The effect of the number of tube rows on heat, mass and momentum transfer in flat-plate finned tube heat exchangers

The effect of the number of tube rows on heat, mass and momentum transfer i s experimentally investigated for flat-plate, finned-tube heat exchangers w hich consist of aluminum. fins and copper tubes. Four flat-plate finned-tub e heat exchangers are identical except for changes in the number of tube ro ws (1 to 4). Heat-transfer coefficients for wet and dry surface conditions are obtained for both heating and cooling of moist air flowing over finned tubes. The air velocity was varied from 0.9 to 4 m/s. Heat transfer, Colbur n and friction factors are determinated for different tube rows numbers whi le the Reynolds number were being warried. It is found that the values of C olburn and friction factors for wet surfaces are higher than for dry surfac es and for both conditions the Colburn and friction factors decrease with a n increase in the tube row numbers. (C) 2001 Elsevier Science Ltd. All righ ts reserved.