Entropy Generation Analysis in Magnetohydrodynamic Fluid Flows

Entropy generation analysis provides a rigorous framework for quantifying irreversibility in magnetohydrodynamic (MHD) fluid systems, where the interplay of fluid motion, heat transfer and electromagnetic fields gives rise to complex sources of thermodynamic loss. In MHD flows, entropy is produced through viscous dissipation, heat conduction, and Joule heating resulting from the interaction of induced currents with magnetic fields. By evaluating local and global rates of entropy production, researchers can pinpoint dominant irreversibility mechanisms and devise strategies to minimise exergy loss. This approach finds applications in cooling of high‐heat‐flux devices, liquid metal blankets for fusion reactors and electromagnetic pumping in metallurgical processes. Second‐law analysis, often expressed via dimensionless parameters such as the Bejan number, reveals optimal operating regimes where Lorentz‐force suppression of turbulence and tailored thermal boundary conditions jointly reduce entropy generation. Modern studies combine analytical similarity solutions, high‐fidelity numerical simulation and advanced heat‐flux models to deliver design guidelines that balance magnetic damping with efficient thermal management.

Research from Nature Portfolio

Recent studies have investigated the influence of non‐Fourier heat flux on entropy production in electrically conducting hybrid nanofluids. By adopting a Cattaneo–Christov heat flux model, researchers explored how combined micropolar behaviour and magnetic fields alter thermal and velocity fields, revealing that enhanced Lorentz forces can both suppress flow instability and elevate Joule dissipation. The analysis demonstrated that material parameters such as the micropolar coupling number and magnetic interaction parameter critically shape local entropy generation profiles and global irreversibility budgets. These findings offer new insights into the thermodynamic optimisation of MHD nanofluid cooling systems under rapid transient heating.

Entropy Generation Analysis in Magnetohydrodynamic Fluid Flows publication trend

The graph below shows the total number of articles in entropy generation analysis in magnetohydrodynamic fluid flows across all publications each year (not limited to Nature Index journals).

Technical terms

Entropy generation: A measure of irreversibility in a thermodynamic process, quantifying lost work potential.

Bejan number: Dimensionless ratio indicating the relative importance of heat transfer irreversibility versus fluid friction and electromagnetic losses.

Hartmann number: Dimensionless parameter representing the ratio of electromagnetic to viscous forces in an MHD flow.

Magnetohydrodynamics (MHD): The study of the dynamics of electrically conducting fluids in the presence of magnetic fields.

Joule heating: Thermal energy generated by the resistance to electric currents in a conducting fluid.

Lorentz force: The force exerted on moving charges by magnetic fields, which modifies the momentum and energy balance of the flow.

References

1. Impact of Cattaneo-Christov heat flux model on MHD hybrid nano-micropolar fluid flow and heat transfer with viscous and joule dissipation effects. Scientific Reports (2021).
2. Entropy Generation in Magnetohydrodynamic Mixed Convection Flow over an Inclined Stretching Sheet. Entropy (2016).
3. Entropy Generation Analysis in a Variable Viscosity MHD Channel Flow with Permeable Walls and Convective Heating. Mathematical Problems in Engineering (2013).