Investigation of ice disturbance characteristics of mobile aeration device based on solid-fluid-thermal coupling
Long-distance water conveyance projects are essential in solving northern China's water resource shortage problem.However,the complex water transport conditions caused by river icing in winter seriously affect the channel's water transport capacity and the project's safe operation.Balancing the safety issues with water delivery efficiency has become a significant challenge for engineering water delivery operations.Increasing the surface water temperature to delay ice formation is possible by utilizing a mobile aeration device and this ensures the safety of winter operations and enhances the water conveyance capacity of the long-distance water conveyance project.However,as an active measure to increase the winter water delivery capacity of channel engineering,its working adaptability and disturbance heating effect still lack targeted research.To reflect the changes in water characteristics under aeration operation,computational fluid dynamics numerical simulation could be used as a reliable means of fluid research.The solid-fluid-thermal coupling technology is used to simulate the rotation of spiral blades and aeration.Simultaneously considering the heat exchange between water and atmosphere,the changes in water temperature caused by changes in the flow field are calculated.During the simulation,overlapping grid technology is introduced to optimize the dynamic grid calculation,ensuring computational efficiency and accuracy.The initial velocity distribution,temperature distribution,device operating speed,and operating path of the fluid through user-defined functions are set.Two different calculation schemes are designed to simulate and analyze the water characteristics under different aeration speeds,aeration depths,longitudinal distances,and walking speeds.The average temperature change curve and the average water surface temperature distribution map are drawn.The changes in water characteristics under different device parameters are changed and flow operating conditions are pushed,providing a basis for device parameters and operational design.The results are as follows:(1)Increasing the aeration rate within the safe allowable range can enhance the mixing effect of water.The aeration rate characterizes the size of the aeration amount.A higher aeration rate results in more significant disturbance to the water body and a higher increase in water surface temperature.(2)The aeration depth can increase the upper limit of temperature increase.A higher deep-water temperature can cause a greater temperature to increase as well.The disturbance caused by deeper aeration has a greater resistance to water pressure.In the case of insufficient aeration,the disturbance caused by deep aeration will gradually flatten with the upward migration of water flow.Considering the influence of slope,a depth of 1.5 m is recommended as the appropriate device parameter.(3)The optimal walking distance for operation is 2 m.Expanding the distance can increase the range of disturbed water surface,and secondary mixing will be carried out in local areas to increase water surface temperature.However,excessive longitudinal distance can lead to the appearance of low-temperature fault zones,which is not conducive to improving the efficiency of turbulent flow heating.(4)The trend of the effect of walking speed on temperature increases first weakens and then strengthens.When the speed is less than 2 m/s,the slower walking speed results in higher local aeration and a more substantial temperature mixing effect.After the speed exceeds 2 m/s,the acceleration of the speed causes the device to undergo secondary disturbance on the walking path.The improvement of the warming effect is more significant than the weakening effect caused by the reduction of local aeration.
water transfer in freezing periodaerationwater temperature mixingsolid-fluid-thermal coupling
万方数据
维普
