HEAT-TRANSFER IN RECTANGULAR CHANNELS WITH A SERIES OF NORMALLY IN-LINE POSITIONED PLATES

Periodically fully developed flow and heat transfer were numerically s tudied for a rectangular channel with normally in-line positioned plat es along the axis. The governing equations were solved using a finite volume technique. Consideration was given only to laminar flow with un iform heat flux heating conditions at the channel walls. The independe nt governing parameters were identified as flow Reynolds number (Re), Prandtl number (Pr), pitch ratio of the plates (L / H), channel blocka ge ratio (B / H), plate thickness to height ratio (t / B), and the rat io of the thermal conductivity of the plate to the fluid (K). Calculat ions were made for the following range of independent parameters: Re l ess-than-or-equal-to 500, 0.7 less-than-or-equal-to Pr less-than-or-eq ual-to 12, 0.5 less-than-or-equal-to L / H less-than-or-equal-to 5.0, 0.2 less-than-or-equal-to B / H less-than-or-equal-to 0.8, 0.1 less-th an-or-equal-to t / B less-than-or-equal-to 0.3, and 8 less-than-or-equ al-to K less-than-or-equal-to 80,000. Heat transfer at the channel wal ls increased with a decrease in L / H; however, for L / H > 5.0, the i mpact of L / H on heat transfer was found to be minimal. Heat transfer increased with an increase in B / H, but the increase in pressure dro p was prohibitively high for B / H greater-than-or-equal-to 0.6. The t hermal conductivity ratio (K) was found to have no impact on heat tran sfer at the channel walls. Correlations were established for heat tran sfer ratio (N) and friction factor ratio (F*), along the channel wall s, as a function of Re with the above independent governing parameters .