Mechanics Analysis And Application Of The Small Flexible Pumping System

The small flexible pumping system is mainly composed of the small pumping units and flexible rod string. Using multipoint constraints and assemblies technique, beam-shell-solid assembly model is established, and the transient loads is considered. Using newmark method, transient dynamic problem of the small pumping units is researched. The result shows that in the load of 3kN~20kN, every components meets the strength condition, the left-right support is better than the front-back support. The nonlinear transient dynamic model of the flexible rod string and elastic link is established, the model consider the flexible rod string as tension-only spar LINK10 and pump as COMBIN40.The calculation of five wells shows that the theoretical load is basically consistent with test load, the static load relative error is less than 5%, the relative error of maximum and minimum load is less than 10%. Influencing factors of pump stroke shows that the young's modulus of flexible rod string should be more than 80GPa, the stroke of suspension point should be 2m~3m and the velocity be 1min-1~3min-1, the length of weight rod be 38m~47m, the results can meet the transient dynamic forecasting and design requirements. By fluid-solid coupling analysis method, the damping factor of the different eccentric rod string in the laminar and the turbulent is calculated. The results shows that the numerical result of the laminar damping factor is in accord with the theoretical result and relative error is 0.60%, which provide a theory basis to calculating the damping force of the eccentric rod string.