Доступ предоставлен для: Guest
Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
Atomization and Sprays
Импакт фактор: 1.262 5-летний Импакт фактор: 1.518 SJR: 0.814 SNIP: 1.18 CiteScore™: 1.6

ISSN Печать: 1044-5110
ISSN Онлайн: 1936-2684

Выпуски:
Том 29, 2019 Том 28, 2018 Том 27, 2017 Том 26, 2016 Том 25, 2015 Том 24, 2014 Том 23, 2013 Том 22, 2012 Том 21, 2011 Том 20, 2010 Том 19, 2009 Том 18, 2008 Том 17, 2007 Том 16, 2006 Том 15, 2005 Том 14, 2004 Том 13, 2003 Том 12, 2002 Том 11, 2001 Том 10, 2000 Том 9, 1999 Том 8, 1998 Том 7, 1997 Том 6, 1996 Том 5, 1995 Том 4, 1994 Том 3, 1993 Том 2, 1992 Том 1, 1991

Atomization and Sprays

DOI: 10.1615/AtomizSpr.2016014272
pages 1241-1257

EFFECT OF THE PROPELLANT MASS FRACTION IN A BINARY MIXTURE ON THE SPRAY CHARACTERISTICS AS GENERATED BY HOMOGENEOUS FLASH BOILING

Moti Levy
Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa, Israel
Yeshayahou Levy
Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa, Israel
Eran Sher
Ben-Gurion University of Negev, Israel

Краткое описание

When a binary mixture of a high vapor pressure propellant and a low vapor pressure component is injected through a simple atomizer at high enough pressure, flash boiling of the propellant may occur. Due to the sudden depressurization, propellant-vapor nuclei are developed to a rapid evaporation, resulting in break-up of the liquid mixture into a fine spray that is characterized by tiny and fairly uniform droplets. This method is presently used in quite a number of applications. Depending on the initial conditions we distinguish between heterogeneous and homogeneous nucleation. Flash-boiling process within the aperture leads to highly efficient atomization. Finer sprays are achieved when increasing the superheating degree; thus, homogeneous nucleation is apparently the preferred regime for atomization. Nevertheless, experimental studies involving atomization under homogeneous nucleation regime are rather scarce. In the present work we study the effect of the propellant mass fraction in a binary mixture on the spray characteristics as generated by a homogeneous flash-boiling process. We have selected Chlorodifluoromethane (CHClF2 or R-22), and PMX-200 silicon oil as the two components of the mixture and studied the effect of the mixing ratio on the droplets' velocity and size distribution and the radial distribution of the droplets' velocity and size. We used a TSI's Phase Doppler Particle Analyzer (PDPA) to characterize the spray, and a controlled 3D positioning system to measure the droplets characteristics at accurate and specific positions. We show that lowering the mass fraction of the propellant results in a progressively higher value of the mean velocity at any radial distance, a higher mean droplets' size, and a higher standard deviation. For the present homogeneous nucleation flash-boiling atomization system, we found that the break-up efficiency, as defined by Sher and Zeigerson-Katz [Atomization Sprays, vol. 6, no. 4 (1996)], is rather low, on the order of 10−6, while a higher propellant mass fraction yields a lower process efficiency. The lower efficiency is attributed to the different mechanisms of spray formation in homogeneous and heterogeneous nucleation.


Articles with similar content:

INFLUENCE OF FUEL PROPERTIES ON THE DIESEL INJECTION PROCESS IN NONVAPORIZING CONDITIONS
Atomization and Sprays, Vol.22, 2012, issue 6
Christine Mounaim-Rousselle, S. Houille, Hespel Camille, Fabrice Foucher, J. Dernotte
EFFECT OF ATOMIZING AIR FLOW ON SPRAY ATOMIZATION OF AN INTERNAL-MIX TWIN-FLUID ATOMIZER
Atomization and Sprays, Vol.25, 2015, issue 8
Cheng Tung Chong, Simone Hochgreb
EXPERIMENTAL INVESTIGATION OF SPRAY CHARACTERISTICS OF DIESEL-METHANOL-WATER EMULSION
Atomization and Sprays, Vol.25, 2015, issue 8
Wuqiang Wang, Shenteng Cao, Dongyin Wu, Junjie Yan, Zhenzhou Pang
EFFECT OF INJECTION STRATEGY ON THE SPRAY DEVELOPMENT PROCESS IN A SINGLE-CYLINDER OPTICAL GDI ENGINE
Atomization and Sprays, Vol.25, 2015, issue 9
Sungwook Park, Jingeun Song
CHARACTERISTICS OF TRANSIENT, SWIRL-GENERATED, HOLLOW-CONE SPRAYS
Atomization and Sprays, Vol.16, 2006, issue 5
Julian T. Kashdan, John S. Shrimpton