**Anwar Saeed 1, Zahir Shah 1, Saeed Islam 1, Muhammad Jawad 1, Asad Ullah 2, Taza Gul <sup>3</sup> and Poom Kumam 4,5,6,\***


Received: 13 March 2019; Accepted: 10 April 2019; Published: 15 April 2019

**Abstract:** In this research, the three-dimensional nanofluid thin-film flow of Casson fluid over an inclined steady rotating plane is examined. A thermal radiated nanofluid thin film flow is considered with suction/injection effects. With the help of similarity variables, the partial differential equations (PDEs) are converted into a system of ordinary differential equations (ODEs). The obtained ODEs are solved by the homotopy analysis method (HAM) with the association of MATHEMATICA software. The boundary-layer over an inclined steady rotating plane is plotted and explored in detail for the velocity, temperature, and concentration profiles. Also, the surface rate of heat transfer and shear stress are described in detail. The impact of numerous embedded parameters, such as the Schmidt number, Brownian motion parameter, thermophoretic parameter, and Casson parameter (*Sc*, *Nb*, *Nt*, γ), etc., were examined on the velocity, temperature, and concentration profiles, respectively. The essential terms of the Nusselt number and Sherwood number were also examined numerically and physically for the temperature and concentration profiles. It was observed that the radiation source improves the energy transport to enhance the flow motion. The smaller values of the Prandtl number, *Pr*, augmented the thermal boundary-layer and decreased the flow field. The increasing values of the rotation parameter decreased the thermal boundary layer thickness. These outputs are examined physically and numerically and are also discussed.

**Keywords:** Casson fluid; rotating disk; condensation film; heat generation/consumption; thermal radiation; HAM

#### **1. Introduction**

Energy is a requirement of production for every industry and is used in every engineering field. Important sources of energy are gas turbines, exchange membrane, and fuel cells [1], hydraulic-fracturing [2,3], etc. Suspensions of nanoparticles in fluids show a vital enrichment of their possessions at modest nanoparticle concentrations. Numerous researchers have worked on nanofluids and studied their role in heat transfer analysis, like nuclear reactors and other transportations. Nanofluids are smart fluids, where heat transfer can be decreased or increased in the base fluids. This research work focuses on investigating the vast range of uses that involve nanofluids, emphasizing their enriched heat transfer possessions, which are governable, and the defining features that these nanofluids preserve that make them suitable for such uses. Moreover, nanofluids are a new kind of energy transference fluid that are the suspension of base fluids and nanoparticles. For cooling requirements, usual heat transfer liquids cannot be used, due to their lesser thermal conductivity. By implanting nanoparticles into normal fluids, their thermal enactment can be enriched considerably. Choi [4] is widely accepted as the first publication that introduces the concept of nanofluids. He clarifies nano liquids as a liquid containing smaller scale particles known as nanoparticles about 1 to 100 nm in measure.

Bhatti et al. [5] explored the simultaneous impacts of the varying magnetic field of Jeffrey nanofluid. They examined the impact of physical parameters over the flow field. Xiao et al. [3] examined the relative permeability of nanofibers with the capillary pressure effect using the Fractal-Monte Carlo technique. They observed the impact of the embedding parameters with applications. Ellahi et al. [6] investigated the MHD non-Newtonian nanofluid with a temperature dependent viscosity flow through a pipe. The microchannel heat sink flow exploration cooled by a Cu water nanofluid by applying the least square method and the porous media approach was observed by Hatami et al. [7]. Hatami et al. [8] explored nanofluid laminar flow between rotating disks with heat transfer. Srinivas Acharya et al. [9] investigated nanofluid mixed convection flow with ion slip and Hall effects between two concentric cylinders. Khan et al. [10] investigated boundary-layer nanofluid flow through a stretching surface. Khanafer et al. [11] described two-dimensional Buoyancy driven flow with enhanced heat transfer enclosure utilizing nanofluids. Mahanthesh et al. [12] investigated unsteady MHD three-dimensional Eyring-Powell nanofluid flow with thermal radiation through a stretching sheet. Rashidi et al. [13] explored nanofluid with entropy generation and MHD flow on a steady porous rotating disk. Rashidi et al. [14] investigated 3-D film condensation on a steady inclined rotating disk.

