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NATURAL CONVECTION IN A SQUARE ENCLOSURE WITH DIFFERENT OPENINGS AND INVOLVES TWO CYLINDERS: A NUMERICAL APPROACH

Mahmud H. Ali, Rawand E. Jalal
Frontiers in Heat and Mass Transfer (FHMT) 15 - 27 (2020)


Abstract


In this work, natural convection in an adiabatic enclosure with openings induced by two isothermal hot cylinders is approached numerically. The study covers five different configurations of the enclosure as the number and locations of the inlet and outlet ports are varied for Rayleigh number (Ra) between 104 and 106. Additionally, the study also analyzes the effects of varying the horizontal distance (S) between the cylinders along with their vertical locations (d) for dimensionless values of 0.4 to 0.3 and -0.2 to 0.2, respectively, at a constant Ra of 106. The outcomes show that the locations of the openings have a significant influence on the amount of the heat being transferred. When both d and S are kept unchanged, and at low Ra, where conduction is the main reason for heat transfer, configurations with two facing inlets illustrate low heat transfer up to Ra = 2.5x105 which is reversed as Ra increases. However, for changes in S at Ra = 106, when the heat is mainly being dissipated by convection, these configurations are not only dissipating more heat rates but also show low sensitivity to increase in S. Low sensitivity for changes in d has also been observed for the configuration with two facing outlets and one inlet. In overall, in all considered configurations, the average Nusselt number varies inversely with variation in d. Similar change is observed for configurations that have one inlet as well with variation in S. The configuration with symmetrically distributed ports shows distinguished results in heat dissipation characteristics.


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DOI: http://dx.doi.org/10.5098/hmt.15.27

ISSN: 2151-8629