Flow and heat transfer of nanofluid in an asymmetric channel with expanding and contracting walls suspended by carbon nanotubes: A numerical investigation

Flow of a nanofluid comprising a base fluid (water) and carbon nanotubes (CNTs) has been considered through a rectangular channel. The channel's walls are preamble and channel is capable of dilating or squeezing in height. Both the cases of single and multi-walled carbon nanotubes (SWCNTs and MWCNTs) have been taken into account. Using viable similarity transforms, the governing equations are converted into system of nonlinear ordinary differential equations which is solved by two numerical schemes, namely, Galerkin's method (GM) and Runge–Kutta–Fehlberg (RKF) method. In comparison, the solutions are seen to be in an excellent agreement. The variations in velocity and temperature profiles due to the involved parameters are captured using graphical aid. It has been found that the nanoparticle volume fraction ϕ not only influences the velocity and temperature profiles significantly but also the rate of heat transfer at the walls. The last section presents a summary of discoveries and conclusions made.