WCB阀门材料气固冲蚀实验与模拟研究OA

In the challenging domain of unconventional natural gas exploitation,specifically during the critical subsequent flowback and production phases,the reliable operation of blowdown valves is frequently compromised.These valves are subject to an extremely aggressive working environment characterized by high-velocity gas-solid two-phase flow,which inevitably contains hard solid particles such as aluminum oxide(Al2O3)proppants.This phenomenon induces severe erosion wear on the internal components of the valves,leading to a progressive deterioration of their structural integrity.Consequently,this often results in premature valve failure,dangerous fluid leakage,and significant unplanned downtime,thereby posing substantial safety risks and economic losses to the entire extraction process.Therefore,the work aims to conduct an in-depth investigation into the erosion characteristics and failure mechanisms of the WCB material,which is a common construction material for field valves.By utilizing a state-of-the-art high-speed gas jet erosion testing apparatus that complies with the ASTM G76 standard,the effect of key operational parameters is systematically evaluated.Furthermore,a robust and accurate predictive model is established through the integration of experimental data and computational fluid dynamics(CFD),which can ultimately serve as a scientific guideline for the anti-erosion design and lifespan assessment of valves in the demanding context of shale gas recovery.The research methodology commenced with erosion experiments conducted on a high-velocity gas jet rig complies with the ASTM G76 standard.The effect of three critical variables-impact angle(45°-90°),gas velocity(36-72 m/s),and particle mass flow rate(2-4 g/min)-on the erosion behavior of WCB was systematically evaluated.Upon exposure,the eroded samples underwent comprehensive characterization to decipher the underlying damage mechanisms.This involved the use of scanning electron microscopy(SEM)for micro-morphology analysis,white light interferometry for 3D surface topography,laser particle size analysis,and Vickers microhardness testing.Based on the acquired experimental dataset,the empirical constants within the Ahlert erosion model were recalibrated to derive a material-specific erosion rate equation for WCB.This customized equation was subsequently integrated into the boundary conditions of a CFD simulation framework,specifically governing particle-wall interactions,to establish a high-fidelity predictive model.The experimental findings revealed that the erosion rate of WCB increased monotonically with the rising impact velocity and particle mass flow rate.Conversely,a negative correlation was observed with respect to the impact angle,with the maximum erosion severity recorded at a glancing angle of 45°.Microstructural analysis indicated a distinct transition in the dominant erosion mechanism as the impact angle increased.At lower angles(45°-60°),the surface damage was characterized by a mixed-mode mechanism involving plastic ploughing and brittle micro-cracking.In contrast,at higher angles(75°-90°),the mechanism shifted towards surface compaction and delamination,primarily driven by particle embedding.The CFD simulations corroborated the experimental trends,confirming a positive correlation between inlet pressure and erosion rate.Furthermore,the simulations indicated that both particle size and particle sphericity exhibited a negative correlation with the erosion rate.It is concluded that the erosion mechanism of WCB material exhibits a typical ductile-to-brittle transition with the increasing impact angle,with brittle spalling becoming the predominant failure mode under normal(90°)impact conditions.The recalibrated erosion rate equation demonstrates high predictive accuracy,with the CFD simulation results showing excellent agreement with the experimental data.These findings provide valuable insights into the erosion behavior of valve materials and offer a reliable theoretical basis for the optimization of anti-erosion designs in shale gas production systems.