Numerical study of the turbulent natural convection of nanofluids in a partially heated cubic cavity

Abstract

In this work we study numerically the three-dimensional turbulent natural convection in a partially heated cubic cavity filled with water containing metallic nanoparticles, metallic oxides and others based on carbon.The objective is to study and compare the effect of the addition of nanoparticles studied in water and also the effect of the position of the heated partition on the heat exchange by turbulent natural convection in this type of geometry, which can significantly improve the design of heat exchange systems for better space optimization. For this we have treated numerically for different volume fractions the turbulent natural convection in the two cases where the cavity is heated respectively by a vertical and horizontal strip in the middle of one of the vertical walls. To take into account the effects of turbulence, we used the standard turbulence model ? - ?. The governing equations are discretized by the finite volume method using the power law scheme which offers a good stability characteristic in this type of flow. The results are presented in the form of isothermal lines and current lines. The variation of the mean Nusselt number is calculated for the two positions of the heated partition as a function of the volume fraction of the nanoparticles studied in water for different Rayleigh numbers.The results show that carbon-based nanoparticles intensify heat exchange by convection better and that the position of the heated partition significantly influences heat exchange by natural convection. In fact, an improvement in the average Nusselt number of more than 20% is observed for the case where the heated partition is horizontal.

Numerical investigation of turbulent mixed convection in a round bottom flask using a hybrid nanofluid

“…It represents the balance between the rate of change of momentum, the pressure forces, and the viscous forces acting on the fluid. 32…”

“…The energy equation, also known as the heat transfer equation or the first law of thermodynamics, is a fundamental equation in thermodynamics and fluid dynamics that describes the conservation of energy in a fluid flow. The energy equation can be written as 32 :…”

“…The rate of energy dissipation, also known as the dissipation rate, refers to the rate at which mechanical energy is converted into internal energy or heat within a fluid flow. 32…”

“…Turbulent kinetic energy refers to the energy associated with the chaotic and irregular motion of fluid particles in a turbulent flow. It represents the fluctuating component of kinetic energy in a turbulent flow field 32. …”

Turbulent natural-convection heat transfer in a square cavity with nanofluids in presence of inclined magnetic field

“…The results show that heat transfer improves with increasing volume fraction of nanoparticles and decreases with increasing Hartmann number. Recently, Lafdaili et al [11][12] studied the heat transfer by natural turbulent convection in a two-dimensional and three-dimensional cavity filled with water containing suspended nanoparticles. They examined the effect of the form ratio and the nanoparticle type on heat transfer and flow structure.…”