CN105718682A - Grinding simulation method for grinding liquid particles and workpieces under mesoscale condition - Google Patents

Abstract

The invention relates to a numerical value simulation method for grinding liquid particles and workpieces under the mesoscale condition.The method comprises the following specific steps that 1, a calculation model is set up, and the initial condition is set up; 2, the boundary condition of the calculation model is set; 3, a model grid is divided; 4, simulation analysis is carried out; 5, meso state simulation is studied by means of machining parameters, wherein (a), the influence on abrasive particle machining from different concentrations is studied; (b), the influence on particle ground and machined parts from machining temperature is studied; (c), the influence on the particle ground and machined parts from the machining speed is studied.By means of analogue simulation machining, the reference is provided for the influence on abrasive particle flow machining from particles under the meso state, the theoretical support is provided for the actual production machining process, the defects generated when particle grinding is studied under the macroscopic and microscopic states are made up, and the theory of the particle ground workpieces is perfected.

Description

The grinding analogy method of lapping liquid granule and workpiece when a kind of meso-scale

Technical field

The present invention relates to machining grinding technique field, be specifically related in a kind of meso-scale lapping liquid granule and the grinding analogy method of workpiece.

Background technology

And structure cell cluster sunykatuib analysis to lapping liquid granule theoretical according to Dissipative Particle Dynamics, carry out with elementide be main particulate form, the grinding probing into lapping liquid granule and workpiece in conjunction with abrasive Flow Machining technology.And first Dissipative Particle Dynamics Simulation method is the Mesoscale Simulation technology of a latest development, it is to study complex system mesoscopic structure, is a kind of new analogy method of contact macro-scale and micro-scale.The present invention is theoretical and numerical algorithm according to Dissipative Particle Dynamics, carries out the Simulation of Grinding of lapping liquid granule and workpiece in meso-scale.Macrovision analog (grain diameter yardstick is more than 1 micron), is mainly used in Chemical Process Simulation, machine-building and processing and other fields；Microcosmic Simulation (grain diameter yardstick 0.1 nanometer to 10 nanometers), is usually used in the physical modeling of the MOLECULE DESIGN of medicine, chemism repercussion study and cohesion form；Mesoscopic simulation (grain diameter yardstick is between 10 nanometers to 1000 nanometers), be mainly used in liquid crystal, balance each other, the research of the aspect such as material property, it actually plays bridge beam action between the kinetics of framework rapid molecular yardstick and the thermodynamics of macro-scale at a slow speed.And the scale simulation of abrasive Flow macrostate, research worker has been had to participate in research, and be verified, the simulation of micro-scale has been also applied in Ultra-precision Turning, and the simulation in meso-scale does not relate to yet, therefore, this chapter carries out the simulation in abrasive Flow meso-scale and has innovative significance, and can understand the essence of abrasive Flow Machining under Mesoscopic simulation.The present invention chooses the abrasive particle lattice in meso-scale and carries out grinding simulation, analyses in depth the impact of abrasive particle grinding wall velocity field, temperature field, density field, Turbulent Kinetic and abrasive particle track；Carry out the abrasive particle Mesoscopic simulation analysis to wall under different processing conditions again.Fig. 1 gives the schematic diagram of granule atomic group grinding work piece.

From schematic diagram, it can be seen that the original form of the lapping liquid granule atomic group under meso-scale, piston movement in hydraulic cylinder, through grinding work piece inner surface, in carrying out grinding process, the dispersion of atomic group and re-uniting, reach the effect of burr and the rounding removing work piece inner surface, thus reflecting the lapping liquid abrasive particle structure cell cluster models impact on grinding under meso-scale, provide theoretical direction to actual production processing.

Discrete Phase Model (DiscretePhaseModel, DPM) carries out under Lagrange viewpoint, and it is to be calculated with single particle for object, and continuous phase calculate be under Euler viewpoint with spatial point for object of study.Such as, in the calculating that hydraulic oil mixes with natural gas phase, its air is continuous phase, its result of calculation be with the temperature in spatial point, density, pressure variable distribution form show；And oil droplet therein is based on discrete phase, by simulating the track of oil droplet, speed, stress as the final form of expression.Therefore the model of discrete phase can as in meso-scale select granule best model, and using the method as simulation analysis.

Summary of the invention

The method for numerical simulation of lapping liquid granule when it is an object of the invention to provide a kind of meso-scale and workpiece grinding, in order to grind for workpiece better and carry out digital simulation, improve research effect.

To achieve these goals, technical scheme is as follows.

Lapping liquid granule when a kind of meso-scale and the method for numerical simulation of workpiece grinding, specifically comprise the following steps that

(1) computation model is set up and initial condition: choose Diesel engine atomizer part, access road macropore port diameter is 4mm, the tapered shape of spray nozzle front end, being uniformly distributed six spray orifices, hole diameter is 0.16mm, carries out three-dimensional drawing by CATIA, to the part body portion being made without simulation, simplify, retain macropore inside and aperture nozzle flow channel, obtain its passage geometric model；By setting up atomizer three-dimensional entity model and geometric model, lay the foundation for carrying out abrasive particle grinding analysis, mapped by three-dimensional software, after structure distribution is reasonable, then carry out FLUENT analogue simulation analysis；

(2) setting of computation model boundary condition, specifically includes:

