泡沫钻进流体循环用消泡器设计与数值模拟分析

Structure design and numerical simulation of a mechanical foambreaker for foam drilling fluid recycling

摘要:

高效、经济、环保的消泡技术是泡沫钻进流体循环利用的基础。根据气体引射器原理，设计了一种新型旋内喷式机械消泡装置，以压缩空气为动力介质，联合真空负压、冲击剪切、充气饱和及减速增压扩散4种作用方式快速消泡，实现泡沫流体的循环利用。利用计算流体动力学软件FLUENT对消泡器内部速度和压力流场进行了数值模拟分析，结果表明：旋内喷式消泡器内部产生两个相邻重叠的真空负压区域，能够对外界流体产生巨大的抽吸力，抽吸量是入口压缩空气质量流的1.6倍左右；当入口压缩空气的质量流为0.1 kg/s时，消泡器中心最大负压值达到了21 kPa；在交汇式喷射孔的多股射流交汇碰撞点附近，由于速度的提升，形成了一个更大的负压区域，对消泡产生积极作用。

Abstract:

Efficient, economical and environmentfriendly defoaming technology is the basis for achievement of foam drilling fluid recycling. A novel rotary and spray type of foam breaker was designed according to the gas ejector principle by which compressed air was used as the power medium combined with vacuum negative pressure, impact shear, aerated saturation and pressure diffusion for quick defoaming and foam fluid recycling. The computational fluid dynamics software FLUENT was employed to simulate the flow characteristics inside the foam breaker. The simulation results showed that the rotary and spray type of foam breaker generated two adjacent overlapping vacuum negative pressure areas inside and can produce great suction force on the outside flow with the suction amount about 1.6 times the compressed air at the inlet. The maximum negative pressure can reach 21kPa inside of the foam breaker when the mass flowrate of the compressed air flow at the inlet was 0.1kg/s, generating a larger area of negative pressure near the collision point of multiple jets from the converging nozzles due to jet speed boost which is conducive to defoaming.