Structure Design And Dynamic Simulation Of Hydrokinetic Hammer With Dynamic Pressure Feedback Using Virtual Prototyping Technology

Technology of Rotary Percussion Drilling exerts an important role in all kinds of deep hole drilling which aimed at drilling and collecting mining resources and oil-gas resources. It has the unique effect on increasing mechanical drilling rotation speed. The Chinese Continental Scientific Drilling Project which has caught worldwide attention just adopted such advance technologies to make the drilling sub-project achieved successfully. The application of the technology has quickened up the human's step that exploring the secret of the earth, and make the work of obtaining the resources from the depth of the earth efficiency.Hydrokinetic hammer is a kind of rock broken tool which use liquid as a work media to transfer and convert various type of energy. And it is one of the most important down the hole tools that applying Rotary Percussion Drilling technology. Meanwhile, it is also an under well drilling tool that our country owns independent intellectual property. In 70th of last century, with the joint efforts of Geological Team of Liaoning Tiebei and Geological Institute of Changchun, such kind of vibration device using fluidic elements to achieve dynamic pressure feedback for controlling come into being. It is called Hydrokinetic Hammer, and then it was applied in the field of geology prospecting drilling, to realize the perfect combination of hydraulic hammer and rope collecting core technology. It has been proved that using Rotary Percussion Drilling technology can increasing mechanical drilling speed, decreasing holes deviation, reducing drill head wear. On the other hand, there were some defects were discovered, such as the inefficiency while using energy, poor parts structure, missing chosen of the material, low stability and reliability and short lifetime as well. We must make a further analysis to eliminate the obstructions and gain the better performances. The early development of hydrokinetic hammer mostly based on designer's knowledge and experience, who connected the physical system with the actual element to study the dynamic properties. In order to examine the influence of the hammer's dynamic performance while changing the structural parameters and control mode many experiments must be done. However, such development not only costs a lot of human resources, material, money and time especially when it needs to change the hammer's structure and rebuild testing system, but also it is difficult to change system parameters and it has little chance of succeeding at a time. With the development of technology and the improvement of multi-body dynamic theory, it is possible to make a theoretical analysis of hydrokinetic hammer based on the precise dynamics equation of the piston. Influenced by the lag of fluidic element's theoretical research, the result of theoretical analysis is far away from practice. The mechanism of using model of similitude theory is not established in the field of our study, so the result is difficult to be quantified, and the dynamics coupling between element and piston can't be reflected precisely. The improvement of computer performance and the improvement of application software have promoted the progress of simulation techniques. With both experiment and theoretical analysis running into difficulty, computer simulation offers an ideal method for the development of hydrokinetic hammers. Since the mid 1990s simulation has got the extensive application in the development of hydrokinetic hammers, the analytical result of simulation has provided plenty of valuable reference data for the argumentation of structure schemes, the improvement of products, the performance prediction, the analysis of interior fluid characteristics and the diagnoses of constant faults. There four type of simulation methods being used to proceed dynamic analysis of hydrokinetic hammer:â‘ Programming with high-level language to process the calculation;â‘¡Building feedback control system model base on MATLAB;â‘¢CFD analysis of the internal flow filed of fluidic element;â‘£Make use of CAD/CAE/CFD software to carry through simulation. Comparing with experimental study, the theory research falls behind obviously. Some problems that need theoretical explanation were not solved till now. Such behind has caused the technology can not guide the innovation of the structure design and make the troubles shot in time.Therefore, the simulation analysis based on current theory was questioned in its scientificalness, authenticity, significance and values. Some times the simulation method even was excluded. The pace of improving product performance and new structure design were slowed down; the innovation concept was constrained as well. In recent years, projects established by some domestic research institutes shows that developing and accomplish Rotary Percussion Drilling technology and equipped tools have became the essential for researching advanced drilling technology. To secure our country takes leading position in the field of hydraulic research and its applications, the structure innovation of Hydrokinetic Hammer and related theory research will be the central focus among the researches. To design a new structure, a firm theory foundation is necessary. How to break through the bottleneck in shortest time? How to improve product performance? Maybe some experiences in related industries can give us a few enlightenments, the integrated dynamic coupling analysis based on CAD, CFD and Multi-body Dynamic simulation and Virtual Prototype technology should be the efficient way to develop new Hydrokinetic Hammer.This paper mainly introduces the Virtual Prototype technology and the specific application procedure of CFD in the process of structure innovation and dynamic simulation analysis and drawing conclusions. Using a generalized CAD method, it also explains the working principle of new type of Hydrokinetic Hammer. The structure design of new Hydrokinetic Hammers was accomplished in shorter time, and the feasibility of the design and merits of the performances were verified through dynamic simulation analysis conclusion. Technical reference for further research and test of new Hydrokinetic Hammers were provided. It is still earlier to say success before manufacturing actual prototype and then put into practicality. However the dynamic simulation analysis method based on Virtual Prototype technology has integrated much forwarding technologies of other subjects, gathered a lot of achievements together, its charming is exactly in it accurate foresee of the using performance and potential problems. As a triumphant application sample of Virtual Prototype technology, the paper can guide the research of Hydrokinetic Hammer into a new milestone, so as to push the further development of Rotary Percussion drilling technology.