Numerical And Experimental Research On Dynamic Hydrocyclone With Pressurized Overflow

For the extraction of oilfield more and more seriously containing mud-sand and difficultly removing mud-sand from it under low pressure, this paper proposes a new type dynamic hydrocyclone which can realize low pressure feeding and rise up the outlet pressure of overflow phase. The dynamic hydrocyclone combines with advantages of static hydrocyclone and centrifugal pump, it can not only make the feeding enter into under lower pressure and complete high efficiency separation of the two-phase, but also realize pressurization function to the overflow fluid, in order to reduce the power supply of the follow-up technology process.The paper adopt technical route of numerical calculation and experimental combination. The paper establishes the dynamic hydrocyclone’s geometric model in the help of Pro/E three-dimension modeling software, and applies CFD numerical simulation software FLUENT, selecting RNGκ-εturbulence model to simulate internal single and continuous phase flow field under different operation rotate speed and inlet flow, and to simulate the influence of having or no overflow rotating impeller even adding its diameter on the pressure of overflow outlet fluid. Then, the paper adopts the DPM Lagrange random track model to simulate liquid-solid two phase flow on the basis of single phase flow field, in order to study separation performance of dynamic hydrocyclone. After machining experiment model machine, the author sets up a complete set of experiment equipment system in the laboratory and conducts the clear water experiment and water-sand separation experiment, focusing on researching the influence of the rotate speed, inlet flow and operation split on the performance of pressure drop and separation.FLUENT numerical simulation and experiment study show that the proposed dynamic hydrocyclone is reasonable structure, dismounting convenient and operation stable. Its internal flow field is very similar to the static hydrocyclone, and the change of rotational speed and inlet flow will not affect the regularity of the internal flow field distribution, just having a change in the numerical size. The rotating impeller of the overflow structure can completely realize the pressurization function to the overflow outlet fluid, to reduce the power supply of the follow-up technology process unit operation. Besides, by adding impeller’s outside diameter and rotational speed can further improve the outlet pressure of overflow fluid, but the increase of the equipment’ consumed power is very small, the maximum not more than20%. The new type dynamic hydrocyclone’s separated particle size d50is18μ limited particle size d98is65μ, and these prove that the dynamic hydrocyclone can complete the liquid-solid separation. The solid bar inserted in the center of hydrocyclone can reduce the inner energy loss and steady the flow field, to help enhance the separation efficiency. The dynamic hydrocyclone is always able to maintain higher modification separation efficiency in a broader range of inlet flow fluctuation and operation split, the highest can be97.3%, and improving the rotational speed not only can achieve better separation effect but also realize further pressurization of overflow outlet fluid.