The Retrofic Design Of Fluid Efflux Hammer And Its MATLAB Simulation Computation

Fluid Efflux Hammer has a good name in the field of drilling forits particular style and specific performance, from its burning.However, in the application process, with the changing of workingcondition and specific operating requirement, its advantageswas not made full use, and some interior structure membersaccumulated some questions when applicated.Based on the call of times for Fluid Efflux Hammer, the paperanalyzes the questions when test in CCSD, makes a design to retrofitsome parts of the exiting 89-type Fluid Efflux Hammer, addsstructure to protect Bi-stable Fluidic Element and to shuntexcess flow, designs a structure to storage and buffer hammer,improves feeder current holes, changes the type of the exitinginside tube or inner casing and its sealing, assembling way,modifies the original expansion joint to change the method ofprevent from impacting empty.On the base of design, the paper makes an analyzing the keystructure-Bi-stable Fluidic Element, using jet current theory, fluidmechanics principle, .etc, to computer its flow field parameters, and getthe flow and pressure controlling functions of attachment andno-attachment side`s evacuating way, outputting way, signal way, outlet,etc. At the same time, making reference with Newton`s laws of motionand fluid mechanics principles, the paper analyzes to get the piston`stheoretical moving controlling functions of the impaction system withfeeder current holes and the storage and buffering structure, invariant moving steps. The paper Uses MATLAB language and its major tool-Simulinkto simulate the element and hammer`s impacting system. Aftercomposing m file and s function and simulating, majorconclusions are following: 1.Passing the attachment point ,the fluid jet is still very thin; 2.With the improving controlling flow, the jet`s declinationangle was the vest effected, the arc length of center line wasdecreased, but the amplitude was little; the arc radius decreasedmore quickly. 3.When the element worked normally, the signal way at theattachment and no-attachment size had flow circulating. At theattachment size, the flow velocity was 0.4801m/s, whileno-attachment size, the flow velocity was 1.2453m/s. 4.When working normally, the pressure at no-attachmentvaried slowly, which do advantage to element attaching stably.When switching, the pressure enlarged firstly and thendecreasing. 5.When working normally, the jet`s entraining flow comes fromthat signal flow and outputting flow. 6.When element switching, the outlet generated water shockpressure, and the pressure was some 5 times more than thegeneral pressure. When the pressure reached signal way, thesignal way created shock pressure too, which was 25-30 timesmore than the general one. So large flow ejected out of the signalspout , which made jet fluid generate large declination angle andbended the flow line. At the same time, large flow filled up thegeneral low-pressure eddy zone, which increased the eddy stresssteeply. When the eddy stress exceeded the pressure outsize thejet flow, and maintained for a little time, the jet stream wasattached to the other side of element stably. So we canconcluded, the jet`s switchment was the combined result of themomentum of jet from signal spout and the eddy flow. 7.The simulating result of the impacting system with storageand buffering structure and feeder current holes indicated: In thecase of returning, when piton passed feeder current holes, whichconnected the upside pressure cavity with the outsize one, theflow in the upsize cavity leaked off from feeder current holes, asreduced largely the piston`s returning resistance. For returningresistance decreased, piston got large moving velocity whenleaved holes. And this velocity was stowaged by thestorage-buffering spring. For contacted to the spring, the velocityof piston varied severely, which resulted the flow velocitychanging suddenly which created the stroke pressure to switchover. The huge stroke stress was storage by the spring. Itindicated that feeder current holes play important role in reducingthe piston`s returning resistance, decreasing returning time, andincreasing stroke frequency. Switching over, the pressure downside cavity decreased, thestorage and buffering spring began to released its energy tomotivate piston stroking. So piston got a huge acceleration at thebeginning of stroking case. For spring activated the piston tosome case, element needed to drive the still piston, as that theoutlet had a high speed at the beginning. After storage energyexhausted, piston reached the feeder current holes. Computingresult said now the upside flow did not keep up with piston, so...