A () entrance boundary condition: entrance boundary condition refers to the flow variables determining porch, it includes speed entrance boundary condition, pressure entrance boundary condition and quality entrance boundary condition；Its medium velocity entrance boundary condition is the scalar that flowing velocity is relevant with the flow properties of flowing entrance.And be Discrete Phase Model according to selected model, therefore need the situation setting continuous phase with discrete phase；

Continuous phase: atomizer passage inlet port adopts speed condition for import, sets now import department's abrasive Flow and as turbulence state, selects k-epsilon model in Model, select Realizable, confirm in k-epsilonModel；Energy model is chosen EnergyEquation activation energy equation；

Discrete phase: being simulated processing when carrying out different-grain diameter, different temperatures, friction speed, the concentration chosen is 10%, when carrying out variable concentrations simulation, chooses 2%, 4%, 6% and 8% relatively reasonable respectively；

(b) export boundary condition: by abrasive Flow grinding atomizer physical condition it can be seen that come round in the port of export and the external world, therefore be set as free export；

(c) solid wall surface boundary condition: wall is set for without slip boundary condition；For wall thermal boundary condition, choose fixed temperature 300K when choosing different Abrasive Particle Size, process velocity, volume fraction, when carrying out different temperatures emulation, choose 290K, 300K, 310K, 320K and be simulated；

(3) division of model meshes: the geometric model according to atomizer, because its shape is more complicated, choose tetrahedral grid division more reasonable, division methods is fairly simple, processed by piecemeal, with tetrahedral grid the passage after piecemeal divided and grid density degree is set one by one, thus reaching to control lattice number and mesh quality purpose；

(4) simulation analysis: by atomizer being carried out the foundation of physical model and geometric model, after go forward side by side line entry boundary condition, export boundary condition and wall boundary condition are arranged, by grid division, simulation analysis can be carried out；First, carry out convergence to judge；During overall model sets, time type selecting transient type, continuous phase adopts k-epsilon turbulence model, carries out in the arranging of discrete phase following calculation according to the size of atomizer model, and step-length is 0.001mm, and maximum step number is 500 steps.Through 275 iteration, namely reach convergence.

Simulation analysis specifically includes following:

The analysis of (a) different-grain diameter downforce field: in the setting of initial condition, be respectively adopted initial velocity 80m/s, processing temperature 300K, volume fraction are 10% be set, choose the grain diameter in four kinds of meso-scales to be 200 μm, 400 μm, 600 μm, 800 μm and carry out analogue simulation, obtain the simulation result image of coupling of multiple physics field under four kinds of different-grain diameters；

The analysis in temperature field under (b) different-grain diameter: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the temperature field in the grinding process of workpiece.

The analysis of (c) different-grain diameter lower density field: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the density field in the grinding process of workpiece.

The analysis of velocity field under (d) different-grain diameter: same parameter is set choosing identical simulation, carry out the sunykatuib analysis of discrete phase, in initialized setting, to in XOYZ coordinate, only it is provided with the speed parameter 80m/s of X-direction, by obtaining the distributed image of velocity field after abrasive particle grinding work piece after simulating.

The analysis of Turbulent Kinetic under (e) different-grain diameter: after carrying out the arranging of same initial condition, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece, find to start along with abrasive particle initially enters atomizer, the Turbulent Kinetic of whole macropore cavity is minimum, and along with abrasive particle progress into endoporus place time, in crossing, Turbulent Kinetic start increase, reach maximum at aperture inwall place, weaken to some extent in aperture exit.

Particle track analysis under (f) different-grain diameter: after carrying out the arranging of initial condition equally, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece.

(5) machined parameters is to the research seeing state simulation that is situated between: that chooses 500 μm of dissipation particle granules of Abrasive Particle Size carries out analogue simulation, analyze in the different machining parameters impact on coupling of multiple physics field, its impact analysis to experiment processing is probed into, thus providing theoretical direction for experiment processing by theoretical modeling.

(a) variable concentrations impact on abrasive machining: first probe into the different abrasive concentration impact on abrasive Flow Machining, we choose the DPD granule of 500 as the lapping liquid granule simulated, the volume fraction choosing different abrasive material is analyzed, because its maximum abrasive concentration not can exceed that 10%-12%, therefore selecting four concentration variablees is 2%, 4%, 6% and 8% as the volume fraction emulated, and observes its impact on pressure field and Turbulent Kinetic.

(b) processing temperature impact on granule part during grinding: probe into the different processing temperature impact on abrasive Flow Machining, choose different processing temperature to be analyzed, according to processing environment on the spot, and Processing Surrounding Temperature change round the clock, choose 290K, 300K, 310K, 320K processing temperature as analogue simulation, observe its impact on pressure field and Turbulent Kinetic by changing processing temperature.First carrying out the analysis of dynamic pressure, the parameter that arranges chosen be volume fraction ratio 10%, Abrasive Particle Size is still 500 μm of experiment Analysis.

(c) process velocity impact on granule part during grinding: according to above analysis, abrasive Flow Machining all can be produced impact by processing temperature and abrasive concentration, analyze the process velocity impact on it, first the setting of parameter is carried out, arrange Abrasive Particle Size be 500 μm, abrasive concentration be 10%, processing temperature select 300K, friction speed parameter is 40m/s, 60m/s, 80m/s and 100m/s, and other parameter constant emulates, and observes its impact on dynamic pressure and Turbulent Kinetic.

