Density of the gas mixture in the reactor gradually increases as air enters by the molecular diffusion and natural convection
of the gas mixture in the first stage of the accident.
Convective heat transfer is divided into three categories: (1) forced convection heat transfer; (2) natural convection
heat transfer; and (3) mixed convection heat transfer.
The effect of gravitational modulation on natural convection
in a porous layer was studied by Govender .
(2) Loading natural convection
heat transfer coefficient.
To be able to make the machines smaller without reducing the power, it is important to get a better cooling of the machine, preferably by using natural convection
. The convection describes the exchange of thermal energy between physical systems depending on the thermal, velocity, and pressure, by dissipating heat.
Our proposed technology is the liquid immersion technology with natural convection
, without any pumping or any fan in the bathtub for the refrigerant circulation.
The nacelle is considered air-tight, therefore the natural convection
problem within the nacelle can be treated independently from the external conditions.
These units can deliver 650 W with forced-air cooling (750 W peak) or 400 W with free-air natural convection
cooling (650 W peak) and feature less than 500 mW no-load power consumption.
Choi and Kim  compared the use of finned circular tube to a tube without fins and conveyed that the heat transfer from the tube to the PCM was influenced by the natural convection
of the melting PCM, especially in the tube system without fins.
The numerical simulation of natural convection
of various fluids in different geometries has become the most widely used approach because of its low cost and the accuracy of its predictions.
flows with heat and mass stratification are frequently encountered in nature.