Scholarlink

<p>This study numerically investigates magnetohydrodynamic (<i>MHD</i>) natural convection within a porous square cavity containing two symmetrically embedded hot circular cylinders. The focus is on understanding the effects of sinusoidal thermal excitation applied to the bottom wall, with the top wall maintained at a uniform cold temperature. The governing equations are solved in transient form until a steady-state solution is reached, and all results reported correspond to the converged steady state. The governing equations, which incorporate the Boussinesq approximation, account for the influence of the Rayleigh (<i>Ra</i>), Darcy (<i>Da</i>), and Hartmann (<i>Ha</i>) numbers. Findings indicate that sinusoidal heating intensifies the thermal gradients, decreases the total entropy generation, and increases the strength of convective structures, leading to an increase in heat transfer rates. Convection is enhanced by increasing&#xa0; <i>Ra</i> but suppressed by raising <i>Ha</i> as a result of magnetic damping. But this is suppressed by sinusoidal heating, especially at more spacing between cylinders. In the case of low <i>Ra</i>, thermal irreversibility is the main contribution to entropy generation and as the <i>Ra</i> increases, the other contributions of viscous, Joule (magnetic) and porous-drag become increasingly important. Its novelty is that spatially sinusoidal bottom wall heating of an <i>MHD</i> porous enclosure with internal cylinders is used as a boundary-control method, and the total entropy generation is completely decomposed (in terms of thermal and viscous and Joule and porous-drag) contributions. The results indicate that sinusoidal heating may be a good control tool to reduce entropy generation and enhance thermal efficiency in <i>MHD</i>-modulated porous systems.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Enhancement of heat transfer and reduction of entropy generation in a porous enclosure with sinusoidal heating at the lower wall under magnetohydrodynamic effects

  • 期刊论文

  • 发表日期：

    2026年7月2日

查看全文
  • Abdul Naqeeb,
  • Shams-ul-Islam,
  • Naqeeb Ullah

摘要

This study numerically investigates magnetohydrodynamic (MHD) natural convection within a porous square cavity containing two symmetrically embedded hot circular cylinders. The focus is on understanding the effects of sinusoidal thermal excitation applied to the bottom wall, with the top wall maintained at a uniform cold temperature. The governing equations are solved in transient form until a steady-state solution is reached, and all results reported correspond to the converged steady state. The governing equations, which incorporate the Boussinesq approximation, account for the influence of the Rayleigh (Ra), Darcy (Da), and Hartmann (Ha) numbers. Findings indicate that sinusoidal heating intensifies the thermal gradients, decreases the total entropy generation, and increases the strength of convective structures, leading to an increase in heat transfer rates. Convection is enhanced by increasing  Ra but suppressed by raising Ha as a result of magnetic damping. But this is suppressed by sinusoidal heating, especially at more spacing between cylinders. In the case of low Ra, thermal irreversibility is the main contribution to entropy generation and as the Ra increases, the other contributions of viscous, Joule (magnetic) and porous-drag become increasingly important. Its novelty is that spatially sinusoidal bottom wall heating of an MHD porous enclosure with internal cylinders is used as a boundary-control method, and the total entropy generation is completely decomposed (in terms of thermal and viscous and Joule and porous-drag) contributions. The results indicate that sinusoidal heating may be a good control tool to reduce entropy generation and enhance thermal efficiency in MHD-modulated porous systems.