This beneficial effect of the invention is in that: first the present invention has carried out the grasp of discrete phase granule and the understanding of volume fraction, the study of discrete phase solution procedure, the granule equation of motion, then have chosen atomizer workpiece and carries out three-dimensional mapping and carried out network analysis；By process analysis to abrasive Flow Machining workpiece in meso-scale, first have chosen dissipation particle granules particle diameter under different Jie's sight state, it it is 200 μm including Abrasive Particle Size, 400 μm, 600 μm, four kinds of grain diameters of 800 μm, by the discrete phase analysis mode to four kinds of particle diameters, we can obtain temperature field under four kinds of particle diameters, velocity field, pressure field, density field, the different distributions of Turbulent Kinetic and data, pass through analogue simulation, grain diameter is sized to have influence on the distribution of coupling of multiple physics field, the little deburring that can improve aperture crossing of grain diameter, rounding ability, and then the surface roughness within raising spray orifice, promote atomization ability, the impact that work pieces process simulation is produced by the dissipation particle granules in meso-scale is described；Again have chosen dissipation particle granules that Abrasive Particle Size is 500 μm of granules as object of study, by changing its concentration, temperature, speed, granule simulation form under Jie's sight state under different parameters can be obtained, by observing the distribution of pressure field, velocity field, Turbulent Kinetic etc., the impact on processing of the difference of parameter is described, wherein concentration is more big, temperature selects that 310K, speed are more big has appreciable impact to ground effect, it is possible to increase machining accuracy.Processed by the analogue simulation in the present invention, particles effect abrasive Flow Machining under Jie's sight state is provided reference, for providing theories integration in the actual production course of processing, compensate for the deficiency studying granule grinding under both macro and micro state, the perfect theory of granule grinding work piece.

Accompanying drawing explanation

Fig. 1 is the granule atomic group grinding work piece schematic diagram in background technology.

Fig. 2 is the atomizer three-dimensional entity model in the embodiment of the present invention.

Fig. 3 is the atomizer passage geometric model in the embodiment of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described, in order to be better understood from the present invention.

Embodiment

Discrete Phase Model granule and volume fraction set:

(1) granule in turbulence model:

Particle turbulent dispersion accounts for its impact by Stochastic Separated Flow Model and chain of particle model, and in two kinds of models, and as to the generation of continuous phase turbulent flow and dissipation, it is not directly affected by granule.As Stochastic Separated Flow Model, for the impact on particle trajectories of the instantaneous turbulent velocity, commonly used random method considers；And " on average " track determined by statistical average, then followed the tracks of by chain of particle model, and in particle swarm, particle phase volume fraction is assumed general with gaussian probability distribution function (PDF).

(2) volume fraction of granular model:

In Discrete Phase Model, it is assumed that second-phase (dispersion phase) generally leaner, so consider granule and intergranular volume fraction, interact the impact on continuous phase.After making this hypothesis, the volume fraction of dispersion phase is certainly less than 10-20%, and granular mass carries then more than 10-12%, then and the flowing of continuous phase etc./less than the mass flowrate of dispersion phase.

(3) particle in continuous phase simulation:

There are entrance and the export boundary condition relevant issues of definite definition, stable state Discrete Phase Model is more applicable, for the particle issues inapplicable that indefinite duration in continuous phase suspends, unstable state granule Discrete Phase Model generally can be applied for processing the particle process (such as blender, fluid bed) under closed system.

Discrete Phase Model solution procedure:

In common Discrete Phase Model, it is necessary first to the initial position of definitions particles, initial velocity, particle size and granule (group) temperature；Secondly according to practical physical attribute definition, by using the track initializing granule and heat transfer/matter to calculate, the determination of granule initial condition is carried out.

When granule is through fluid motion, quality/heat transmission and various equilibrant that particle trajectories and mass transfer amount, heat output are usually fluid matasomatism convection current radiation on granule and cause calculate, and its particle trajectories and corresponding mass transfer/heat are exported by image conversion interface or text interface and calculates.

(1) it is predicted the distribution of discrete phase by (non-coupled method) in fixing flow field；

(2) by considering that the flow (Coupling Between Phases method) of continuous phase is investigated distribution of particles by discrete phase.

In Coupling Between Phases calculates, there is impact in the flow field of continuous phase by the existence of discrete phase, otherwise, the flow field of continuous phase also can affect the distribution of discrete phase.By interleaved computation continuous phase and discrete phase, terminate after biphase result of calculation reaches convergence.

The granule equation of motion:

(1) dynamic balance of granule

Solving of discrete phase granule (bubble or drop) track is the granule active force differential equation by under integration Laplace coordinate system, form (x direction) under cartesian coordinate system, the force balance equation (Particle Inertia=act on the various power on granule) of granule is:

$\frac{{\mathrm{du}}_p}{dt}=F_D(u-u_p)+\frac{g_x({\mathrm{\ρ}}_p-\mathrm{\ρ})}{{\mathrm{\ρ}}_p}+F_x---\left(1\right)$

Wherein F_D(u-u_p) for the unit mass drag force of granule, wherein

$F_D=\frac{18u}{{\mathrm{\ρ}}_p{d}_p^2}\frac{C_D{R}_e}{24}---\left(2\right)$

Wherein u is fluid phase velocity, u_pFor particle speed, μ is fluid kinematic viscosity, and ρ is fluid density, ρ_pFor grain density (skeletal density), d_pFor particle diameter, Re is relative Reynolds number (particle Reynolds number), and it is defined as:

$\mathrm{Re}\≡\frac{{\mathrm{\ρd}}_p\left|u_p-u\right|}{\mathrm{\μ}}---\left(3\right)$

Drag coefficient C_DFollowing expression formula can be adopted:

$C_D=a_1+\frac{a_2}{\mathrm{Re}}+\frac{a_2}{\mathrm{Re}}---\left(4\right)$

For spheroidal particle, a in certain reynolds number range, in above formula₁,a₂,a₃For constant.

