Study On The Resistance And Characteristics Of Tuyere Under The Condition Of Insufficient Development Flow

The purpose of the ventilation and air conditioning system is to provide a suitable environment and acceptable air quality to meet the requirements of people’s work,life and craft production process.As the end device of the air conditioning and ventilation system and the starting device of the indoor airflow movement,the tuyere is self-evident in the ventilation and air conditioning system.The air supply jet is the initial driving force for indoor airflow movement.The appropriate air distribution is to create a comfortable environment in the work area and improve air quality.Therefore,the tuyere plays a key role in achieving the air distribution effect of the ventilation and air conditioning system in the building.The air nozzle installation specifications generally require that the air velocity at the neck of the tuyere is 3-6m/s.The static pressure loss of the tuyere after installation should not be greater than 110%of the rated value,and the actual range and diffusion radius of the tuyere should not be less than 90% of the rated value.In actual engineering,due to the limitations of site conditions(such as building structure,ceiling height,and pipeline layout,etc.),the actual connection method often causes large unevenness in the air outlet outflow,which affects the range and airflow development and diffusion of the air outlet,may cause the indoor air distribution to fail to meet the design’s expected requirements.In this paper,the method of numerical simulation and full-scale experiment is adopted.The influence of the adjacent conditions of the tuyere is taken as the research object.The different connection methods commonly used in the actual project of the tuyere are used as references.The type,specifications,and connection methods of the tyuere will affect the development of jet.To study the influence of the tuyeres in the insufficient development flow state with different adjacent conditions on the direction of the jet,the degree of mixing,the shape of the cross section of the jet,and the indoor air distribution.Through research,the adjacent conditions will make the air supply of the circular diffuser uneven.At a smaller radius of curvature and connection length,the resistance of the circular diffuser increases by 29.8% compared with the fully developed state.In practice,the air supply effect of the circular diffuser is different from the expected situation.In this paper,the effects of air velocity,specifications,connecting pipe length and bend radius of curvature on the flow pattern of the circular diffuser are discussed through calculation.The range and relative deviation of the diffuser obtained the law of pressure drop of the circular diffuser under adjacent conditions,and listed a table of recommended reasonable connection methods of the circular diffuser.Adjacent conditions will cause the jet of the spherical nozzle to deviate from the jet in the fully developed state but not obvious.When the length of the connecting pipe gradually becomes longer and the radius of curvature of the connecting bend increases gradually,the deviation effect produced becomes less and less obvious.Due to the tapered structure of the spherical nozzle itself at the outlet,the insufficient development flow with vortex formed at the front local resistance member passes through the suddenly reduced cross-section and is compressed to rapidly,the vortex area is rapidly reduced,and the vortex strength is reduced,the vortex energy is converted into kinetic energy,so that the disturbance is broken to achieve a good local voltage stabilization.