Multidiffusive nanofluid flow over a sphere with time-reliant nonlinear convective regime: Impact of activation energy

Abstract

The problem is modeled using correlations representing a binary chemical reaction, activation energy with multiple diffusions, and a nanofluid. The fundamental objective of this study is to characterize the time, activation energy, and diffusions of liquid hydrogen and ammonia in a nonlinear mixed convective flow around a sphere. First, the nonsimilar transformations are applied to convert the dimensional governing equations to dimensionless form. The obtained equations are then discretized using the implicit finite difference method after being linearized using the quasilinearization method. By increasing the temperature difference ratio and the Brownian diffusion parameter and decreasing the combined convection, Brinkman number, and thermophoresis, it is possible to reduce the entropy generation. The activation energies improve while chemical reaction parameters reduce the width of liquid hydrogen and ammonia’s concentration boundary layer. The results reveal that the mass transport strength of liquid ammonia is big enough to dwarf liquid hydrogen. The mass transport strength of liquid ammonia $R{e}^{-1/2}S{h}_2$ is greater than that of the liquid hydrogen’s mass transport strength $R{e}^{-1/2}S{h}_1.$ Specifically, at $\tau =1,$ the $R{e}^{-1/2}S{h}_2$ is 25% greater than the $R{e}^{-1/2}S{h}_1$ at $\mathit{\text{Nt}}=0.5$ when $\alpha >0.$ Further, at $\tau =1,$ the nanoparticle’s mass transportation strength enhances approximately 28% if Lewis number Le rises from 10 to 20 at $\mathit{\text{Nr}}=1$ for $\alpha >0.$

Keywords:

• Activation energy
• entropy generation
• nanofluid
• quasilinearization technique
• triple diffusion
• unsteady flow

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

The second author is thankful for financial support to the Department of Science and Technology-Innovation in Science Pursuit for Inspired Research (DST-INSPIRE), New Delhi with grant No. DST/INSPIRE Fellowship/2019/IF190225.