C_DMay be used without following expression formula:

$C_D=\frac{24}{\mathrm{Re}}(1+b_1{\mathrm{Re}}^{b_2})+\frac{b_3\mathrm{Re}}{b_4+\mathrm{Re}}---\left(5\right)$

Wherein:

b₁=exp (2.3288-6.4581+2.4486 φ²)

b₂=0.0964+0.5565 φ

b₃=exp (4.905-13.8944 φ+18.4222 φ²-10.2599φ³)

b₄=exp (1.4681+12.2584 φ-20.7322 φ²+15.8855φ³)(6)

The definition of form factor φ is as follows:

$\mathrm{\φ}=\frac{s}{S}---\left(7\right)$

Wherein s is the surface area that actual granule has the spheroidal particle of same volume, and S is the surface area of actual granule.

For the granule of meso-scale, Stokes drag force formula is applicable.In this case, F_DIt is defined as:

$F_D=\frac{18\mathrm{\μ}}{d_p^2{\mathrm{\ρ}}_p{C}_c}---\left(8\right)$

Coefficient C in above formula_cCunningham for Stokes drag force formula revises (correction considering the particle wall face velocity sliding of mechanics of rare fied gas), and its computing formula is:

$C_c=1+\frac{2\mathrm{\λ}}{d_p}(1.257+0.4e^{-(1.1dp/2\mathrm{\λ}})---\left(9\right)$

Wherein λ is the mean free path of gas molecule.

The form of this drag force formula is similar to the corresponding expression formula (4) of spheroidal particle, but contains part correction to adapt to the flowing that granule Mach number is more than 0.4 or particle Reynolds number is more than 20.For relating to the unsteady state flow movable model that discrete phase drop splits, it is possible to use dynamic drag force formula model.

(2) impact of gravity is considered

Equation 1 comprises the factor of gravity, but in the default mode, acceleration of gravity is zero.If considering the impact of gravity, the size and Orientation that must carry out acceleration of gravity in OperatingConditions panel sets.

(3) other active force

In other active force, most important one is additional tension stress, and it is the additional forces caused owing to make granule surrounding fluid accelerate, and its expression formula is:

$F_x=\frac{1}{2}\frac{\mathrm{\ρ}}{{\mathrm{\ρ}}_p}\frac{d}{dt}(u-u_p)---\left(10\right)$

As ρ > ρ_pTime, additional tension stress can not be ignored.The additional forces that the FPG existed in flow field causes is:

$F_x=\left(\frac{\mathrm{\ρ}}{{\mathrm{\ρ}}_p}\right)u_p\frac{\∂u}{\∂x}---\left(11\right)$

Lapping liquid granule when meso-scale in the present embodiment and the method for numerical simulation of workpiece grinding, specifically comprise the following steps that

(1) computation model is set up and initial condition:

Non-rectilinear pipe part is widely used in the fields such as Aero-Space, automobile making, Making mold, high cleanliness part, textile machine, diesel engine manufacture, hydraulic part manufacture.The present invention selects in diesel fuel system important composition parts atomizer as object of study, and atomizer effect is that bavin Water Oil Or Gas enters cylinder through atomizer endoporus, by high pressure fuel injector, makes oil atomization, burns through plug ignition, starts electromotor.Therefore atomizer aperture processing request is very high, its required precision directly affects engine spray atomization and performance, and simultaneously the economy of the sealing of atomizer, service life and electromotor and discharge index etc. are also all subject to the impact of atomizer crudy.

The embodiment of the present invention have chosen Diesel engine atomizer part, access road macropore port diameter is 4, the tapered shape of spray nozzle front end, is uniformly distributed six spray orifices, hole diameter is 0.16mm, carrying out three-dimensional drawing by CATIA, its three-dimensional entity model result is illustrated in fig. 2 shown below, to the part body portion being made without simulation, simplify, retain macropore inside and aperture nozzle flow channel, obtain its passage geometric model, as shown in Figure 3.

By setting up atomizer three-dimensional entity model and geometric model, laying the foundation for carrying out abrasive particle grinding analysis, therefore its model need hold water, the runner situation within atomizer can be represented, mapped by three-dimensional software, after structure distribution is reasonable, then carry out FLUENT analogue simulation analysis.

(2) setting of computation model boundary condition, specifically includes:

A () entrance boundary condition: entrance boundary condition refers to the flow variables determining porch, it includes speed entrance boundary condition, pressure entrance boundary condition and quality entrance boundary condition.Its medium velocity entrance boundary condition is the scalar that flowing velocity is relevant with the flow properties of flowing entrance.And be Discrete Phase Model according to selected model, therefore need the situation setting continuous phase with discrete phase.

