Heat transfer performance of cross-fin-tube-type heat exchangers with vortex generators

摘要

We have studied the influence of winglet-stamping hole positions, inclined β angles (winglet face angle to fin surface) and winglets array to cross-fin-tube type fins on heat transfer performance. Heat transfer performance was measured for proto-type heat exchangers with rectangular-type vortex generators by a transient heat transfer measuring method. Results indicate that the backward-stamping winglets (stamping holes positioned downstream to winglets) were 19% higher than forward-stamping winglets ( stamping holes positioned upstream to winglets) during the heat transfer ; The optimal winglet-inclined angle of β =60° which maxmizes the ratio [j{sub}H ]/[friction factor f] and j{sub}H was achieved The winglet array positioned upstream to the pipes was superior to the winglet array positioned downstream to the pipes during both the hear transfer and the pressure drop These data suggest that the corner vortices by using winglets inclined to an upsrtream position [1] is an effective enhancement method during heat transfer.