Numerical study on magneto-convection of cold water in an open cavity with variable fluid properties

Highlights: → We investigate the magneto-convection of cold water in an open cavity. → Temperature of maximum density leaves strong effects on flow and heat transfer. → Convection is enhanced by thermocapillary force when buoyancy force is weakened. → Heat transfer behaves nonlinearly with density inversion parameter and Marangoni number. → Heat transfer rate decreases on increasing the Hartmann number. - Abstract: The aim of the present study is to understand the problem of buoyancy and thermocapillary induced convection of cold water near its density maximum in an open cavity with temperature dependent properties in the presence of uniform external magnetic field. The governing equations are solved by the finite volume method. The results are discussed for various values of reference temperature parameter, density inversion parameter, Rayleigh, Hartmann and Marangoni numbers. It is observed that the temperature of maximum density leaves strong effects on fluid flow and heat transfer due to the formation of bi-cellular structure. Convection heat transfer is enhanced by thermocapillary force when buoyancy force is weakened.