COMPUTATIONAL & EXPERIMENTAL ANALYSIS OF HEAT FLUX AND EVAPORATIVE EFFECTIVENESS OF COPPER COIL OF HEAT DISSIPATOR
The Evaporative tubular heat exchanger is widely used in refrigeration systems, power plants, chemical industries etc. it is a device in which there is a combination of water and air are used to dissipate energy from a process fluid flowing inside the copper tubes. An experimental investigation of the heat exchanger from a liquid film falling down on a horizontal tube bundle is performed along with the dry patches formed in the experiment which is carried out at atmospheric pressure. Experiment on the falling film evaporator has been conducted with varying parameter like mass flow rate of hot water, mass flow rate of cold water, with and without the velocity of air inside the test rig for an ambient pressure and humidity. Effectiveness of the evaporative cooler is evaluated for 3×8 staggered grid tube channels on the Onset conditions of falling film evaporator and also for permanent condition of falling film evaporator. In no heat flux condition the minimum wetting mass rate of cold fluid is 0.034 kg/s. The objective of this experiment is to observe variation between the heat flux and Reynolds's number of cooling water film to better understand effective heat transfer process. The temperature variations in copper tube have been analyzed using CFD (Computational Fluid Dynamics). Mass flow rate of hot and cold water with and without velocity of air at atmospheric pressure and relative humidity parameters used for experiment and simulation. Falling film evaporative heat transfer is affected by several primary factors. To obtain an optimum heat transfer rate out of a tubular heat dissipator, there should be an adequate flow of both air and water, across it. The heat transfer coefficient of tube bundles of staggered arrangement is a function of air-water cross flow arrangement where the water is allowed to shower from top and air rises from underneath. The reduction of inlet water temperature depends upon the humidity, velocity of air and tube spacing.