Aerospace Science and Technology 49 (2016) 135–143 Contents lists available at ScienceDirect Aerospace Science and Technology www.elsevier.com/locate/aescte Soret and Dufour effects on flow in converging and diverging channels with chemical reaction Umar Khan ∗ , Naveed Ahmed, Syed Tauseef Mohyud-Din Department of Mathematics, Faculty of Sciences, HITEC University, Taxila Cantt, Pakistan a r t i c l e i n f o a b s t r a c t Article history: Received 16 July 2015 Received in revised form 7 October 2015 Accepted 5 December 2015 Available online 9 December 2015 Keywords: Soret and Dufour effects Converging and diverging channels Heat transfer and mass transfer ADM Nusselt number Sherwood number Heat and mass transfer analysis for the flow of viscous incompressible fluid in converging and diverging channel with chemical reaction is presented. Soret and Dufour effects are considered to analyze the thermal-diffusion and diffusion-thermo effects. Influences of first order chemical reaction are also studied. Problem is formulated for velocity, temperature and concentration fields using similarity transforms. Adomian’s Decomposition Method (ADM) is used to obtain analytical solutions. Convergence of the solution is assured. A numerical solution is also presented for the sake of comparison. Comprehensive graphical analysis is carried out to study the effects of different emerging parameters coupled with comprehensive discussions. Numerical effects of local Nusselt number and local Sherwood numbers are also discussed. Also, it is observed that temperature of the fluid increases with an increase in the angle opening for the diverging channel case while temperature decreases for converging channel.  2015 Elsevier Masson SAS. All rights reserved. 1. Introduction Flow between inclined walls is known as Jeffery–Hamel flow. Jeffery and Hamel [1,2] firstly investigated the flow between non- parallel walls and after their initiating work number of efforts have been made to understand these types of flows in a better way. This noticeable attention is due to its wide range of applications that include aerospace, chemical, civil, environmental, mechanical, bio- mechanical engineering. Rivers and channels are also drastically simplified models described by this work. By changing the angle between the walls, flow characteristics vary and different proper- ties for the flow were discussed [3,4]. Heat and mass transfer is an important area of research nowa- days due to its applications in many branches of science and tech- nology. For converging and diverging channels, recently, Mohyud- Din et al. [5] presented heat transfer analysis. In other geometries, many researchers have analyzed heat transfer involved in the flow of a viscous fluid that can be seen in literature. Simultaneous heat and mass transfer with chemical reaction plays an important role in designing of chemical processing equip- ment, formulation and dispersion of fog, damage of crops due to frost, etc. Heat transfer occurs when a liquid is heated or cooled down while mass transfer represents the escape of vapors in atmo- sphere like in boilers and cooling towers. In industries both play a * Corresponding author. E-mail address: umar_jadoon4@yahoo.com (U. Khan). vital role and hence better understanding of these phenomena is essential. It is a well-known fact that the temperature and concentration gradients present mass and energy fluxes, respectively. Concen- tration gradients result in Dufour effect (diffusion-thermo) while Soret effect (thermal-diffusion) is due to temperature gradients. For the flows of mixture of gases with light molecular weights (He, H 2 ) and moderate weights ( N 2 , air), Soret and Dufour ef- fects cannot be neglected. These on heat and mass transfer are discussed in different ways as presented in [6–9] and references therein. Also, chemical reaction plays an important role as it may affect the mass transfer of diffusing species and has been pre- sented for different geometries. It is revealed from literature survey that no attempt has been made to study the Soret and Dufour effects in converging and di- verging channels. The purpose of this article is to investigate the diffusion-thermo and thermal-diffusion effects on converging and diverging channel in the presence of a first order chemical re- action. Due to nonlinearity of the equations for these problems exact solutions are unlikely; so, many analytical techniques have been developed [10–20]. One of these techniques Adomian’s De- composition Method (ADM) [21–23] is used to solve the system of equations. ADM is a strong analytical technique that does not require any linearization or discretization or existence of small or large parameter and has been applied by many researchers to solve different nonlinear problems. Convergence of series solution is also ensured. Effects of involved physical parameters on temper- http://dx.doi.org/10.1016/j.ast.2015.12.009 1270-9638/ 2015 Elsevier Masson SAS. All rights reserved.