抄録
A new concept of the enhancement of forced-convection heat transfer effective in the range of Reynolds numbers lower than 3 000 is presented. The new surface has many small holes and is bent to form a trapezoid. The phase of each adjacent surface is changed by half a period, and therefore a heat exchanger constructed with these perforated surfaces alternately has enlargement and contraction sections along the flow passages. The performance of the new heat exchanger employing this enhancement technique is studied experimentally. It is shown that the mechanism of the heat-transfer enhancement is mainly due to the secondary flow induced by the suction and injection through the perforations. The heat-transfer coefficient of the new heat exchanger increases by about three times that of a parallel-plate heat exchanger at the same Reynolds number.
