investigation by laser diffraction and sheet illumination. SAE paper 920577, 1992, Society of Automotive Engineers, Warrendale, Pa.

Arai

Tabata

Hiroyasu

Shimizu

Disintegrating process and spray characterization of fuel jet injected by a diesel nozzle. SAE paper 840275, 1984, Society of Automotive Engineers, Warrendale, Pa.

Yule

A. J.

Filipovic

On the break-up times and lengths of diesel sprays. Int. J. Heat and Fluid Flow, 1992, 13, 197–206.

Yule

A. J.

Salters

D. G.

A conductivity probe technique for investigation of the break-up of diesel sprays. Atomization and Sprays, 1994, 4, 41–64.

Lefebvre

A. H.

Atomization and sprays, 1989 (Hemisphere Publishing Corporation, New York).

10.

Arai

Shimizu

Hiroyasu

Similarity between the break-up lengths of a high speed liquid jet in atmospheric and pressurised conditions. Proc. ICLASS-91, NIST, Gaithersburgh, Maryland, 1991, 563–570.

11.

Smallwood

G. J.

Gulder

O. L.

Snelling

D. R.

Tomographic visualization of the dense core region in transient diesel sprays. Proc. ICLASS-94, Rouen, France, 1994 (Begell House Incorporated, New York).

12.

Reitz

R. D.

Bracco

F. V.

Mechanism of atomization of a liquid jet. Phys. Fluids, 1982, 25, 1730–1742.

13.

Yule

A. J.

Watkins

A. P.

Measurement and modelling of diesel sprays. Atomization and Sprays, 1991, 1, 445–469.

14.

Chatwani

A. U.

Bracco

F. V.

Computation of dense spray jets. Proc. ICLASS-85, Institute of Energy, London, 1985, Section IB/1, 1–12.

15.

Andrews

M. J.

The large-scale fragmentation of the intact liquid core of a spray jet. Atomization and Sprays, 1993, 3, 29–54.

16.

Phinney

R. E.

Humphries

Stability of a viscous jet-Newtonian liquids. U.S. Naval Ordnance Laboratory Report 70–5, 1970 (U.S. Naval Ordnance Laboratory, White Oak, Maryland).

17.

Chehroudi

Chen

S. H.

Bracco

F. V.

On the intact core of full cone sprays. SAE paper 850126, 1985, Society of Automotive Engineers, Warrendale, Pa.

18.

Yule

A. J.

Salters

D. G.

The break-up zone of a diesel spray: Part 1, length of zone and volume of unatomized liquid. Atomization and Sprays, 1995, 5, 157–174.

19.

Zanelli

Behaviour of a liquid jet near the nozzle. Proc. ICLASS-88, Fuel Society, Sendai, Japan, 1988, 1–14.

20.

Salters

D. G.

Studies of the break-up zones of diesel sprays using an improved conductivity probe methodology. PhD thesis, Department of Mechanical Engineering, University of Manchester Institute of Science and Technology, Manchester, 1993.