Natural convective heat transfer in water enclosed between pairs of differentially heated vertical plates

Abstract

This paper presents the results of an experimental study of buoyancy-driven convective heat transfer between three parallel vertical plates, symmetrically spaced with water as the intervening medium. The centre plate was electrically heated, while the other side plates were water-cooled forming two successive parallel vertical channels of dimensions 20 cm × 3.5 cm × 35 cm (length W, gap L, height H) each. Top, bottom and sides of the channels were open to water in the chamber which is the novel aspect of this study. Plate surface temperature and bath temperature at different levels of height from the bottom of channel were measured by K-type thermocouples. Experimental data have been correlated as under: $$ \begin{gathered} Nu = 0.62\,Gr^{{0.29}} ,\quad 1.17\,{\text{E}}6 \le Gr \le 1.48\,{\text{E}}7,\quad 2.9 \le Pr \le 4.7,\quad A = 10.3 \hfill \\ Nu = 0.14\,Ra^{{0.35}} ,\quad 5.25\,{\text{E}}6 \le Ra \le 4.36\,{\text{E7,}}\quad 2. 9\le Pr \le 4. 7 ,\quad A = 10.3. \hfill \\ \end{gathered} $$