Design And Simulation Of New Portable Geophysical Drilling Rig

Geophysical prospecting boreholes on the Loess Plateau currently use artificial Luoyang shoveling,which is inefficient and labor intensive.In order to meet the requirements of the exploration drilling equipment in the Loess Plateau area,a new type of portable geophysical exploration rig is designed in this paper.The drilling rig uses the principle of air drilling to drill,without the need to stop drilling or drilling fluid,which greatly improves the drilling efficiency.The specific research contents are as follows:?1?The overall structure of the new portable geophysical exploration rig is gasoline engine+air compressor+gas pipeline+pneumatic motor+drill bit.Model selection and parameter calculation for engines,air compressors,hoses,pneumatic motors and drill bits.?2?The ABAQUS software was used to simulate the drilling process of four kinds of scraper bits,and the positive step scraper bits were analyzed and determined.Through orthogonal tests,four-factor three-level orthogonal tables were selected to simulate 9 groups of drill bits with different parameters.According to the test results,D₁B₂C₁A₁ is the optimal drill bit structure parameter,that is,the number of blades is 2,the number of blade steps is 3,the tip angle is 8°,and the thickness of the blade bottom edge is 2mm.?3?The influence of nozzle angle and nozzle diameter on the flow field at the bottom of the drill hole was analyzed by FLUENT software,and the optimal nozzle angle was determined to be 1°³°and the nozzle diameter was 5mm.Using the DPM model,the ability of the air to carry soil debris particles was further studied by changing the annulus inlet velocity and loess moisture content.?4?The FLUENT software is used to perform numerical simulation analysis on the air-solid two-phase flow law.The pressure distribution characteristics,velocity distribution characteristics and volume distribution characteristics of annulus air-solid two-phase flow are analyzed.The influences of gas inlet velocity,inlet soil debris concentration and soil debris particle diameter on the annulus flow field are also analyzed.