Continuous phase: atomizer passage inlet port adopts speed condition for import, sets now import department's abrasive Flow and as turbulence state, selects k-epsilon (2eqn) model in Model, select Realizable, confirm in k-epsilonModel.Energy model is chosen EnergyEquation activation energy equation.

Discrete phase: the granule selecting analogue simulation is granule, its concentration (i.e. volume fraction) is more big, so granule is more many with the particle of wall grinding, namely ground effect is more good, the ablation of inner surface is obvious, according in Discrete Phase Model, assuming that second-phase (discrete phase) generally leaner, after making this hypothesis, the volume fraction of discrete phase is certainly less than 10%-20%, granular mass carries then more than 10%-12%, so flowing of continuous phase etc./less than the mass flowrate of dispersion phase, therefore different-grain diameter is carried out, different temperatures, processing it is simulated when friction speed, the concentration chosen is 10%, when carrying out variable concentrations simulation, choose 2% respectively, 4%, 6% and 8% is relatively reasonable.

(b) export boundary condition:

Export boundary condition comprises pressure export boundary condition, quality export boundary condition, and pressure export boundary condition needs to formulate gauge pressure at outlet boundary, and choosing of gauge pressure value is only applicable to subsonic flow；And quality export boundary condition is solving before flow field problem and the speed of unclear flowing outlet and pressure, and if simulate be compressible flow or include pressure export, it is impossible to use.By abrasive Flow grinding atomizer physical condition it can be seen that come round in the port of export and the external world, therefore it is set as free export.

(c) solid wall surface boundary condition:

In abrasive Flow Machining process, the flowing grinding work piece wall making lapping liquid carries out the process of grinding, namely abrasive material is viscous fluid, and for VISCOUS FLOW, can arrange wall is without slip boundary condition, during when wall for translation or rotary motion, it is also possible to specify wall tangential speed component, provide wall shear stress, thus simulating wall slippage.And in the experiment of actual abrasive Flow, wall does not translate or rotates, therefore is set as without slip boundary.For wall thermal boundary condition, choose fixed temperature 300K when choosing different Abrasive Particle Size, process velocity, volume fraction, when carrying out different temperatures emulation, choose 290K, 300K, 310K, 320K and be simulated.

(3) division of model meshes:

The approach of FLUENT grid division has two kinds, and a kind of is carry out stress and strain model by the FLUENT Meshing function carried: another kind of then be completed moulding work by other CAD software, then imports in other Grid Generation Softwares such as ICEMCFD generation grid.

The grid that ICEMCFD generates is broadly divided into tetrahedral grid, hexahedral mesh, prismatic mesh, O-Grid grid etc..Tetrahedral grid can be good at the geometric model that laminating is complicated, generates simple；Hexahedral mesh mesh quality is high, it is necessary to the number of grid of generation is relatively fewer, is suitable for mesh quality is required higher model, but the process of generation is complicated；Prismatic mesh is suitable for thin-walled geometric model；Grid grid is suitable for circle or arc model.

Geometric model according to atomizer, because its shape is more complicated, choose tetrahedral grid division more reasonable, division methods is fairly simple, processed by piecemeal, with tetrahedral grid the passage after piecemeal divided and grid density degree is set one by one, thus reaching to control lattice number and mesh quality purpose.By to mesh quality Index for examination: quality (is generally higher than 0.3), minimum angles (is generally higher than 18 degree), determinant (being typically larger than 0.3) etc. carries out mesh quality inspection.By testing, being absent from negative volume, mesh quality is reliable.

(4) simulation analysis: by atomizer being carried out the foundation of physical model and geometric model, after go forward side by side line entry boundary condition, export boundary condition and wall boundary condition are arranged, by grid division, simulation analysis can be carried out.The grinding now carrying out meso-scale endoparticle and workpiece is simulated, and by analyzing the analog result of different coupled field, obtains the essence of grinding in meso-scale, in order to put forward work theoretical direction for experiment processing.

First, carry out convergence to judge.During overall model sets, time type selecting transient type, continuous phase adopts k-epsilon turbulence model, size according to atomizer model carries out in the arranging of discrete phase following calculation, step-length (StepLength) is 0.001mm, and maximum step number (Max.NumberofSteps) is 500 steps.Through 275 iteration, namely reach convergence.

Simulation analysis specifically includes following:

The analysis of (a) different-grain diameter downforce field: in the setting of initial condition, be respectively adopted initial velocity 80m/s, processing temperature 300K, volume fraction are 10% be set, choose the grain diameter in four kinds of meso-scales to be 200 μm, 400 μm, 600 μm, 800 μm and carry out analogue simulation, obtain the simulation result image of coupling of multiple physics field under four kinds of different-grain diameters.After being analyzed by grinding, can be seen that particle starts to flow into atomizer from entrance from dynamic pressure cloud atlas, after the grinding of atomizer workpiece, flow out from six little mouths of pipe.And dynamic pressure is minimum from entrance beginning, after entering atomizer, pressure does not significantly change, and abrasive particle is six crossings, dynamic pressure increases, illustrating that the grain motion of crossing is fierce, working (machining) efficiency is higher, when entering in aperture, dynamic pressure increases further, it is now fierce at aperture endoporus grain motion to illustrate, working (machining) efficiency is the highest, improves the precision of workpiece.Abrasive particle grinding atomizer is carried out further data analysis, because the change of dynamic pressure is comparatively obvious at the distributed image within crossing and aperture, therefore from crossing, aperture entrance, aperture stage casing and aperture exit be divided into four data fields to be analyzed, it is divided into data 1 district, data 2 district, data 3 district, data 4 district, the dynamic pressure of abrasive particle grinding work piece changes checking analysis below that carry out in data, and the dynamic pressure numeric distribution table listing four data areas is as shown in table 1 below.

