Design And Performance Simulation Of A Small Size Hydraulic Turbo

In petroleum drilling,hydraulic drag-reducing Oscillator can transform static friction between drill string and borehole wall into dynamic friction,improve the transmission effect of drill pressure and increase the mechanical speed,which is applied more and more.However,screw-driven hydraulic drag-reducing oscillator can not fully meet the needs of modern drilling because of its long length,high pressure drop,difficult sealing and poor high temperature resistance.Hydraulic turbo has the advantages of compact structure,high temperature resistance and high rotational speed.There is a lack of small diameter products that 89 mm turbodrill is successfully developed in China until 2016.In order to overcome the shortcomings of the hydraulic drag-reducting oscillator,this paper attempts to develop a small size hydraulic turbo to replace the screw-driven motor.This paper summarizes the blade parameter modeling method based on quintic polynomial curve on the basis of studying the design method of general large-size turbo blade profile.The blade profile adjustment is fle·ible and the calculation is simple.By using quintic polynomial blade parametric modeling method successfully designes basic small size turbo and carries three-dimensional modeling.The stator outer diameter was 76 mm.By using Fluent simulates the hydraulic performance of the designed basic small-sized turbo and obtains the internal flow field and performance parameters.When the efficiency is highest,the rotating velocity is 1718.87 rpm,torque is 1.027 N ×m,output power is 184.86W;When the rotating velocity is 143 rpm,torque can reach 1.73 N ×m.The orthogonal analysis shows that the leading edge radius has a significant effect on the output torque.The larger the leading edge radius is,the larger the output torque is.The influence of the rear wedge angle on the blade output torque is more significant.The larger the rear edge radius is,the larger the output torque is.Blade height has a very significant impact on the hydraulic efficiency of the blade.The higher the blade is,the higher the hydraulic efficiency of the blade is.The leading edge radius has a significant effect on the pressure drop.The pressure drop increases with the increase of leading edge radius.The recommended values for turbo blades parameters are: front wedge angle is 15°,rear wedge angle is 15°,leading edge radius is 0.6mm,trailing edge radius is 0.3mm,blade height is9 mm.The numerical simulation of the turbo hydraulic characteristics of the optimized structure shows that its performance inde· is superior to that of the basic turbo,and the ma·imum efficiency is 80.26%.The study of drilling fluid parameters shows that the turbo torque increases with the increase of drilling fluid flow rate and density.When the drilling fluid viscosity increase,the turbo torque decline.The turbo pressure drop increases with the increase of drilling fluid flow rate,density and viscosity.Turbo efficiency increase initially and then decrease with the increase of drilling fluid flow rate.Turbo efficiency increases with the increase of drilling fluid density,and it presents non-linearity.Turbo efficiency decreases with the increase of drilling fluid viscosity.