Analysis On Coupled Vibration And Research On Vibration Isolation Of Fracturing Pump Head And High Pressure Pipe Joints

Model 3000 fracturing truck due to its characteristics of high pressure level,large displacement,and unstable pulse flow,there are serious vibration phenomena in the process of fracturing.Fracturing manifold are wearing parts,and its high-pressure elbow is often exposed and burst,which seriously affects the safety and progress of fracturing site.The fluid-solid coupling vibration equation of fracturing manifold under the working conditions is established,and numerical simulation method is used to analyze the vibration characteristics of high pressure manifold and vibration isolation scheme.The empty pipe mode and the fluid-solid coupling mode of the high pressure manifold are analyzed,and the harmonic response including the first six modes of the high pressure manifold is analyzed.The transient response of high pressure manifolds at four,five and six operating conditions was analyzed,and the response of high pressure manifolds with and without considering the fluid-solid coupling of fracturing fluid was compared.Single factor method was used to study the displacement of fracturing pump and the load pressure of fracturing pump.According to the basic principle of mechanical vibration isolation,the vibration isolation scheme of fracturing high-pressure manifold is put forward,and the vibration isolation effect is verified.The results show that,considering the fluid-solid coupling,the natural frequency of each order of fracturing manifold increases,and the corresponding amplitude increases by 11% ~ 28%,and the modes of each order are basically similar.The displacement response is the largest when excited by the third-order natural frequency(72Hz).Under the fracturing condition,the maximum equivalent stress of the high-pressure manifold appears on the bend connected to the surface manifold,and the maximum deformation occurs in the straight section.The maximum equivalent stress and equivalent effect force generated by considering the fluid-solid coupling are significantly higher than those without considering the fluid-solid coupling at each tap of the high-pressure manifold.Considering fluid-solid coupling,the maximum stress peak increases by 42.42%,71.78% and 70.74%,respectively.The fluid-solid coupling effect has little influence on the overall deformation of the high-pressure manifold.When the displacement load of the pump head is large,the difference in the response to the deformation with and without the fluid-solid coupling effect is small,and the difference in the response value is within 1%.When the displacement load is small,that is,at the inflection point of sinusoidal displacement load,the response curve of the maximum deformation of the high-pressure manifold varies greatly with or without fluid-solid coupling,and the difference in the response is more than 3mm.Under operating conditions from three to seven gears,the variation of fracturing pump displacement has little influence on the maximum stress response of the manifold,while the maximum deformation response first decreases and then increases.The maximum displacement response value of the high-pressure manifold increases with the increase of the load pressure of the fracturing pump,and the maximum displacement response value of the high-pressure manifold also increases with the increase of the load pressure of the fracturing pump,and has a linear relationship with the load.By using rigid constraint and elastic constraint,the vibration of the high-pressure manifold under the excitation of pump head displacement can be reduced,and serious stress concentration can be avoided to a certain extent.