LOCAL CONVECTIVE BEHAVIOR AND FIN EFFICIENCY IN SHALLOW BANKS OF IN-LINE AND STAGGERED, ANNULARLY FINNED TUBES

Local mass transfer data for high-profile fins in the second row of in -line and staggered, circular-finned tubes are presented for Reynolds numbers from 5000 to 28,000 based on hydraulic diameter and velocity a t the minimum flow area. The data, obtained using an optical adaptatio n of the naphthalene sublimation technique, show that local variations in heat transfer do not cause significant fin efficiency deviations f rom the analytical solution of Gardner (contrary to earlier reports). Average heat transfer and pressure drop data indicate that the thermal performance of the in-line arrangement is comparable to the staggered configuration.