ITEMS

modern scholarly publishers in the finest tradition

Journals

	Search

Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2003, Volume13

211 pages

DOI: 10.1615/AtomizSpr.v13.i56

Issue price - $150.00

ENTRAINMENT CONTROL FOR LIGAMENT-CONTROLLED EFFERVESCENT ATOMIZER SPRAYS

T. J. Kuta
Maurice J. Zucrow Laboratories (formerly Thermal Sciences and Propulsion Center), School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA

Michael W. Plesniak
Maurice J. Zucrow Laboratories (formerly Thermal Sciences and Propulsion Center), School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA

Paul E. Sojka
Maurice J. Zucrow Laboratories (formerly Thermal Sciences and Propulsion Center), School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA

ABSTRACT

Ligament-controlled effervescent atomization (LCEA) was developed as a means of reducing effervescent atomizer air-to-liquid ratios by mass (ALR) from 2% to as low as 0.75%. This reduction in ALR offers an obvious advantage in numerous applications (e.g., combustion systems because of reduced parasitic losses or paint/coating sprays because of improved penetration into corners). Reduction of ALR is a necessity for consumer product sprays because of the limited quantity of atomizing air available in a prepressurized package.
This study focused on passive control of entrainment by ligament-controlled effervescent atomizer sprays. Spray control was investigated by considering the entrainment-modifying effects of four exitorifice geometries having a common diameter of 0.38 mm but different indeterminate-origins—four-point crown, two-point crown, inclined, and stepped. Each geometry was tested at two liquid mass flow rates (0.5 and 0.6 g/s), four air-to-liquid ratios (0.75 ≤ ALR ≤ 2.0%), and four axial distances (67 ≤ x/d₀ ≤ 417). Data were acquired for a single bulk liquid—water. Both the atomizing gas and the entrainment gas were dried, high-pressure air.
Steady entrainment rate and momentum rate data were used to calculate entrainment numbers, E, for sprays produced using each of the entrainment-modifying geometries. Results of this experimental investigation are summarized as follows: (1) Normalized entrainment rates (m_e/m_l) were found to scale linearly with normalized axial distance (x/d₀) and to increase with increasing ALR for all exitorifice geometries. (2) Entrainment numbers were found to increase with increasing ALR for all exitorifice geometries. (3) The four-point and two-point crowns were found to enhance entrainment by the sprays, whereas the inclined and stepped exits were found to suppress it.