Atomizer dynamic pressure data distribution table under table 1 different-grain diameter

The data of analytical table 1, the dynamic pressure change of abrasive particle grinding work piece can be probed into: the dynamic pressure change that (1) is first analyzed under same Abrasive Particle Size data, by data in table it can be seen that data 4 district > data 3 district > data 2 district > data 1 district, namely along with abrasive particle progresses into workpiece, dynamic pressure in crossing starts to increase, illustrate that now there is grinding trend crossing by abrasive particle, namely to hole rounding；And at aperture entrance place, stage casing, exit dynamic pressure continue to increase, now grain motion is comparatively fierce, starts aperture inwall is ground polishing；(2) different abrasive particle dynamic pressure situation is secondly analyzed, it can be seen from the table, along with Abrasive Particle Size is gradually increased, four data field dynamic pressure all present decline trend, it is because abrasive particle from common inlet pressure, owing to abrasive particle increases, contact surface area increases therewith, when grain weight increases, abrasive particle flow rate diminishes immediately, so dynamic pressure is also gradually reduced, illustrate that the effect that aperture carries out skin processing weakens gradually along with abrasive particle increases.

The analysis in temperature field under (b) different-grain diameter: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the temperature field in the grinding process of workpiece.Therefrom it is evident that temperature field presents in atomizer is significantly uniformly distributed, higher near the temperature value of wall, the temperature of centre bore is relatively low, this is because abrasive particle and wall collide, and then the raw heat of grinding, make temperature slightly promote.And totally see, temperature keeps a steady state value, and this is relevant with the temperature of our initial setting up, in whole process, it does not have significantly change occurs, and keeps stationary temperature, demonstrates the correctness that model is chosen.After the change of temperature field image of observation abrasive particle grinding atomizer, still analyse in depth from data aspect, whole process we be still analyzed from three data areas, choose entrance equally, crossing, three mouths of pipe of outlet are that data field is analyzed, and data show to be all 300K, namely the temperature after abrasive particle grinding is not changed in, still identical with the temperature arranged, this is because whole simulation process iterations is less, the heat that whole grinding process produces is ignored.

The analysis of (c) different-grain diameter lower density field: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the density field in the grinding process of workpiece.Whole process also keeps a constant value, but the density field of particle presents different forms, along with Abrasive Particle Size changes, density field presents sparse state, this and abrasive grain diameter become big, spacing between particle becomes relevant greatly, observe entrance, atomizer internal cavity, crossing, the change in exit, can find, each position density field presents rarefaction state equally, and research grinding process is had important meaning by the abrasive grain density studying abrasive particle inner hole grinding place, abrasive particle is more little, density is more big, so just can be relatively more by the abrasive particle of endoporus inwall, to research abrasive particle to non-straight spool deburring, rounding and enhancing surface roughness have reality impact.Equally abrasive particle grinding being carried out data analysis, only selecting cavity and endoporus is survey region, and its data are 1.11V, and relation not obvious with the change of size of abrasive particle, the particle diameter that this and institute are chosen gets too close to relevant.

The analysis of velocity field under (d) different-grain diameter: same parameter is set choosing identical simulation, carry out the sunykatuib analysis of discrete phase, in initialized setting, to in XOYZ coordinate, only it is provided with the speed parameter 80m/s of X-direction, by obtaining the distributed image of velocity field after abrasive particle grinding work piece after simulating.Can obtaining abrasive particle from porch, to entering inside cavity, whole velocity field keeps a steady state value constant, is because just individual cavity space region big, it does not have the loss of speed；And start along with abrasive particle enters 6 apertures, speed presents the trend of increase, start to outlet from aperture, become larger, this is because along with abrasive particle progresses into aperture endoporus, area of space diameter of section diminishes, when abrasive particle flow is constant, speed increases therewith, and grinding capacity strengthens, the strongest in crossing and aperture inwall deburring and rounding ability, working (machining) efficiency is high.After the emulating image of observation abrasive particle grinding, it is carried out the analysis of data aspect, change according to speed flowing, choose five data areas to be analyzed, choose respectively and be divided into same three regions inside the inside abrasive particle rate areas of inlet chamber, region, abrasive particle grinding aperture crossing, aperture, being decided to be: data 1 district, data 2 district, data 3 district, data 4 district and data 5 district, the dynamic pressure numeric distribution table listing five data areas is as shown in table 2 below.

Atomizer velocity field data distribution table under table 2 variable grain particle diameter

It is analyzed by table 2, (1) when Abrasive Particle Size remains unchanged, the speed of each data area constantly increases, i.e. data 5 district > data 4 district > data 3 district > data 2 district > data 1 district, illustrate along with in abrasive particle whole process from the inlet to the outlet, all very fierce at crossing, aperture inwall wall grain motion, namely grinding capacity is strengthened, and carries out wall polishing ability and strengthens；(2) along with Abrasive Particle Size increases, the rate value of each data area tapers into, and grain motion severity is gradually lowered, and skin processing ability weakens gradually.These results suggest that and choose the less abrasive machining effect of particle diameter preferably, grinding capacity is the strongest.

