Mechanistic study on spraying of blended biodiesel using phase Doppler anemometry Juthamas Kamrak a , Benjapol Kongsombut a , Gerard Grehan b , Sawitree Saengkaew b , Kyo-Seon Kim c , Tawatchai Charinpanitkul a, * a Center of Excellence in Particle Technology, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Payathai Road, Patumwan, Bangkok 10330, Thailand b LESP/UMR CNRS6614/INSA et Universite ´ de Rouen , BP 12, avenue de l’universite ´ , 76801, Saint Etienne du Rouvray, France c Department of Chemical Engineering, Faculty of Engineering, Kangwon National University, Chuncheon, Korea article info Article history: Received 17 December 2008 Received in revised form 24 May 2009 Accepted 13 June 2009 Published online 9 July 2009 Keywords: Palm oil Diesel oil Atomization Phase Doppler anemometry Droplet abstract Droplet size and dynamics of blended palm oil-based fatty acid methyl ester (FAME) and diesel oil spray were mechanistically investigated using a phase Doppler anemometry. A two-fluid atomizer was applied for dispersing viscous blends of blended biodiesel oil with designated flow rates. It was experimentally found that the atomizer could generate a spray with large droplets with Sauter mean diameters of ca. 30 mm at low air injection pressure. Such large droplets traveled with a low velocity along their trajectory after emerging from the nozzle tip. The viscosity of blended biodiesel could significantly affect the atomizing process, resulting in the controlled droplet size distribution. Blended bio- diesel with a certain fraction of palm oil-based FAME would be consistently atomized owing to its low viscosity. However, the viscosity could exert only a small effect on the droplet velocity profile with the air injection pressure higher than 0.2 MPa. ª 2009 Elsevier Ltd. All rights reserved. 1. Introduction Regarding to a continuous increase in petroleum fuel, bio- diesel derived from palm, jatropha and rapeseed as well as used cooking oils has become of increasing interest due to their abundance and renewability [1–3]. To obtain insightful understanding of biodiesel combustion, it is necessary to conduct detailed investigation of its atomization process. In general, required information would include the droplet size and velocity distributions along the plane of injection because they are necessary for effective design of a combustion chamber [4–6]. There are some comprehensive reviews of spray atomization for industrial processes which are dictated by physical properties of atomized liquid [7,8]. However, to improve the combustion performance and particulate emis- sions, many researchers are still further investigating char- acteristics of liquid fuel spray with experimental and theoretical approaches. Regarding to various different measuring techniques, such as imaging techniques or hybrid light scattering detection systems combined with a laser Doppler velocimeter (LDV), there are several drawbacks of time consuming, limitation of non-simultaneous measure- ment, and low reliability [9,10]. Meanwhile, because of less dependence on droplet properties and simplicity, phase Doppler anemometry (PDA) has been considered as a prom- ising alternative method for examining the atomizing behaviors of such mixed fuel. Therefore, this work is focusing on employing PDA for characterizing blended biodiesel * Corresponding author. Tel./fax: þ66 2 2186480. E-mail address: ctawat@chula.ac.th (T. Charinpanitkul). Available at www.sciencedirect.com http://www.elsevier.com/locate/biombioe 0961-9534/$ – see front matter ª 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.biombioe.2009.06.011 biomass and bioenergy 33 (2009) 1452–1457