Stress Analysis And Optimization Of Support Of HVAC Pipeline In High-rise Civil Building Based On Finite Element Analysis

HVAC system makes the environment of working and living comfortable by controlling the air temperature and humidity in various areas of the building.The pipelines of HVAC water circulation system in high-rise building are of the characteristics of large pipe diameter,large vertical span,high pipeline pressure grade and so on,which puts forward high requirements for the safety and stability of the pipeline.Therefore,taking the HVAC pipeline of a high-rise building as the research object,the stress influence of the pipeline and the optimization of the support layout of the pipeline system were studied to ensure the safe and stable work of the pipeline in the project.It also provides guidance for the design and layout of HVAC pipes in similar high-rise buildings in the future.Based on the beam model of finite element method,the modeling and stress analysis of the pipeline in the high and low area of a high-rise building HVAC service apartment were carried out,and the influence of the basic parameters of the pipeline,such as working temperature,working pressure,diameter and wall thickness of pipes on the stress and offset of pipes were studied.The influence of flange installation position on the stress and deflection of pipeline was studied.the stress levels of horizontal elbows at various angles and spatial vertical elbows with different angles and types were studied.Based on the stress analysis results of the pipeline system,the practical engineering problems in the support arrangement of the pipeline,such as excessive stress at the pump mouth,emptying of the support and hanger,excessive displacement of the pipeline were studied.According to the arrangement principle of support and hanger and the strength and stiffness theory of support and hanger,the reference spacing of support and hanger and the design parameters of other pipeline support and hanger were calculated for the pipeline layout of civil high-rise building.The results showed that in the HVAC piping system of high-rise building,the high pipe pressure(greater than 2.5MPa)had a great effect on stress and displacement of pipes.The primary stress of pipeline increased significantly with the increase of pipeline pressure,and the pipeline offset of high pressure grade(5MPa)was 50% higher than that of low pressure(1MPa)pipe.When the pipe temperature was at 35~95 ?,the operating stress of the air conditioning pipe increased with the increase of the temperature,and the overall stress of the pipeline varied greatly.The primary stress of pipeline increased greatly with the increase of pipe diameter,and decreased with the increase of pipe wall thickness.With the increase of pipe diameter wall thickness,the primary stress of pipeline decreased and the secondary stress increased.The maximum allowable offset of the pipe increased with the increase of pipe length and wall thickness,and decreased with the increase of pipe diameter.The flange installation position had a great influence on the deflection of the pipe.As the flange position moved to the end of the pipe,the overall deflection of the pipe decreased and the horizontal angular displacement decreases gradually.With the increase of the angle of the horizontal elbow,the primary stress of the pipeline decreased linearly,and the secondary stress also showed a decreasing trend.The axial stress of the elbow decreased firstly and then remaind stable.The bending stress change trend of the elbow was similar to that of the secondary stress.The primary stress of 135 °vertical elbow was lower,and the secondary stress of 90 °vertical elbow was lower.Removing the support at the elbow of the pipe can increased the overall flexibility and natural compensation ability of the pipe and reduced the stress level of the pipe orifice of the equipment;for the local pipe with excessive deviation,The installation of guide bracket in the proper position could effectively limit the excessive deviation of the pipe,and it was feasible and effective to apply the hard connection technology between the equipment and the pipe in this project.