Modeling and Analysis of the Load Torque Acting on the Drilling Fluid Continuous Wave Generator

Abstract

Drilling fluid continuous wave(DFCW) generator is an advanced downhole instrument and has broad application prospects. The load torque acting on the DFCW generator has a great impact on the performance on the DFCW generator, and there is a lack of theory describing the load torque because of the irregularity of the rotary valve. In this paper, the drilling fluid flow area is divided into the curve flow area, the radial flow area and the axial flow area. The flow area of each part is divided into several meshes based on finite element theory, then the load torque acting on each part is calculated based on the fluid momentum conservation theory. The theoretical model is verified by combining the simulation and the experiment, and the effects of the discharge and the axial gap on the load torque are analyzed. The research results show that:(1) the theoretical model can be used to determine the load torque, (2) the amplitude of the load torque reduces as the gap decreases and increases rapidly as the discharge increases. The results can provide the theoretical guidance for the structure design of the rotary valve and the control system design of the drilling fluid continuous wave generator.