| In view of the low efficiency and high cost of circulating water cooling in current industrial enterprises,a new type of water-cooling fan device driven by the pressure of circulating water was designed.The device uses the residual pressure in the circulating water system to squirt the circulating hot water in the form of a fine mist,making small droplets in the spray area and ensuring a fully contact with the air to exchange heat.At the same time,the reverse force of the nozzle pushes the fan to rotate,blowing out the hot air in the spray area and supplementing the cold air into the device,so as to achieve a better cooling effect of circulating water.The water-cooling fan device requires no consumption of electricity and other fillers,therefore,it is a new type of energy-saving,green and environmentally friendly device.In this thesis,a mathematical model of the operation of the water-cooling fan is established based on the principle of kinematics,and its kinematic equation is derived,which provides reference and guidance for the residual pressure distribution of the device and the design of the nozzle.In order to analyze the spray process in the cooling tower inside the water-cooling fan,the mass and heat transfer equation between the drops and air is proposed.Simultaneously,on the basis of various flow model and turbulent model,the internal fluid flow process in the water-cooling fan is simulated,so that the velocity distribution and pressure distribution of the circulating water inside the water-cooling fan are analyzed and the velocity distribution and mass flow rate at the nozzle of the water-cooling fan are further summarized,which is taken as the initial condition of the atomizing cooling effect.The calculation model of the water-cooling fan cooling tower was established,and the MRF model and the discrete item model were combined to simulate the atomized cooling process of circulating water in the cooling tower.The speed distribution and pressure distribution of circulating cooling water in the cooling tower of the water-cooling fan are shown.Using the method of fluid-structure coupling,the modal analysis of the water-cooling fan in the static working state is carried out and finally a set of comparative system research content is formed.The following research work is finished in this thesis.(1)The structure of the sprinkler pipe is optimized by designing two different structures of sprinkler both with and without watering can.The numerical simulation results shows that the sprinkler pipe without watering can obtains greater reaction force and higher flow rate under the same working conditions,but no swirl is formed in the tip of the nozzle,and it is difficult to form spray,while the water pipe with watering can ensures a swirl with a higher quality in the watering can.(2)By optimizing the structure parameters of nozzle internal diameters,numerical simulation is carried out on the fluid condition of nozzle with various internal diameters under different working conditions.The results show that the maximum outlet velocity and flow rate can be obtained when the nozzle internal diameter is 8 mm under the same working condition,which can achieve better atomization effect.(3)Numerical simulation of atomized cooling of water-cooling fan with different inlet temperatures be performed,and the temperature of circulating hot water can be cooled to near the local dry bulb temperature.The results shows that the cooling tower of water-cooling fan has excellent cooling performance and can be adapted to different cooling conditions;(4)The spray quality parameters are optimized,and the cooling effect of circulating water particles with different particle sizes is numerically simulated.The results shows that the reduction in particle size can improve the cooling performance.Under the same working conditions,the cooling effect of 2mm particle size is increased by 2.59% compared to that of the 6mm particle size,but it is prone to a greater dropout rate.To this end,a water collector can be added in order to reduce the dropout.(5)The results of modal analysis show that the water-cooling fan is prone to resonance at low-order frequency whether it is at rest or in the running state.The maximum amplitude appears at the tip of the blades and the nozzles.The resonance occurs at a lower rotating speed of the water-cooling fan,therefore,the number of startup and shutdown should be minimized in order to ensure a prolonged service life of the water-cooling fan. |
PDF Full Text Request