Simulation Analysis And Structural Design For Duplex Reverse Circulation Drill Bit

The development of human society is inseparable from the supply of resources,the survival of subsistence are derived from mineral resources, and with thecontinuous development of society, demand and dependence on resources is alsogrowing. Forcing scarce resources to the deep mine exploration, mine developmentdifficult exploration. With the increasing difficulty of the task mineral resourcesexploration, prospecting needs more workers to drilling technology and drillingequipment research.Gas reverse circulation drilling technology, refers to the bottom of the boreholeusing a special device, such as a reverse circulation drill, cross-linker or packer, etc.,use the core exhaust gas-driven piston after the break after the drill cuttings from adouble-walled on the center channel back to the surface of a drilling technique.Conventional reverse circulation formation mechanism there are two, one is foreignand domestic research units packer portion blocking the formation of reversecirculation, Jilin University, represented by the research-based reverse circulationejector one is formed. But the comparative study of these two mechanisms currentlyreverse circulation abroad and the actual effect of reverse circulation less.The key factor in the formation of reverse circulation is reverse circulation drill.In this paper, SolidWorks Flow Simulation software for domestic ejector reversecirculation drill and packer drill two reverse circulation drill hole bottom flow fieldanalysis, research Two reverse circulation drill reverse circulation mechanism formedby the field test, Comparison of two further reverse circulation drill reversecirculation mechanism and reverse circulation effect. For simulation and field testproblems, in order to further enhance the effect of reverse circulation, The two reversecirculation drill binding, designed a new type of double-reverse circulation drill, reverse circulation drill and duplex structure parameters were optimized. In this paper,specific research contents and conclusions are as follows:(A) the use of computational fluid SolidWorks Flow Simulation software forboth reverse circulation drill hole bottom flow field simulation, to gain speed andpressure changes in the flow field of the hole bottom. Through the bottom of the holeflow field analysis, two reverse circulation drill mechanism developed reversecirculation form different: Ejector form of reverse circulation drill is to rely oninternal reverse circulation holes and bottom spray orifices for high-speed air suctionhole bottom and outer fluid suction; packer form of reverse circulation drill reversecirculation is to rely on the packer sleeve outer sealing effect empty forcing fluidoutflow from the central passage hole bottom. Chart simulation process data suggestthat ejector reverse circulation drill outer mass flow is positive, about20%of the inletmass flow rate of air flow has a certain ring pumping action; packer reversecirculation drill outer mass flow is negative, about20%of the inlet mass flow, reversecirculation is not complete, it will form part of the positive cycle.(B) conduct comparative field trials in Luoyang Luanchuan Molybdenum Mine,further study the mechanism of the two reverse circulation drill. Tests showed that thetwo forms of reverse circulation drilling can form a good reverse circulation, has a lotof debris and rock powder discharge speed at the gooseneck. Show ejectors andpackers have a positive effect on the formation of reverse circulation. But in theopening position, ejector reverse circulation drilling and packer of reverse circulationdrilling will return to dust phenomenon occurs in the drilling process. Problems oftheoretical analysis: Ejector reverse circulation drilling is due to appear back winddrill hole bottom end of the nozzle holes and rocks could not form a good ejectorstructure, the outer ring of the fluid suction decline; packer the emergence of reversecirculation drilling is due to return to dust formation complicated that the actual holediameter increases, the outer air passage flow area increases lead to reduced flowresistance, all of the gas failed to block the hole bottom.(C) for the formation of the outer ring is purely positive cycle appearing insimulation and field tests return orifice wind phenomenon, combined with the characteristics of the two drills, play to their strengths, to design a double-reversecirculation drill the ejector The Principle and the packer on the principle ofsimultaneous action in the drill. Simulation results show that double reversecirculation drill reverse circulation effect can be improved.(D) reverse circulation drill duplex structure parameters were optimized usingorthogonal experimental design.Scientific determination of the number of tests, thetest results were poor and analysis of variance, analysis of primary and secondaryeffects of the order of the parameters as well as the optimal combination of levels ofparameters. The important order double reverse circulation drill main structuralparameters on the Effect of Reverse Circulation is the number of the packer sleevelength, within the injection hole in the nozzle diameter, inner injection hole angle, theheight of the inner injection holes; and internal spray tilt angle and height of the innernozzle hole interaction hole also has an important impact on the double reversecirculation drill reverse circulation effect. Influence of various factors on the furtheranalysis, the actual bit design, select the structure of the final argument.