Analysis Of Resistance Characteristics Of Air Conditioning Duct And Components

The resistance of air conditioning duct and component is one of the important factors that affect the efficiency of the whole ventilation system.Careful consideration is required in the design of ventilation ducts.Through using the CFD software,the pipeline resistance is simulated and the pipeline structure is optimized.And it can change the unreasonable pipeline layout,reduce the resistance loss of the ventilation system.At the same time,it can provide reference for the selection of the fan which can save the energy consumption of the fan.It is of great significance.In this thesis,the relationship between flow and resistance of the new air inlet control valve is simulated firstly,and the resistance and the resistance coefficient of the valve is calculated.Then,the test scheme and test device are designed for it.Meanwhile,the resistance of the air conditioning duct system is simulated and analyzed,and four kinds of schemes for reducing resistance are proposed,and the comparative analysis is made to determine the more reasonable scheme.Through the simulation analysis of the new air inlet control valve's resistance under different flow,the relation curve between the ventilation volume of the control valve and the control valve resistance is plotted.The numerical simulation results show that,When the air volume is within the rated range of 1~7m~3/s,the internal velocity and pressure of the control valve gradually increase with the increasing of the air volume,and the resistance of the new air inlet control valve increases accordingly.At the same time,the thesis also designs the test scheme and test device for the new air inlet control valve,which can lay a foundation for the construction of the control valve experimental device.As for the piping of air conditioning and ventilation in this thesis,because the original model is limited by space,the transition tube becomes irregular and short,which causes the problem that the resistance of inlet transition pipe is big and the speed distribution of the inlet of the cooler is not uneven.It can be seen from the comparison between the straight plate guide plate and the arc guide plate that the latter's effect of reducing resistance is better.The shape of the imported transition tube is changed to a circular arc,and the arc guide plate is arranged inside it,which the effect of reducing resistance is 28.12%higher than the original model,and the average standard deviation coefficient(C_v)of the inlet velocity of the surface cooler is reduced by 1.76.By changing the relative position of the surface cooler and the fan,and installing the arc guide plate in the transition tube,The effect of reducing resistance is 44.3%higher than the original model,and the average standard deviation coefficient(C_v)of the surface cooler's inlet velocity is reduced by 2.20.Based on the above analysis,when the installation space is limited,by changing the shape of the transition tube and changing the relative position of the ventilator and the cooler,the resistance of ventilation ducts can be reduced effectively.