Valve Plate Geometry Optimization for Torque Reduction in Continuous-Wave Mud Pulsers: A CFD Study

Continuous-wave mud pulsers enable real-time downhole communication during drilling; however, high actuation torque markedly increases energy consumption and limits deployment depth. In this study, we investigate valve plate geometry optimization for torque reduction through systematic CFD simulations using the SST k–ω turbulence model and analyzed the coupled effects of opening angle (20–30°) and chamfer height (4.0–6.0 mm) on hydraulic performance. The results reveal a previously uncharacterized torque-reversal phenomenon: introducing a chamfer shifts the torque zero-crossing point forward by up to 10°, fundamentally altering the torque–angle relationship. The main contribution is the establishment of quantitative correlations between geometric parameters and the torque–pressure decoupling mechanism, achieving a 45–60% reduction in peak torque while maintaining differential pressure within acceptable ranges for signal generation. Detailed flow-field analyses show that chamfers modify local velocity gradients and pressure distributions on valve surfaces, reducing flow resistance through improved momentum exchange. Dimensionless correlations between geometric parameters and performance metrics are developed, providing quantitative design guidelines for energy-efficient valve plates. Validation against baseline designs confirms that optimized geometries substantially reduce actuator power requirements without compromising signal quality. These findings provide practical design strategies for next-generation mud pulsers for deep well and extended-reach drilling, where energy efficiency is critical. The proposed optimization framework, based on the identified torque–pressure decoupling principle, is also applicable to other rotary valve systems requiring simultaneous optimization of actuation energy and functional performance.