Interaction of Natural Convective Flows Induced around Multiple Heat Sources and Its Influence on Heat Transfer

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Natural Convective flow and heat transfer around a row of vertical heated plates were investigated both analytically and experimentally. Main concerns are directed to an interaction of thermal plumes arising from the plates and also to its influence on the local heat transfer from the plates. In order to analyze the flow and temperature fields around the plates, full elliptic equations for the momentum and energy transport were solved numerically for the computational domain that encloses the whole plates. The investigations were carried out for air and water at room temperature and for the arrays of 2 to 6 vertical plates. The results showed that the present elliptic analysis well predicts the plume interaction. The analytical results also showed that the flow rates induced in between a pair of vertical plates increase with the number of plates when the gaps between the plates are larger than 10mm for water and 20mm for air. Moreover, the flow rates show larger values in the central portion of the plate array than in the outside portion under the fixed numbers of the plate arrays. The local heat transfer coefficients of the plates were also measured and they were compared with the analytical results. The present analytical results coincide fairly well with the experimental data. It was also found that the overall heat transfer coefficients of the plates increase with the number of the plate under the fixed gaps of the plate. Besides, the coefficients of the plates placed in the central portion of the arrays show higher values than those placed in the outer, portion of the arrays under the fixed number of the plates. These results depict that the flow rates in between the pairs of plates depend strongly on the numbers and situations of the plates. This also causes marked differences in the heat transfer coefficients of the plates.