An analysis of homogeneous-heterogeneous chemical reactions, entropy generation, joule heating, variable thermal conductivity, Dufour effect, Cattaneo-Christov heat and mass flux, and MHD flow of the casson fluid in a rotating channel
Year: 2026
Type: article
Abstract: Rotating channel flows of yield-stress fluids subjected to a transverse magnetic field occur in rotating chemical reactors, magnetohydrodynamic (MHD) energy-conversion devices and cooling passages of rotating machinery. This study analyses the steady, laminar MHD flow of a Casson fluid with temperature-dependent plastic viscosity between two stretching parallel plates that rotate together as a rigid body, with heat and mass transfer described by the Cattaneo–Christov double-diffusion model. Variable thermal conductivity, Rosseland radiation, internal heat generation, viscous and Joule heating produced by both the axial and the swirl velocity components, the Dufour effect and isothermal cubic-autocatalytic homogeneous–heterogeneous reactions are included, and the local entropy generation rate is evaluated. A similarity transformation reduces the problem to a twelfth-order two-point boundary-value problem with twelve boundary conditions, which is solved with the bvp4c collocation solver relative tolerance 10 −8 and verified independently by Chebyshev spectral collocation agreement better than 5 × 10 −8 , by ten exact limiting solutions, and by mesh, tolerance and initial-guess tests. Random-start, deflation and continuation searches, combined with a linear temporal stability analysis, show that the reported solution branch is the physically admissible and linearly stable one; additional branches appear only beyond identified turning points Re = 1.4 for a high-temperature thermal-runaway branch and Re = 4.9 for branches with sub-ambient temperatures. An eleven-factor face-centred central-composite response-surface analysis 156 runs, R 2 > 0.996 for all responses shows that the wall skin friction is governed mainly by the Casson parameter 51% of the main-effect magnitude, the magnetic parameter 21% and the Eckert number 18%; the Nusselt number and the entropy generation are controlled by the Eckert number 52% and the Casson parameter 25–28%; and both Sherwood numbers are controlled by the heterogeneous reaction parameter 69%, the homogeneous reaction parameter 15% and the solutal relaxation parameter 14%, with β × Ec and K × K s as the dominant interactions. These findings are model predictions; their applicability to rotating MHD reactors and catalytic devices requires experimental confirmation.
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,520
OpenAlex ID: W7223444830