The analysis of Turbulent Kinetic under (e) different-grain diameter

After carrying out the arranging of same initial condition, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece, find to start along with abrasive particle initially enters atomizer, the Turbulent Kinetic of whole macropore cavity is minimum, and along with abrasive particle progress into endoporus place time, in crossing, Turbulent Kinetic start increase, reach maximum at aperture inwall place, weaken to some extent in aperture exit.After observing analog image, the obvious region of data is selected to be analyzed, because the change of dynamic pressure is comparatively obvious at the distributed image within crossing and aperture, therefore from crossing, aperture entrance, aperture stage casing and aperture exit be divided into four data fields to be analyzed, it is divided into data 1 district, data 2 district, data 3 district, data 4 district, the Turbulent Kinetic numeric distribution table listing four data areas is as shown in table 3 below.

Atomizer Turbulent Kinetic data distribution table under table 3 different-grain diameter

Being analyzed by his-and-hers watches 3, when (1) carries out grinding under same Abrasive Particle Size, Turbulent Kinetic is minimum in macroporous cavity body, along with abrasive particle enters aperture, strengthen in aperture crossing Turbulent Kinetic, reach maximum at aperture inwall, once more reduce at little hole exits, i.e. data 3 district > data 2 district > data 4 district > data 1 district, illustrating along with processing deeply, abrasive particle is relatively strong in crossing and aperture inwall motor capacity, and grinding capacity increases therewith, and exit energy dropoff, grinding capacity reduces；(2) along with Abrasive Particle Size increases, the Turbulent Kinetic of each data field weakens, and namely Abrasive Particle Size is more big, and Turbulent Kinetic is more little, so choosing the abrasive particle that particle diameter is less, it is possible to strengthens tubulence energy intensity, and then increases grinding capacity.

Particle track analysis under (f) different-grain diameter:

After carrying out the arranging of initial condition equally, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece, find out abrasive Flow radius vector mark under different-grain diameter, according to particle arrow, abrasive particle initially enters from macropore entrance, through macropore die cavity, at aperture, crossing proceeds to, and then inside entrance aperture, flow out from little hole exits again, whole glide path meets the situation of actual processing, illustrate that abrasive particle can to big wall surface of the hole when flowing through inside workpiece, aperture crossing and inwall produce collision, and then grinding, reach the deburring to crossing, the purpose of rounding and surface finishing.Actual production processing is played preanalysis and is estimated by research particle track, it is possible to controls the path of abrasive machining, and then realizes high efficient grinding, improves skin processing ability.

(5) machined parameters is to the research seeing state simulation that is situated between:

By simulation analysis above, can obtain grain diameter is 200 μm, 400 μm, 600 μm, the distribution situation of the coupling of multiple physics field of 800 μm of particles, by the impact on different fields of the analysing particulates particle diameter, illustrate in the impact on abrasive machining of the meso-scale endoparticle particle diameter, and in actual production is processed, abrasive concentration, abrasive Flow production and processing all can be produced impact by processing temperature and process velocity etc., therefore we choose grain diameter be 500 μm of dissipation particle granules carry out analogue simulation, analyze in the different machining parameters impact on coupling of multiple physics field, its impact analysis to experiment processing is probed into by theoretical modeling, thus providing theoretical direction for experiment processing.

The impact on abrasive machining of (a) variable concentrations:

First the different abrasive concentration impact on abrasive Flow Machining is probed into, we choose DPD granule that grain diameter the is 500 μm lapping liquid granule as simulation, the volume fraction choosing different abrasive material is analyzed, because its maximum abrasive concentration not can exceed that 10%-12%, therefore selecting four concentration variablees is 2%, 4%, 6% and 8% as the volume fraction emulated, and observes its impact on pressure field and Turbulent Kinetic.Starting to macropore inner chamber from entrance, dynamic pressure presents minimum state, starts entering aperture place, and dynamic pressure is changed from small to big, and dynamic pressure strengthens gradually, and namely the grinding of aperture is gradually increased by abrasive particle, and polishing effect is strengthened.Choosing macropore die cavity as data 1 district, crossing as being divided into three data fields inside data 2 district, aperture, be designated as: data 3 district, data 4 district and data 5 district, the Turbulent Kinetic numeric distribution table listing four data areas is as shown in table 4 below.

Atomizer dynamic pressure data distribution table under the different abrasive concentration of table 4

The data of analytical table 4, dynamic pressure change under different abrasive concentration can be obtained: the dynamic pressure change that (1) is first analyzed under same Abrasive Particle Size, by data in table it can be seen that data 5 district > data 4 district > data 3 district > data 2 district > data 1 district, namely along with abrasive particle progresses into workpiece, minimum in the dynamic pressure force value of macropore die cavity, dynamic pressure in crossing starts to increase, and illustrates that now there is grinding trend crossing by abrasive particle, namely to hole rounding；And at aperture entrance place, stage casing, exit dynamic pressure continue to increase, now grain motion is comparatively fierce, starts aperture inwall is ground polishing；(2) dynamic pressure situation under different abrasive concentration is secondly analyzed, it can be seen from the table, along with Abrasive Particle Size is gradually increased, five data field dynamic pressure all present increasing trend, this is owing to abrasive concentration increases, abrasive material and work piece inner surface contact surface area increase therewith, and the grinding with inwall wall also strengthens, thus improving the effect to aperture skin processing.

