Numerical investigation of ZnO–MWCNTs/ethylene glycol hybrid nanofluid flow with activation energy

MHD second-grade nanofluid slip flow over a stretching sheet subject to activation energy, thermophoresis, and Brownian effects

“…Viscous dissipation and elastic deformation effects are incorporated in the temperature equation. Following [22,24,25,37], the activation energy is analyzed. The present nanofluid flow geometry is illustrated in figure 1.…”

“…The results show an increase in entropy generation with higher values of Reynolds and Brinkman numbers. Prashar and Ojjela [25] have considered activation energy and Joulian dissipation influence on second-grade ZnO − MWCNT/EG hybrid nanofluid flow. The investigation of bioconvection and activation energy impact on mixed convective flow of Carreau fluid past a stretching sheet was performed by Rehman et al [26].…”

Impact of needle size and distinct flow conditions on thermal performance of TiO2–MWCNTs hybrid nanofluid flow past thin needle using Casson fluid model

“…After this, the effective density $${\rho _{hnf}}$$, viscosity $${\mu _{hnf}}$$, and heat capacity $${(\rho {C_p})_{hnf}}$$ [27, 38, 49, 50] of the TiO 2 –MWCNTs/EG–water hybrid nanofluid are computed similarly by the Equations ()–(). $$$$\begin{equation}{\mu _{hnf}} = \frac{1}{{{{\left( {1 - {\phi _1}} \right)}^{2.5}}{{\left( {1 - {\phi _2}} \right)}^{2.5}}}}{\mu _f},\end{equation}$$$$ $$$$\begin{equation}{\rho _{hnf}} = \left\{ {\left( {1 - {\phi _2}} \right)\left( {\left( {1 - {\phi _1}} \right) + {\phi _1}\frac{{{\rho _s}}}{{{\rho _f}}}} \right) + {\phi _2}\frac{{{\rho _{\rm CNT}}}}{{{\rho _f}}}} \right\}{\rho _f},\,\,\,\end{equation}$$$$ …”

“…After this, the system of equations given in Equation () subject to the initial conditions () is integrated by the Runge–Kutta method till $${\eta _\infty }$$. The numerical results obtained by integration at $${\eta _\infty }$$ are compared to the actual values given by the boundary conditions at $${\eta _\infty }$$ which is done by the Newton‐Raphson method [27, 38, 53, 54]. The MATLAB code developed for the numerical solution is validated against the results published by Soid et al.…”

“…To attain a better understanding of the heat exchange phenomenon in boundary layers and to use that information for practical design purposes, it is much needed to take the help of simulations and numerical investigations. The heat exchange involved in the boundary layer flow past the thin needle, stretching/shrinking sheet, or disk using different mathematical or computational methods has been studied widely, some of which are mentioned here [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. A lot of hybrid nanofluids comprising MWCNTs and metal oxide nanoparticles as their constituents exhibit non-Newtonian nature, as discussed in the last paragraph.…”