Optimization Design And Simulation Of Downhole Turbodrill Blades

At present,the most widely used downhole power drilling tools are mainly divided into turbine drilling tools and screw drilling tools.Improving the performance of turbodrill and its wide application in drilling field can greatly improve drilling efficiency,which is of great significance to the development of drilling technology in China.Turbine drilling tool transforms hydraulic energy of drilling fluid into kinetic energy of turbodrill through its core component turbine.Drilling fluid flows through the turbine passage,pushing the turbine blade to obtain torque and transfer it to the turbodrill.The design of turbine blade profile plays a key role in the whole turbine design.Its performance determines the efficiency of hydraulic performance conversion of turbodrill.Optimum design of blade profile of turbodrill can improve the hydraulic performance of turbine,such as torque,efficiency,life and s Tableility,so it has high engineering practice value.In this paper,the blade profile of 127 mm diameter turbine is deduced in detail by Bezier curve,and the profile design software is compiled.The hydraulic performance of the blade is predicted by Fluent software.The key structural parameters of the blade are optimized by orthogonal test.The shape control parameters of the blade are optimized by genetic algorithm and CAD/CAE simulation.Then the blade profile with excellent hydraulic performance is obtained.Firstly,the axial velocity coefficient,impact coefficient and circulation coefficient of 127 mm diameter turbodrill are calculated according to its working conditions.Through these three dimensionless coefficients,the key structural parameters such as blade structural angle are calculated,and the blade profile equation is solved based on Bezier curve.Secondly,the threedimensional modeling software Solidworks is used to build the three-dimensional model of the turbine passage,and the performance of the turbodrill is predicted by CFD software Fluent to get its torque and efficiency.Then,taking the torque and efficiency as the targets,the key parameters such as structure angle and installation angle of turbine blade profile are optimized by orthogonal experiment.Thirdly,based on workbench platform,a closed-loop optimization design model including geometric modeling,meshing,numerical simulation and multiobjective genetic algorithm is es Tablelished to optimize the shape control parameters of turbine blade basin and blade back curve equation.Finally,combined with theoretical calculation and simulation analysis,a complete set of turbine blade optimization design method is formed.