涡轮钻具叶片优化设计与性能研究

Optimization design and performance research of turbodrill blades

摘要:

针对深部地热钻井中高温硬岩钻进效率低的问题，本文以?178mm高速涡轮钻具为研究对象，开展涡轮叶片的结构优化与水力性能研究。基于动量矩定理与能量守恒定律建立涡轮输出特性的数学模型，采用五次多项式曲线进行叶片型线设计，提出退化扭曲成型方法替代传统拉伸成型工艺，通过有限元流体分析对比优化前后叶片的速度场与压力场分布，搭建室内台架测试系统验证优化效果。结果表明：退化扭曲成型叶片实现了流道等宽度分布，改善了压力场均匀性，减小了涡流损失；实测结果与模拟趋势一致，验证了优化方法的有效性；额定转速下优化后单级涡轮输出扭矩提升65.58%，水力效率从67.92%提升至76.89%，压降降低4.27%。研究为提高深部地热钻井效率、降低能耗及延长钻具寿命提供了理论依据与技术支撑。

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.