Analysis Of Resistance Characteristics Of T-shaped Tee With Different Angles And Research On Optimization Of Resistance Reduction

As people's willingness to stay in existing buildings grows,the requirements for indoor living environment comfort and air quality are also improving.Air conditioning,as the main equipment for regulating the indoor temperature and humidity and air quality,is widely used in China's buildings,raising the issue of high building energy consumption,which cannot be ignored.Specifically,the fan energy consumption caused by the resistance loss of air conditioning and ventilation ducts accounts for about 15%-30% of the building energy consumption,and this statistic is continually rising one after another.A large number of local components in the air conditioning duct is the main reason for its large resistance.In the air conditioning ventilation duct,the resistance caused by local components such as elbows and tees accounts for about 50% of the total resistance of the pipe.Therefore,the purpose of reducing the total energy consumption of the building can be achieved by reducing the local resistance loss of the pipeline.As a common local component in air conditioning and ventilation ducts,the tee is one of the main components causing high resistance of ducts and high energy consumption of fans.On these grounds,this thesis intends to adopt a combination of theoretical analysis and numerical simulation to study the resistance characteristics of shunt and merge tee in air conditioning and ventilation ducts and to optimize the structure of tee with different clamping angles,so as to explore a practical optimization method for reducing resistance.The article analyzes the necessity of pipeline resistance reduction with the characteristics of China's energy structure,and applies the method of numerical simulation to investigate the causes and influencing factors of the resistance of split and combined flow tee,by combining the existing turbulence theory and the research results that scholars have achieved:(1)The vortex and secondary flow are the main causes of local resistance loss of split and combined flow tee;(2)The influence of angle,split ratio,and area ratio on the local resistance loss of split and combined flow tee is different;(3)The local resistance loss of the combined flow tee is proportional to the angle and shunt ratio,but inversely proportional to the area ratio;(4)The local resistance loss of the shunt tee is directly proportional to the angle of clamping and inversely proportional to the area ratio,and the larger the shunt ratio is,the greater the local resistance loss between the straight – main is,and the smaller the local resistance loss between the side – main is.Then,on the basis of theoretical analysis and numerical simulation conclusions,the traditional tee structure was optimized by setting different heights of "concave and convex" arcs in the merging and diverging tee,and the main conclusions and results obtained by numerical simulation and analysis are as follows:(1)The appropriate height of the arc structure can effectively reduce the resistance loss of the tee,and obtained different heights of the "concave,convex" arc corresponding to the local resistance coefficient and reduction rate.Based on this,the optimal arcs of the ventilation pipe under different included angles are determined;(2)By comparing the total pressure diagram,velocity flow line diagram and turbulent kinetic energy distribution diagram of the conventional tee and optimized tee,the reason and mechanism of the "concave and convex" arc structure that can reduce the tee resistance are deeply explored;(3)Finally,the Q criterion vortex identification method is used to obtain the vortex structure diagram of the optimized tee and the unoptimized tee to the "concave and convex" arc structure of drag reduction mechanism carries on deeper analysis,get the concave and convex arc structure can reduce the tee components resistance of reason is that it can decompose,eliminate and inhibit the generation of the vortex.This thesis studies the resistance characteristics and resistance reduction optimization techniques of different clamping angles,reducer split,and merging tees in air conditioning and ventilation ducts.The resistance characteristics of the fluid in the tee obtained in this paper can help us to better design the pipeline,improve the efficiency of pipeline transportation,and ensure the safety of the transportation process.The local component resistance reduction optimization technology is of great significance to reduce the local resistance loss of pipelines and promote the development of energy-saving buildings in China and can provide a basis for pipeline resistance reduction research.The research in this thesis will,to a certain extent,promote the research of reducing pipeline losses by optimizing the shape of local components and promote the continued development of building energy efficiency to a better aspect.