tIn this study, turbulent flow and heat transfer in an air to water double-pipe heat exchanger is investigatedexperimentally. The working fluids were air, flowing in the annular pipe, and water through the innercircular tube. To attain fully developed conditions, the heat exchanger was built with additional lengthsbefore and after the test section. The inner tube was made from copper. The external tube was made ofan industrial plastic which was insulated from the environment. In this manner, the outer surface of theannular channel can be considered adiabatic. The experiments are conducted in the range of flow rateof water from 120 to 200 (L/h) and in the temperature of water in upper tank range from 70 to 90◦C.Correlations for Nusselt number and friction factor are presented for according to experimental data.Results show that velocity boundary layer thickness in air side increases with increase of the temperatureof the water in the upper tank and flow rate of water on heat transfer. Nusselt number in water side isan increasing function of inlet temperature and inlet velocity of water while opposite tend is observedfor Nusselt number in air side. Inserting agitator improves the rate of heat transfer. Enhancement of heattransfer has reverse relationship with Reynolds number
کلید واژگان :AgitatorAir to water heat exchangerTurbulent flowDouble pipeHeat transfera
ارزش ریالی : 600000 ریال
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