Study On Fluid-Solid-Thermal Multi-field Coupling Simulation Of Rotary Tail Pipe Hanger Bearing

With the continuous development of domestic oilfield development and tailpipe cementing technology,the performance requirements for cementing tools such as rotating tailpipe hangers are continuously increasing.The rotating tail pipe hanger bearings used as important part which is the connection between the upper joint and the lower casing play an important role in this system.China's self-developed rotating tail pipe hanger bearings are full-loaded tapered roller thrust bearings.In the actual working process,due to the complex working conditions such as high temperature,high pressure,drilling fluid flushing,etc.,the bearing will suffer premature failure caused by shaft ring breakage,rolling body wear and breakage.In view of this phenomenon,this paper focuses on the analysis of the actual working conditions of the bearing,sorting and categorizing the actual working conditions into three physical fields of flow,solid and heat,thereby transforming the influence of working conditions into three physical field coupling effects.According to the actual situation of each physical field,the finite element coupling scheme of this bearing system was formulated.Through numerical simulation,the performance of the bearing in the underground working environment was simulated,and the effect of environmental parameters on bearing performance was analyzed.The main contents of this paper are as follows.(1)The contact analysis,friction analysis and dynamic load analysis of the bearing are carried out based on Hertz contact theory,tribology theory and dynamic theory.The formula of Hertz contact formula and internal friction work formula of the bearing is derived.And the dynamical equations of this series of bearings are established.The bearing internal contact and friction related parameters,bearing motion components and torque variation rules are obtained.(2)Based on the heat transfer theory and the thermal network method,the thermal network model and the Simulink calculation model are established for the series bearings and the surrounding environment system,and the steady temperature field and transient temperature field of the bearing are obtained.(3)Through the finite element method,a multi-field bearing coupling scheme was established.The fluid-solid-thermal field coupling problem is transformed into a fluidsolid coupling heat transfer problem outside the bearing and a thermal engine coupling problem inside the bearing,depending on the actual operating conditions of the bearing.The data transmission was conducted through the fluid-solid coupling heat exchanger interface,and finally the performance of the rotating tail pipe hanger bearing under the coupling field was obtained.The bearing performance under coupled and uncoupled fields is also compared.It is found that the coupling field increases the bearing equivalent stress,structural deformation and contact stress by 6.48%,39.78% and 13.48%,respectively.Then we came to the conclusion that “the coupling field conditions need to be considered when designing bearings”.Through the research of the theory and simulation of this paper,it can provide some theoretical basis and reference for the further study of this kind of bearing,and then make the rotary tail pipe hanger stable operation in the cementing process and improve the cementing quality and efficiency.