Influence of Induced Magnetic Field on Free Convection of Nanofluid Considering Koo-Kleinstreuer-Li (KKL) Correlation
Influence of Induced Magnetic Field on Free Convection of Nanofluid Considering...
Sheikholeslami, M.;Zia, Q. M. Zaigham;Ellahi, R.
2016-11-02 00:00:00
applied sciences Article Influence of Induced Magnetic Field on Free Convection of Nanofluid Considering Koo-Kleinstreuer-Li (KKL) Correlation 1 2 3 , 4 , M. Sheikholeslami , Q. M. Zaigham Zia and R. Ellahi * Department of Mechanical Engineering, Babol University of Technology, Babol 484, Iran; mohsen.sheikholeslami@yahoo.com Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 45550, Pakistan; zaighum_zia@comsats.edu.pk Department of Mathematics & Statistics, FBAS, IIUI, H-10 Sector, Islamabad 44000, Pakistan Mathematics Faculty of Science Taibah University, Madinah 41411, Munawwarah, Saudi Arabia * Correspondence: rellahi@engr.ucr.edu or rahmatellahi@yahoo.com Academic Editor: Fan-Gang Tseng Received: 3 September 2016; Accepted: 24 October 2016; Published: 2 November 2016 Abstract: In this paper, the influence of induced magnetic field on free convection of Al O -water 2 3 nanofluid on permeable plate by means of Koo-Kleinstreuer-Li (KKL) model is reported. Impact of Brownian motion, along with the properties of nanofluid, are also taken into account. The resulting equations are solved utilizing Runge-Kutta integration method. Obtained results are examined for innumerable energetic parameters, namely Al O volume fraction, suction parameter, and Hartmann 2 3 and magnetic Prandtl numbers. Results indicate that the velocity profile reduces with rise of the suction parameter and magnetic Prandtl and Hartmann numbers but it increases with addition of nanoparticles. Shear stress enhances with rise of suction parameter, magnetic Prandtl and Hartmann numbers. Temperature gradient improves with augment of suction parameter. Keywords: induced magnetic field; nanofluid; free convection; permeable plate; current density 1. Introduction Magnetohydrodynamic (MHD) free convection has several applications, such as combustion modeling, geophysics, fire engineering, etc. In recent decades, nanotechnology has been presented as a new passive technique for heat transfer improvement. MHD nanofluid natural convection in a tilted wavy cavity has been presented by Sheremet et al. [1]. They illustrated that a change of titled angle causes convective heat transfer to be enhanced. 3D MHD free convective heat transfer was examined by Sheikholeslami and Ellahi [2] using Lattice Boltzmann method (LBM). Their results showed that Lorentz forces cause the temperature gradient to reduce. Ismael et al. [3] investigated the influence of Lorentz forces on nanofluid flow in an enclosure with moving walls. Their outputs indicated that the impact of Lorentz forces reduces with direction of magnetic field. Sheikholeslami and Ellahi [4] utilized LBM to study Fe O -water flow, with the aim of drug delivery. They concluded that the 3 4 velocity gradient reduces with the rise of magnetic number. The influence of non-uniform Lorentz forces on nanofluid flow style has been studied by Sheikholeslami Kandelousi [5]. He concluded that improvement in heat transfer reduces with rise of Kelvin forces. A new model for nanofluid on peristaltic flow was presented by Tripathi and Beg [6]. They reported different behavior for nanofluid temperature profiles with changing temperature. Kouloulias et al. [7] presented an experimental analysis for free convection of nanofluid. They showed that greater nanoparticle volume fraction leads to higher Rayleigh numbers. Appl. Sci. 2016, 6, 324; doi:10.3390/app6110324 www.mdpi.com/journal/applsci Appl. Sci. 2016, 6, 324 2 of 13 The influence of thermal radiation on magnetohydrodynamic nanofluid motion has been reported by Sheikholeslami et al. [8]. They concluded that the nanofluid concentration gradient augments with the rise of the radiation parameter. Mineral oil-based nanofluids have been utilized in natural convection by Peña et al. [9]. MHD Fe O -water flow in a wavy cavity with moving wall has been 3 4 investigated by Sheikholeslami and Chamkha [10]. The influence of Lorentz forces on forced convective heat transfer