Natural Convection Heat and Mass Transfer . By Y. J ALURIA . Pergamon, 1980. 326 pp. $57.00.  Numerical Heat Transfer and Fluid Flow.  By S. V. P ATANKAR . Hemisphere-McGraw-Hill, 1980. 197 pp. $22.50 or £13.60.

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.

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The Experimental Investigation of Steam Condensation With Non-Condensable Gas Under Natural Convection

Volume 6A: Thermal-Hydraulics and Safety Analyses ◽

10.1115/icone26-81292 ◽

2018 ◽

Author(s):

Xizhen Ma ◽

Wen Fu ◽

Haijun Jia ◽

Peiyue Li ◽

Jun Li

Keyword(s):

Heat Transfer ◽

Mass Transfer ◽

High Pressure ◽

Natural Convection ◽

Heat And Mass Transfer ◽

Vertical Wall ◽

Experimental System ◽

Steam Condensation ◽

Transfer Coefficients ◽

Calculation Results

The non-condensable gas is used to keep the pressure stable in the steam-gas pressurizer. The processes of heat and mass transfer during steam condensation in the presence of non-condensable gas play an important role and the thermal hydraulic characteristics in the pressurizer is particularly complicated due to the non-condensable gas. The effects of non-condensable gas on the process of heat and mass transfer during steam condensation were experimental investigated. A steam condensation experimental system under high pressure and natural convection was built and nitrogen was chosen in the experiments. The steam and nitrogen were considered in thermal equilibrium and shared the same temperature in the vessel under natural convection. In the experiments, the factors, for instance, pressure, mass fraction of nitrogen, subcooling of wall and the distribution of nitrogen in the steam, had been taken into account. The rate of heat transfer of steam condensation on the vertical wall with nitrogen was obtained and the heat transfer coefficients were also calculated. The characteristics curve of heat and mass transfer during steam condensation with non-condensable gas under high pressure were obtained and an empirical correlation was introduced to calculated to heat transfer coefficient of steam condensation with nitrogen which the calculation results showed great agreement with the experimental data.

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