Optimization Design and Analysis of Polymer High Efficiency Mixer in Offshore Oil Field

The degree of polymer-water mixing in high-pressure pipelines on offshore oilfields usually influences the polymer solution’s performance. To realize efficient mixing of the polymer mother liquor with dilution water in the high-pressure pipeline, a high-efficiency mixer is designed and optimized. The designed mixer consists of four parts: a T-shaped pipe as the main body, an inlet flow-splitting plate, a stainless-steel flow-guiding tube, and an outlet flow-splitting plate. Mathematical models are built by using computational fluid dynamics (CFD) and the mixing effects are compared by using Fluent. The research results show that compared with conventional T-shaped mixers, the designed high-efficiency mixer has better mixing performance and increases the mixing rate to 80%. To optimize the mixing rate, the length of the stainless-steel tube is increased and the tube is perforated to guide the flow. The result shows that boring holes along straight lines around the tube can achieve good optimization effect and increase the mixing rate to 95%. The designed high-efficiency mixer can effectively improve the dissolving efficiency and solve problems in polymer-water mixing in the high-pressure pipeline.

Application of a Hybrid RANS-LES Method to Free Shear Layers

This paper presents the application of the XLES (eXtra Large Eddy Simulation) method to relevant test-cases. The mixing between two boundary layers and between a wake and a boundary layer are discussed. The first test case considers the mixing layer that forms at the end of a splitting plate. Two boundary layers with different free-stream velocities flow on the upper and lower side of a flat plate and join at the trailing edge forming a free shear layer. The second test case represents a mixing between the 2-D wake originating downstream an airfoil and the 2-D boundary layer developing over a flat plate placed beneath the airfoil. This application is representative of flows over multi-element configurations where the wake coming from the slat merges with the boundary layer of the main component. The method has shown to be effective reducing the modelled turbulence and providing resolved turbulence in the regions of the field treated in LES mode. The “grey-area” issue has been highlighted. This is likely connected to the stochastic character of the model.