Optimization design and performance research of turbodrill blades

Abstract:

To address the issue of low drilling efficiency in high-temperature hard rock formations during deep geothermal drilling， this paper investigates the structural optimization and hydraulic performance of turbine blades using a ?178 mm high-speed turbodrill as the research object. A mathematical model for the output characteristics of the turbodrill was established based on the moment of momentum theorem and the law of conservation of energy. The blade profile was designed using a quintic polynomial curve， and a degenerated twisted forming method was proposed to replace the traditional stretch forming process. Finite element fluid analysis was employed to compare the velocity and pressure field distributions of the blades before and after optimization， and an indoor bench test system was built to verify the optimization effect. The results indicate that the blades formed by the degenerated twisted method achieve an equal-width flow channel distribution， improve pressure field uniformity， and reduce vortex losses. The experimental results were consistent with the simulation trends， validating the effectiveness of the optimization method. At the rated speed， the output torque of the optimized single-stage turbine increased by 65.58%， the hydraulic efficiency improved from 67.92% to 76.89%， and the pressure drop decreased by 4.27%. This study provides a theoretical basis and technical support for improving deep geothermal drilling efficiency， reducing energy consumption， and extending the service life of drilling tools.