| The 10,000-meter ultra-deep hole project is the main part of the deep exploration plan of the earth.It is faced with complex underground working conditions such as high temperature,high pressure,and high ground stress.All-metal turbodrills driven by high-temperature and ultra-high-density drilling fluid will be one of the main forms of coring operations.At present,the design theory of turbine blades based on high-density media is still blank.In this paper,based on the two-phase flow theory,the turbodrill blade energy output model research is carried out,and based on this,the multi-stage blade simulation and optimization design research are carried out,laying the foundation for the subsequent design of high-density turbodrill blades.In this paper,based on the basic equation of solid-liquid two-phase flow and the modified Bernoulli equation,a mathematical model of the coupling effect of two-phase flow viscous fluid flow and turbbodrill blades is established.A single-stage blade performance prediction model is proposed and extended to multi-stage blades,the calculation formulas of the torque,power and pressure drop of turbodrill under two-phase flow are deduced,and the effects of two-phase flow,fluid viscosity and fluid density on turbodrill output performance are qualitatively analyzed.Aiming at the target parameters of theФ127 coring turbodrill,the design of the radial dimension of the turbodrill joint is completed,and the geometric structure parameters of the blade are calculated,such as the leading edge radius,trailing edge radius,blade installation angle,leading edge taper angle,rear edge cone angle,relative pitch,etc.Based on the three-dimensional software SolidWorks,a three-dimensional model of the stator and rotor of the turbodrill was created,and the structure of the stator and rotor of the blade and the assembly design were verified,which laid the foundation for the subsequent turbodrill simulation.Based on the numerical simulation of FLUENT combined with the mathematical model,it can be seen that the viscosity of the drilling fluid has little effect on the torque and power of the turbodrill,but it will greatly increase the pressure drop of the turbodrill consumption and reduce the efficiency of the drilling tool;the weight of the drilling mud can significantly increase the torque of the turbodrill and power,to improve the performance of drilling tools,but at the same time will increase the pressure drop of hydraulic components;the smaller the solid phase particle size,the turbodrill torque and power increase,and the pressure drop decreases,but the change range is smaller.The composition of the drilling fluid should be rationally configured.When the driving mud conditions are:solid phase volume fraction 10%,solid phase particle size0.01 mm,density 1.4 g/cm~3,viscosity 16 mPa·s,The maximum torque of the200-stage turbodrill with a double section will be around 920 N·m,the peak power will reach 17 kW,and the turbbodrill pressure drop will be around 5 MPa,which basically meets the performance index ofФ127 turbodrill.In view of the fact that theФ178 turbodrill lacks mature blade shape,and theФ127 turbodrill has a similar working speed range,a method of contrast enlargement design is adopted.At the same time,optimize the basic structure parameters of the blade:increase the blade leading edge radius to 1 mm,the trailing edge radius to 0.6mm,and increase the number of rotor blades to 28,and the single-stage turbodrill working torque range is 19.66-28.72 N·m.At the optimal operating point,the turbodrill torque reached 22.56 N·m,which was relatively close to the target torque ofФ178 turbodrill of 28.05 N·m under the same conditions. |
PDF Full Text Request