| Pipeline is an important component transmission of fluid in power plants.Boiler pipeline is prone to rupture and explosion in the environment of high-temperature and high-pressure for a long time,which may endanger the operation of power plant unit and even cause casualties.In order to research the on-line detection technology of boiler pipeline leakage and judge the occurrence of leakage and locate the leakage point timely,then conduct theoretical and simulation experiments on pipeline leakage.The propagation characteristics of vibration sound of pipe wall caused by pipeline leakage are related to the material parameters and geometric parameters of the pipeline.It is of great significance to reveal the generation and propagation characteristics of vibration sound waves at the leakage port for online monitoring technology of boiler pipeline and timely locating leakage to reduce the accidents caused by pipeline leakage..When pipeline leakage occurs,the internal fluid of pipeline,solid of pipeline structure and external fluid of pipeline are all the media of leakage sound wave propagation.As the acoustic mechanism involves the coupling analysis of fluid mechanics,thermal and other fields,the acoustic mechanism caused by pipeline leakage is too complex.Therefore,it is simplified to discuss and study the acoustic field radiated by a small piston vibration source on the wall of a cylindrical pipe in the surrounding space.The results show that the sound pressure level of the far field has the same law of change in the direction of polar Angle at different frequencies.The higher the vibration frequency is,the more the peak value of relative sound pressure level is,and the more obvious the interference phenomenon is.For the vibration source with the same shape and the same height and different half-angle width,the larger the half-angle width is,the larger the maximum value of the relative sound pressure level in the surrounding space will be.In the x-y plane,the vibration sources of different shapes have the same directivity feature,and the vibration sources of different shapes on the cylinder wall mainly affect the sound field distribution along the polar Angle.In this paper,Computational Fluid Dynamics method was used to simulate and analyze the flow field of high-pressure pipeline leakage,and the simulation results were verified by the mass flow theory formula.When the flow field simulation is completed,the unidirectional fluid-solid coupling simulation analysis is performed on the flow field and the pipeline structure.Experimental research on pipeline leakage under different conditions has been carried out.The results show that with the same leakage pore size,as the fluid pressure increasing in the tube,the sound pressure level generated on the tube wall increasing.Timing,as the leakage aperture increases,the peak frequency of the wall vibration decreases. |
