Enhanced Heat Transfer And Strength Analysis Of Evaporative Condenser

The evaporative condenser is widely used in the field of chemical production and refrigeration. It has advantages of water-saving, energy efficiency and small footprint, and others. There are three kinds of fluid in the heat and mass transfer process of evaporative condenser, which are the refrigerant steam condensated in the heat transfer coil tubes, and air and water mutually flow outside coil tubes. The mutual flow of air, water and refrigerant is variety, therefore there are many kinds of evaporative condenser. But the heat transfer coil tubes of the evaporative condenser is indispensable and also the most important in the process. The thesis has fulfiled the following jobs:(1)The heat and mass transfer processes of evaporative condenser have been analyzed. The conclusion is that the ability of the wind to absorb steam is of great significance on the operation of evaporative condenser. The less the relative humidity of the wind, the better the absorption capacity of the water vapor is. Little change in air temperature of the circumstances, the governing factor of relative humidity is the wet bulb temperature.(2) The design algorithm of the evaporative condenser has been optimized, the evaporation temperature and the wet bulb temperature, the distribution of air and water have been discussed, then practical design has been done for instance, the parts of evaporative condenser were selected and the problems what need to pay attention to when the entire equipment installed were discussed.(3)CFD was used to simulate air distribution in evaporative condenser, the fluid flows in the mobile channel between contraction and expansion of the bend when tubes are in cross-order, the disturbance is more intense than that in line-order. The evaporation process is strengthened in cross-order. But the resistance loss in cross-order is bigger than in line-order.(4) For different span of tubes to simulate, when the horizontal span is range from 2.0d to 2.5d and in vertical is from 1.75d to 2.0d, air flow field and the aerodynamics performance are good; carring on the simulation of the air current inlet condition, finally indicat that the flow rate angle in - 20°～20°and the flow velocity in 2.5 m / s～3.5m / s could make evaporative condensers and heat flow resistance to achieve better performance status.(5) A new plate bundle type evaporative condenser has been developed, with many processes instead of the original single-board process, which improves the flow in the plate, increases the heat transfer coefficient, and raises the evaporative condensers of heat transfer. The plate box supports well plates; because the temperature in the wall of plates is higher, fill the aging deformation of packing, so the partitioned is not filled. (6) The model was established with Solidworks for the plates of the new plate bundle type evaporative condenser. And then the stress was analyzed with COSMOS. The results suggest that attention should be paid to fixed the upper plate box when condenser assembly; Stress and thermal analysis were also done to the only one plate, the result indicates that the sideline is the weakest region, the reasonable welding material and the welding process improve welded joint's quality, reduce the temperature to welded joint's stress destruction.