EXPERIMENTAL INVESTIGATION OF FLAT TUBE-LOUVER FIN HEAT EXCHANGER PERFORMANCE WORKING AS A COOLER IN DRY AND WET CONDITIONS

An experimental study has been conducted to evaluate the performance of a flat-tube louver-fin heat exchanger working as a cooler, with frontal area of 0.25 m(2) in both dry and wet conditions. Deluge water cooling at different flow rates was achieved by incorporating perforated tubetype distributor on top of the heat exchanger. Water at 35 degrees C temperature was used as heat transfer fluid at cooler inlet. Ambient air and deluge cooling water were both maintained at 22 degrees C temperature. Heat exchanger capacity and air-side pressure drop were measured with the heat exchanger angle set at 0 degrees and 210 degrees from vertical, with a frontal air velocity of 1.4 m/s and 3.5 m/s without deluge water cooling, and a frontal air velocity of 1.2 m/s, 1.4 m/s with deluge water cooling. Significant capacity enhancement could be obtained both with the use of deluge water cooling and with the heat exchanger angle set at 21 degrees from vertical. Furthermore, it was found that approximately same capacity was obtained at both 0 degrees and 21 degrees angle when wetting water flow rate was reduced from 0.17 kg/s to 0.063 kg/s, without significant reduction in air-side pressure drop. is study highlights the importance of wetting of heat transfer surfaces of compact flat tube heat exchangers and provides motivation for further research in this area.