Design And Research Of Turbodrill Blades With Tandem Cascades

In 1980s,as the main power device in petroleum industry and one of the three major techniques in petroleum industry developing process,turbodrill developed sharply and became the famous downhole power drilling tool equally with the spiral drill tool because our country desires to exploit petroleum resources and develop the petroleum industry.The exploiting of the normal stratum resources is coming to an end,and there is a trend to exploit the unconventional oil and gas resources in intricate stratum,especially in the severe environment such as the deep well,high temperature and pressure.The spiral drill has superior performance in drilling.But it also has many disadvantages such as intense vibration and instability.With the features of high rotate speed,weak vibration and high temperature resistance,the turbodrill can accomplish a task with ease on all kind of conditions.At present,there are many explorations on turbodrill and they got abundant achievements in designing of the turbo blades.In the process of investigating the domestic and overseas turbo research situation,this context found that,compared with normal blade designing theory,the pneumatic turbo theory can more accurately reflect the inner flow field condition of the turbodrill.It can get more efficiency and torque with normal single row blade and the effect of turbodrill is largely determined by rotor blades.Based on these,this context comes up with a designing theory and a modeling analysis method using rotor.The specific research content is as follows:(1)Turbo blades designing theory researchThe research of pneumatic turbo blades designing theory bases on the designing of the long blades when design the blades.In the process of designing long blades,the change of blade parameters in radius direction is concerned.The ratio value of the average diameter of the turbodrill blade and the blade height is less than 7-10.This belongs to the scope of the long blade designing.So it can verify the blades designing feasibility.(2)Parameters designingWhen design the tandem cascade parameter,firstly design a single row blade as the tandem cascade front blade based on the pneumatic turbo blade theory and long blade designing.And then use the space tandem cascade experience combined shunting blade modeling to confirm the cascade parameter.(3)Blade modelingDesign the tandem cascade blade to model in AUTOBLADE of NUMECA software.And respectively import or select the end wall type line,stream surface type,blade section parameter,product stack rules and main blade type.Then check the tandem cascade model structure and shape preparing for the later numerical value analysis.(4)Optimize the turbo tandem cascade by flow field simulationAfter making the model,confirm the front and post blades parameters of tandem cascade and adjust the parameter value to make the models of multiple models.Then adopt the AutoGrid 5 model in NUMECA software to analyse the flow field simulation.We can get the turbo performance curve graph in different parameters and optimize them according to the performance chart.And analyse the speed and pressure nephogram and then conclude the flow rules.(5)Analyse the variable working condition of the optimized tandem cascade and compare the single row blade.As for the optimized blade,according to steps above,we can stimulate the flow field.Then we can get the speed nephogram and pressure nephogram in different rotating speed.And analyse that how the fluid flow in the blades and conclude the flow rules;then draw the turbo feasibility curve graph.According to the curve graph,we can analyse that the rotors of this blade type can get best working performance on the condition of high rotating speed.Finally,we can stimulate the flow field based on the designed single row blade and compare with the tandem cascade.Then conclude the advantages and disadvantages of the tandem cascade.