Transient natural convection is numerically investigated in an enclosure using variable thermal conductivity, viscosity, and the thermal expansion coefficient of Al2O3-water nanofluid. The study has been conducted for a wide range of Rayleigh numbers (103≤ Ra ≤ 106), concentrations of nanoparticles (0% ≤ ϕ ≤ 7%), the enclosure aspect ratio (AR =1), and temperature differences between the cold a...

For thermal mixed-convection flows, the Nusselt number is a function of Reynolds number, Grashof number and the angle between the forcedand natural-convection directions. We consider flow over a heated cylinder for which there is no universal correlation that accurately predicts Nusselt number as a function of these parameters, especially in opposing-convection flows, where the natural convecti...

Transient natural convection taking place in an originally isothermal cylinder filled with a porous medium after sudden change of wall temperature is studied experimentally and computationally. A mathematical model is developed, and the parameters influencing natural convection are identified. Results from simulations are compared with experiments allowing for model validation.

Sal'nikov's chemical reaction is very simple; it consists of two consecutive first-order steps, yielding a product B from a precursor P via an active intermediate A, in P→A→B. The first of these steps is assumed here to be thermoneutral, with zero activation energy, whilst the second step is taken to be exothermic with a positive activation energy. These properties make this reaction one of the...

in this paper, the effect of the brownian term in natural convection of cuo-water nanofluid inside a partially filled porous cavity, with internal heat generation has been studied. it is assumed that the viscosity and thermal conductivity of nanofluid consists of a static part and a brownian part of which is a function of temperature and the volume fraction of nanofluid. because of internal hea...

This study discusses the application of Taguchi method in assessing minimum entropy generation and maximum heat transfer rate for natural convection in an enclosure embedded with isothermal cylinder. The simulations were planned based on Taguchi’s L25 orthogonal array with each trial performed under different conditions of position and aspect ratio (AR) of the cylinder. The thermal lattice Bolt...

The interaction of thermal radiation with conduction and laminar natural convection in a vertical circular pin, situated at participating gas, is numerically investigated. An absorbing and emitting gas is considered, and treated to be a gray participating media. Under the idealizing of gray gas, the Rosselan4 approximation is employed to describe the radiative heat flux in the energy equation. ...

The interaction of thermal radiation with conduction and laminar natural convection in a vertical circular pin, situated at participating gas, is numerically investigated. An absorbing and emitting gas is considered, and treated to be a gray participating media. Under the idealizing of gray gas, the Rosselan4 approximation is employed to describe the radiative heat flux in the energy equation. ...

T. Tsuji Y. Nagano Department of Mechanical Engineering Nagoya Institute of Technology, Nagoya, Japan l lA turbulent natural convection boundary layer along a vertical flat plate in air is investigated with hot-wire techniques. Profile measurements of mean velocity, mean temperature, and turbulent quantities, which are obtained well into the wall region, clarify some characteristics peculiar to...