CFD modeling of a diesel evaporator used in fuel cell systems M. Atmaca a,* , _ I. Girgin b , C. Ezgi b a Department of Mechanical Engineering, Marmara University, Technology Faculty, Turkey b Department of Mechanical Engineering, Turkish Naval Academy, Istanbul, Turkey article info Article history: Received 26 November 2015 Received in revised form 22 February 2016 Accepted 23 February 2016 Available online 17 March 2016 Keywords: Diesel Nitrogen Evaporator Heat transfer CFD Modeling abstract Diesel evaporators are one of the key components of diesel fuel processing for fuel cells. Diesel evaporator is required to evaporate diesel fuel in diesel fueled fuel cell systems. In this study, diesel evaporator which is a spiral-tube heat exchanger via indirect heat sup- plied by hot nitrogen gas is modeled and the fractional distillation curve results of diesel fuel are compared to experimental data reported in literature. In this work, the ANSYS Fluent 14.0 Computational Fluid Dynamics (CFD) code is used to simulate the 3-dimen- sional, turbulent, two-phase, multi-component and reacting flow-field, developed in a diesel evaporator. Copyright © 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Introduction Fuel Cell Systems are clean energy systems. Hydrogen is an ideal fuel for fuel cells because of its high reactivity and zero emission characteristics. However, it may not be feasible to store the hydrogen in some vehicles because of the higher volume requirements, high fuel storage cost and low energy storage efficiency and security problems. Hydrogen can be produced from any hydrocarbon fuel, various biological materials and from water. Hydrocarbon fuels, such as Liquefied Petroleum Gas (LPG), gasoline and diesel, are widely being studied for hydrogen production due to the already available infrastructure of these fuels. Diesel is a common fuel source for transportation appli- cation worldwide. Diesel is one of the best hydrogen storage systems, because of its very high volumetric hydrogen density and gravimetric density. This makes diesel reforming an attractive option for hydrogen production on-board surface ships such as land based vehicles. The first stage of a compact fuel processing system is the evaporation of diesel fuel before it enters to the hydro- desulphurization unit. A significant portion of the energy required for the whole process may be consumed in this step in the case of liquid fuel with high boiling point interval. Diesel is a complex mixture of hundreds of hydrocarbon compounds like paraffins, olefins, and aromatics. There are three methods for evaporating diesel fuels. The first approach is liquid fuel atomization, in the form of a spray, is commonly used in a large variety of technical combustion applications. Second approach is Stabilized Cool Flame regime which has been proposed by Lucka and Koehne [1]. In this case, two main * Corresponding author. Tel.: þ90 2163365770, þ90 5336967561 (mobile); fax: þ90 2163378987. E-mail address: matmaca@marmara.edu.tr (M. Atmaca). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 41 (2016) 6004 e6012 http://dx.doi.org/10.1016/j.ijhydene.2016.02.122 0360-3199/Copyright © 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.