Investigation of Enhanced Heat Transfer in Low Reynolds Number Flows in a Plate Heat Exchanger

Steady-state heat transfer and pressure drop data for single-phase low Reynolds number flows (2 ≤ Re ≤ 400) in a plate heat exchanger (PHE) with chevron plates are presented. Three different chevron plate arrangements, with two symmetric (β = 30°/30° and 60°/60°) and one mixed (β = 30°/60°) plates, are considered in a single-pass, U-type, counter-flow PHE. The effects of the corrugation inclination angle β, and flow conditions on Nu and f characteristics of the PHE are investigated using vegetable oil as test fluid (130 < Pr < 290). The results indicate that as β increases, up to 3 times higher Nu are obtained in chevron plates compared to an equivalent flat-plate pack; the concomitant f, however, are up to 9 times higher. Correlations of the functional form

Nu(Re, Pr, β, d_e/L, μ/μ_w) and f(Re, β)

are developed, and they predict all available data within ±10%. Finally, the performance of chevron plates is evaluated relative to an equivalent flat-plate channel for two different operating constraints: (1) Fixed geometry and constant pumping power, and (2) fixed heat load and pressure drop.