PURPOSE: To reduce the quantity of a fin material required without lowering fin efficiency and contrive to reduce cost, by locally varying the plate thickness of the fin in accordance with a transmitted heat flux.
CONSTITUTION: The plate thickness (t) of the aluminum made fins 2 provided on the outside periphery of a heat-transmitting pipe 1 used as a heat source, with the plate thickness at point A taken as a reference, is varied in the x-direction so that tC=tD=0.4tA, where tC is the plate thickness at point C at the upstream end where an air flow passing through the center of the pipe is varied, tD is the plate thickness at point D on the downstream side, and tE is the plate thickness at point E at the downstream end. The plate thickness is varied in the y-direction so that tB=0.1tC, where tB is the plate thickness at point B on the upstream side. By thus varying the plate thickness (t) of the fin in accordance with the magnitude of the transmitted heat flux (q), flow distribution becomes more symmetrical on the front and back sides of the pipe 1, and temperature variation on the surfaces of the fins becomes more uniform. This is the effect of increasing the plate thickness (t) on the upstream side of air flow in accordance with the fact that the transmitted heat flux (q) in the fins is larger on the upstream side.
HIRANO TOORU
KAMIMURA SHIGEHIRO