Gul et al. [15] studied the heat and mass transfer analysis of a liquid film over an inclined plane. They compared integer and non-integer order results under the influence of embedded parameters. Saleh et al. [16] studied carbon-nanotubes suspended nanofluid flow with convective conditions using the Laplace transform. Sheikholeslami et al. [17] examined nanofluid flow in a semi-annulus enclosure with heat transfer and MHD effects. Sheikholeslami et al. [18] investigated flow in a semi-porous channel of MHD nanofluid with an analytical investigation. Later, these investigators [19] deliberated unsteady nanofluid flow through a stretching surface. Hayat et al. [20] explored the boundary layer flow of Maxwell nanofluid. Malik et al. [21] explored MHD flow through a stretching Erying-Powell nanofluid. Nadeem et al. [22] examined the flow of Maxwell liquid with nanoparticles through a vertical stretching surface. Raju et al. [23] examined flow with free convective heat transfer through a cone of MHD nano liquid. Rokni et al. [24] explored flow with the heat transfer of nanofluids through plates. Nadeem et al. [25] investigated flow on a stretching sheet of nano non-Newtonian liquid. Shehzad et al. [26] investigated the convective boundary conditions of Jaffrey nanoliquid flow with an MHD effect. Sheiholeslami et al. [27] explored flow with a magnetic field and heat transfer of nano liquid. Mahmoodi et al. [28] examined flow for cooling applications of nanonfluid with heat transfer. Recently, Shah et al. [29–32] investigated a rotating system in the effects of hall current and thermal radiations of nanofluid flow. Further theoretical investigations were examined by Sheikholeslami using different phenomena for nanofluids, with present usages and possessions with applications of numerous methods, can be found in [33–37]. Pour and Nassab [38] examined the convectional flow of

nanofluids using the numerical technique. The influence of the physical parameters was observed in their study.

The exploration of thin film has achieved substantial presentation due to its frequent usages in the field of technology, industry, and engineering in a short interval of time. The investigation of thin liquid flow is necessary, due to its practical uses, such as cable and fibber undercoat. Several well-known uses of thin film are the fluidization of devices, elastic sheet drawing, and constant formation. Regarding their uses, it is vital that scientists develop research on the stretching sheet of liquid films. Sandeep et al. [39] studied non-Newtonian nanoliquids' thin films' fluid flow with heat transfer. Wang [40] detected an unsteady flow of thin film fluid through a stretching sheet. Usha et al. [41] investigated unsteadily finite thin liquid past a stretching sheet. Liu et al. [42] investigated thin film flow with heat transfer on a stretching surface. Aziz et al. [43] perceived the flow on a stretching sheet of a thin fluid film for the production of heat inside. Tawade et al. [44] examined fluid flow with thermal radiation and heat transmission of a thin film. Fluid film flow on a stretching sheet with heat transfer was investigated by Andersson et al. [45]. Also, investigators [46–51] examined the flow of liquid film on a stretching surface for further dissimilar cases. Hatami et al. [52] examined 3-D nanofluid flow on a steady rotating disk. A similar related study about nanofluid can be seen in [52–56]. Jawad et al. [57] examined Darcy-Forchheimer nanofluid thin film flow with Joule dissipation and Navier's partial slip of the MHD effect. Jawad et al. [58] studied 3-D single-wall carbon nanotubes rotating flow with the impact of nonlinear thermal radiation and viscous dissipation in the presence of aqueous suspensions. Other related work can be seen in [59–63].

In view of the above important discussion, the aim of the current study is to investigate liquid film flow over an inclined plane. The momentum, thermal, and concentration boundary-layers under the influence of physical constraints for heat and mass transfer analysis will be examined physically and numerically.
