| In this paper, based on gas-solid two-phase flow model of Euler and Lagrange, the flow model and erosion model were established for high speed gas carrying cuttings in blooie line of gas drilling, and a series of CFD numerical simulations were carried out to reveal the flow field characteristics, the deformation, Von mises stress distribution of blooie line and erosion rule. On that basis, an anti-eroded device was designed and verified by simulation. The analytic works are as follow:(1) According to actual conditions of gas drilling, the gas motion equations in blooie line were derived. The right turbulence model and a near wall flow model, which suited for high-speed gas flowing in gas drilling blooie line, were selected. The DPM model and erosion model were determined to research the erosion characteristics at the bend segment. Besides, the CFD numerical method and the fluid-solid interaction method were briefly introduced in this paper.(2) The flow distribution at the bend segment was studied, considering the critical influence factors of pipe diameter, angle of bend, bending diameter ratio and inlet velocity, the changes of pressure field and velocity field and the wall shear stress along the bend segment by those factors were revealed.(3) Considering the flow characteristics, the distribution of deformation and Von mises stress at the bend segment were analyzed by simulation. And the influence of bending diameter ratio and inlet velocity to deformation and Von mises stress were obtained.(4) The erosion rate distribution in bend was discussed. On the basis of the flow field characteristics at the bend segment, the influence of structure parameters (diameter, angle of bend, bending diameter ratio) and operating parameters (inlet velocity, particle concentration, particle diameter) on the erosion rate was brought to light.(5) Considering erosion distribution and influent factors, an anti-eroded elbow was designed and qualitatively analyzed its preventing erosion characteristics. |
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