has been examined by Sheikholeslami et al. [11]. They illustrated that a greater Reynolds number has a more sensible effect on Kelvin forces. Akbar and Khan [12] investigated the impact of magnetic field on nanofluid motion in an asymmetric channel. Hakeem et al. [13] studied the influence of Lorentz forces on various nanofluids by means of second order slip flow mode. They showed that a unique solution exists for this problem for high Hartman number values. Several researchers have investigated about this subject [14–22]. In almost all the previous papers, the authors neglected the induced magnetic field. However, in various physical states it is necessary to consider this effect in governing equations. This assumption is considered in order to simplify the mathematical analysis of the problem. Furthermore, the induced magnetic field produces its own magnetic field in the fluid; therefore, it can amend the original magnetic field. Also, nanofluid motion in the magnetic field produces mechanical forces which change the motion of motion. Ghosh et al. [23] reported the impact of induced Lorentz forces on temperature profile. Unsteady magnetohydrodynamic flow on a cone has been investigated by Vanita and Kumar [24]. Beg et al. [25] examined the impact of induced magnetic field on boundary layer flow. The influence of atherosclerosis on hemodynamics of stenosis has been forecasted by Nadeem and Ijaz [26]. They showed that the velocity gradient on the wall of titled arteries reduces with augment of Strommers number. The chief end of this paper is to illustrate the influence of induced magnetic field on nanofluid hydrothermal treatment between two vertical plates. To obtain outputs, Runge-Kutta method is selected. The impacts of the suction parameter, magnetic Prandtl and Hartmann numbers, volume fraction of nanofluid on temperature, and induced magnetic, velocity and current density profiles are examined. 2. Problem Statement Al O -water fluid through two vertical permeable sheets is investigated as illustrated in Figure 1. 2 3 The boundary conditions are clear in this figure. The variables are only the function of y because plates are infinite. Velocity and magnetic field vectors are considered as v = [u, v , 0] and b = [b , b , 0] 0 0 respectively. The governing equations and boundary conditions can be obtained as follows: d u b db du e 0 x + + g (T T ) + v = 0 (1) n f n f 0 0 dy dy dy n f 1 d b du db x x + b + v = 0 (2) 0 0 dy dy dy e n f d T dT n f + v = 0 (3) dy dy n f dT q b 0 = 0, u 0 = 0, 0 = (4) ( ) ( ) ( ) dy k db (h) = 0, u (h) = 0, T (h) = T (5) dy Appl. Sci. 2016, 6, 324 3 of 13 () , C , ( ) and can be introduced as [3]: n f n f n f n f 3 / 1 ( p ) n f f = 1 + , ( ) = (1 ) ( ) + ( ) , n f f p ( / +2) ( / 1) p f p f (6) ( C ) = ( C ) + ( C ) (1 ), = + (1 ) p p p n f p f n f p f k and are obtained according to Koo-Kleinstreuer-Li (KKL) model [27]: n f n f 3 k /k 1 ( ) p f T 4 0 k = + 1 + 5 10 c g (d , T, ) n f p, f f k /k 1 + k /k +2 p p ( p ) ( p ) f f g d , T, = (7) a + a Ln d + a Ln d + a Ln () + a ln d Ln () Ln (T) + p p p 1 2 5 3 4 a + a Ln d + a Ln d + a Ln () + a ln d Ln () 6 7 p p 8 9 p 8 2 R = d 1/k 1/k , R = 4 10 km /W p p f p,e f f f f k f Brownian = + (8) n f 2.5 k Pr (1 ) f All needed coefficients and properties are illustrated in Tables 1 and 2 [27]. Dimensionless parameters are presented as: e 2 1 U = , B = b g h DT , = DT (T T ) , DT = qh/k , Y = 2 f x f 0 f g h DT f q (9) f B h v h 0 e 0 Pr = C , Pm = , Ha = , V = p 0 e f f f k f f f Finally, the dimensionless governing equations are d U Ha dB A A A dU 1 6 1 + + + V = 0 (10) A dY A A dY dY 2 2 2 d B dB dU + A V Pm + A HaPm = 0 (11) 5 0 5 dY dY dY d A d + V Pr = 0 (12) dY A dY B (0) = 0, U (0) = 0, (0) = 1 (13) dY dB (1) = 0, U (1) = 0, (1) = 0 (14) dY Induced current density can be defined: J = dB/dY (15) C and Nu can be expressed as: C = U (0), Nu = A /(0). (16) f 4 1 Appl. Sci. 2016, 6, 324 4 of 13 Appl. Sci. 2016, 6, 324 4 of 13 Figure 1. Geometry of the problem. Figure 1. Geometry of the problem. Table 1. Constants of Al O Water [27]. Table1. Constants of Al O2 3Water [27]. Al O Water Coefficient Coef Va ficient lues Values Al O Water 2 3 a a 552.813 2.813 a 6.115 a 2 6.115 a 0.695 0.695