| The application of multiple-pipe high pressure jet grouting technology is more and more widely.As one of the core equipment of rotary jet grouting in the system,nozzle has important significance to the dynamic performance and the distribution of nozzle internal and external jet flow field.According to the different uses,the different structure nozzles are designed.Good jet nozzle structure can acquire ideal jet flow.Therefore seeking better nozzle structure and optimizing the structural parameters of the nozzle has become the emphasis and difficulty for domestic and foreign scholars.This paper mainly involves two different types of fluid jet nozzle based on the research contents,respectively are multihole water jet nozzle and rotational flow cement jet nozzle.For the multihole water jet nozzle,designing three different structure of core flow channel mainly,and establishing their three-dimensional physical model for each nozzle.The numerical simulations is based on CFD fluid analysis software,setting up the gas-liquid two phase flow model,and using the Mixture of multiphase flow analysis method in coupling speed and pressure of the multihole water jet nozzle.According to the analysis of simulation data,the structure of the elliptic flow channel nozzle has better hydraulic characteristics,larger core speed and better fluidic beam concentration than the other two kinds of structure.When the auxiliary jet is at the axis distance of D = 8 mm between the core jet hole and the auxiliary injection hole has better water hydraulic characteristics and the less influence on the core jet.For the rotational cement jet nozzle,establishing gas-solid two phase flow model,and using the VOF method of multiphase flow analysis,by comparing the effect of rotational flow of different rotation angles on the external flow field,and it is concluded that with the increase of rotation angle jet radius is increased and the cement jet is more divergent,is also beneficial to mix hole cuttings and mud with cement equably,through simulation analysis under rotation angle 60 ° or so,the effect of rotational cement jet nozzle is better.Finally based on the laboratory existing conditions,those three kinds flow channel structure of multihole water jet nozzle executed experimental work in the laboratory,and respectively demonstrated outside jet flow field distribution of the water jet in the air,according to the actual working status of nozzle to verify the rationality of the design of the nozzle.It's benefit to make auxiliary research for jet. |
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