Library Subscription: Guest
Home Begell Digital Library eBooks Journals References & Proceedings Research Collections
Atomization and Sprays

Impact factor: 0.928

ISSN Print: 1044-5110
ISSN Online: 1936-2684

You have access to:
Volume 24, 2014 Volume 23, 2013 Volume 22, 2012 Volume 21, 2011 Volume 20, 2010 Volume 19, 2009 Volume 18, 2008 Volume 17, 2007 Volume 16, 2006 Volume 15, 2005 Volume 14, 2004 Volume 13, 2003 Volume 12, 2002 Volume 11, 2001 Volume 10, 2000 Volume 9, 1999 Volume 8, 1998 Volume 7, 1997 Volume 6, 1996 Volume 5, 1995 Volume 4, 1994 Volume 3, 1993 Volume 2, 1992 Volume 1, 1991

Atomization and Sprays

DOI: 10.1615/AtomizSpr.v20.i2.50
pages 163-175

EFFECT OF AMBIENT TEMPERATURE AND DENSITY ON SHOCK WAVE GENERATION IN A DIESEL ENGINE

Sanghoon Kook
Sydney School of Mechanical and Manufacturing Engineering, The University of New South Wales, NSW 2052, Australia
Lyle M. Pickett
Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, USA

ABSTRACT

Shock-wave generation by high-pressure diesel sprays has been investigated over a range of ambient temperature and density in a high-temperature, high-pressure optical vessel. In the past, shock wave generation was considered unlikely for diesel sprays because of the high-temperature environment and low fuel injection pressure. However, recent trends toward very high injection pressures, and earlier (lower temperature) injection in modern diesel engines, can potentially produce shock waves. Through high-speed schlieren imaging, injection-resolved shock waves have been captured at injection pressures of 150 MPa. Marked changes in shock wave generation are shown to occur with variation in ambient conditions that are experienced in an engine, including the following: (1) Shock waves diminish in strength with increasing temperature and eventually disappear due to the increasing speed of sound. (2) At low ambient temperature, high-density ambient gas quickly decelerates the tip of the spray, causing shock waves to detach from the spray. (3) At high ambient temperature, the high density decelerates the spray tip during injection-rate ramp-up before the spray reaches the speed of sound, such that no shock waves are produced.