Abstract
The investigation considers numerical analysis and computational solution of unsteady, pressure-driven channel flow of a generalized viscoelastic-fluid-based nanofluid (GVFBN) subject to exothermic reactions. Temperature-dependent fluid thermal conductivity is considered, and the flow is subject to convective cooling at the walls. The non-isothermal generalized Giesekus constitutive model is employed for the GVFBN. A Carreau model is used to describe the shear-rate dependence of fluid viscosity, and exothermic reactions are assumed to follow Arrhenius kinetics. An efficient semi-implicit numerical technique based on the finite-difference method is applied to obtain computational solutions to the model equations. The computational methodologies are built into the MATLAB software. The effects of various fluid and flow parameters, specifically the nanoparticle volume fraction, are explored. The results demonstrate that those parameters which only directly couple to the energy equation (but are otherwise indirectly coupled to momentum and stress-constitutive equations, say via the temperature-dependent viscosities and relaxation times) would only show prominent effects on fluid temperature but not on the fluid velocity or the polymer stresses. The results also demonstrate, as in the literature on exothermic flows, that the values of exothermic-reaction parameter must be carefully controlled as large values would lead to thermal runway phenomena. The illustrated results are consistent with the existing literature and additionally add novel new contributions to non-isothermal and pressure-driven channel flow of GVFBN under convective cooling conditions.
Highlights
A mixture of metallic nanometre-sized particles suspended in a conventional base fluid is referred to as a nanofluid
Optimal material conditions for fluid viscosity and thermal conductivity may be enhanced by simultaneously using several types of nanoparticles of various shapes, sizes, density, etc. in the same nanofluid mixture. e present research focuses on the effects of shear-dependent viscosity and fluid elasticity and will use homogeneous nanoparticles of one kind for illustrative purposes
A vast majority of the research on nanofluid flow has been conducted with Newtonian base fluids. e recent developments in non-isothermal constitutive models for viscoelastic fluid flow and their related applications have made it possible for the extension of the Newtonian-based fluid models to more general nonNewtonian-fluid-based nanofluids. e current work represents such an extension to viscoelastic nanofluidics, using generalized viscoelastic-fluid-based nanofluid (GVFBN)
Summary
E investigation considers numerical analysis and computational solution of unsteady, pressure-driven channel flow of a generalized viscoelastic-fluid-based nanofluid (GVFBN) subject to exothermic reactions. Temperature-dependent fluid thermal conductivity is considered, and the flow is subject to convective cooling at the walls. E non-isothermal generalized Giesekus constitutive model is employed for the GVFBN. E results demonstrate that those parameters which only directly couple to the energy equation (but are otherwise indirectly coupled to momentum and stress-constitutive equations, say via the temperature-dependent viscosities and relaxation times) would only show prominent effects on fluid temperature but not on the fluid velocity or the polymer stresses. E illustrated results are consistent with the existing literature and add novel new contributions to non-isothermal and pressure-driven channel flow of GVFBN under convective cooling conditions An efficient semi-implicit numerical technique based on the finite-difference method is applied to obtain computational solutions to the model equations. e computational methodologies are built into the MATLAB software. e effects of various fluid and flow parameters, the nanoparticle volume fraction, are explored. e results demonstrate that those parameters which only directly couple to the energy equation (but are otherwise indirectly coupled to momentum and stress-constitutive equations, say via the temperature-dependent viscosities and relaxation times) would only show prominent effects on fluid temperature but not on the fluid velocity or the polymer stresses. e results demonstrate, as in the literature on exothermic flows, that the values of exothermic-reaction parameter must be carefully controlled as large values would lead to thermal runway phenomena. e illustrated results are consistent with the existing literature and add novel new contributions to non-isothermal and pressure-driven channel flow of GVFBN under convective cooling conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
