Hartmann number

About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.

Heat transfer and hydromagnetic control of flow exit conditions inside oscillatory squeezed thin films

Abstract: The influence of fluids inertia and the effects of the presence of a magnetic field normal to the direction of the flow of an electrically conducting fluid are studied on flow and heat transfer inside a nonisothermal and incompressible thin film undergoing oscillatory squeezing. The governing equations have been nondimensionalized and solved numerically. Further, the influence of the squeezing Reynolds number, thermal squeezing number, Hartmann number, and the squeezing frequency are determined. It is shown that flow instabilities appear at large squeezing Reynolds numbers and that the Nusselt number is affected by inertia effects as a result of increased squeezing Reynolds number. Further, it is found that flow instabilities are reduced when the magnetic field is introduced.

Magneto‐hydrodynamic squeeze film characteristics for finite rectangular plates

Abstract: The squeeze‐film characteristics between two parallel rectangular plates with an electrically conducting fluid in the presence of a transverse magnetic field are analyzed. The squeeze‐film Reynolds equation applicable to the curved surfaces is derived using the continuity equation and the magneto‐hydrodynamic (MHD) motion equations. A closed‐form solution is obtained for the squeeze‐film pressure of parallel rectangular plates, and applied to predict the squeeze‐film behavior. According to the results, the presence of magnetic fields signifies an enhancement in the squeeze‐film pressure. On the whole, the magnetic‐field effect characterized by the Hartmann number provides an increase in value of the load‐carrying capacity and the response time as compared to the classical non‐conducting lubricant case, especially for larger values of the aspect ratio or smaller values of film height.

Mixed Convection of Hybrid Nanofluid in an Inclined Enclosure with a Circular Center Heater under Inclined Magnetic Field

Abstract: The hybrid nanofluids have efficient thermal networking due to the trade-off between the pros and cons of the more than one type of suspension. In the current study, water-based hybrid nanofluid is used to investigate mixed convection in a squared enclosure heated with a circular center heater. The cavity is placed inclined under the uniform inclined magnetic field. The squared cavity comprises of two adiabatic vertical walls and two cold horizontal walls. The governing equations are normalized using a suitable set of variables and are solved with the finite element method. A comparison is provided with previously reported results at limiting case. The grid independence is examined for the Nusselt number at the central heater. The analysis reveals the effective role of the concentration of hybrid nanofluid particles in enhancing the heat spread. The results indicate that adding 2% concentration of Ag-MgO hybrid nanoparticles causes an 18.3% uprise in the Nusselt number at the central heater. The heat transfer rate enhances for increasing Hartmann number between 0 and 10 but decreases over 10. For better heat transfer augmentation, a heater with a smaller radius is recommended for the free convection. In contrast, a heater with a larger radius serves the purpose in case of forced convection.