Because the change of energy can illustrate the significance of processing effect, therefore the change of Turbulent Kinetic is as the emphasis analyzed, first carry out same parameter to arrange, choose variable concentrations proportion grading, along with abrasive material enters atomizer, the Turbulent Kinetic of porch is the strongest, start therewith to weaken, when entering macropore front end, Turbulent Kinetic reaches minimum, this is because in whole flow process, along with the abrasive material grinding to wall, energy reduces, the merit of grinding force and interior energy it is converted into by initial kinetic energy, and atomizer inwall surrounding starts to weaken at first, center is weakened subsequently, become parabolic shape form；Starting entering aperture place, due to the instantaneous reduction of cross section, Turbulent Kinetic increases, and the abrasive material entering aperture proceeds by the acting of grinding wall, and Turbulent Kinetic starts again to weaken.

According to above analysis, carry out the process in data and numerical analysis, because macropore and aperture energy each change, therefore individually it is analyzed, first chooses macropore back segment and carry out three data partitions, be set to entrance as data 1 district, posterior segment data 2 district, stage casing is data 3 districts；Aperture crossing is that in data 1 district, aperture, stage casing is data 2 district, little hole exits is data 3 districts, is listed as follows:

Workpiece Turbulent Kinetic data distribution table under the different abrasive concentration of table 5

Analytical table 5 is it can be seen that (1) same abrasive concentration, data 1 district in region, large aperture > data 2 district > data 3 district, and the energy loss in each district is fast, decline 3 to 4 levels；In orifice region, for abrasive concentration 6%, being initially 4.24, during to aperture stage casing, drop to 2.12, drop to 0.708 to exporting out, whole decline Process Energy loss is also a lot, illustrates that energy is converted into the merit of grinding work piece also many.(2) along with abrasive concentration constantly increases, the Turbulent Kinetic of each data field is increase trend, and the magnitude of rising is little, illustrate that abrasive concentration difference can affect the energy variation of Turbulent Kinetic, select suitably to increase abrasive concentration, it is possible to promote Turbulent Kinetic energy, thus increasing ground effect.

Because abrasive concentration is different, the change of density field is more apparent, and the analysis carrying out density field is particularly important.Therefrom find out that the density started from entrance is relatively larger, along with simulation starts, abrasive material progresses into aperture, macropore enter aperture infall, the density step-down of peripheral abrasive concentration, more more low toward macropore marginal density, this illustrates in simulating cutting process, the grinding of wall can be weakened by abrasive particle, starts until entering aperture, and abrasive grain density also comparatively reduces.

Carry out numerical analysis, because the density that abrasive material enters is all 1.1V all mutually, still choose macropore enter aperture periphery be analyzed area, select macropore leading portion and tip portion region to be analyzed area and aperture portion is analyzed area, therefore set macroperforation as three data fields, data 1 district, data 2 district and data 3 district it is designated as from macropore center to surrounding；Aperture portion is also 3 data fields, and crossing is designated as data 1 district, aperture stage casing is designated as data 2 district, aperture exit is designated as data 3 district, is listed as follows,

Workpiece density field data distribution table under the different abrasive concentration of table 6

It is analyzed by table 6, (1) in same wear particle concentration situation, data 1 district of macroporous regions > data 2 district > data 3 district, illustrate that abrasive material concentrates on region, macropore centre, the abrasive material of Regional Dispersion is less towards periphery, the grinding force of macropore inwall is weakened, in orifice region, data 1 district > data 2 district > data 3 district, when illustrating to enter aperture endoporus, aperture crossing abrasive density is big, certain ablation is played for rounding, after entering aperture inwall, abrasive grain density decreases, and ground effect weakens.Above analytic explanation to reach the ablation of atomizer, it is necessary to increases pressure, makes abrasive density dispersed, reach ground effect.

(2) difference according to abrasive concentration, abrasive material tamped density also changes therewith, along with abrasive concentration strengthens, each data area density strengthens, with cavity and aperture contact internal walls increase in density, illustrate that increasing concentration can improve abrasive material degree of scatter, and then is conducive to ground effect to strengthen.

The impact on granule part during grinding of (b) processing temperature

Probe into the different processing temperature impact on abrasive Flow Machining, choose different processing temperature to be analyzed, according to processing environment on the spot, and Processing Surrounding Temperature change round the clock, choose 290K, 300K, 310K, 320K (i.e. room temperature 17 DEG C, 27 DEG C, 37 DEG C, 47 DEG C) processing temperature as analogue simulation, observe its impact on pressure field and Turbulent Kinetic by changing processing temperature.First carrying out the analysis of dynamic pressure, the parameter that arranges chosen be volume fraction ratio 10%, Abrasive Particle Size is still 500 experiment Analysis, by simulating.Under different processing temperatures, dynamic pressure emulating image basic simlarity, is all show minimum dynamic pressure in macroporous cavity body, starts to increase in the crossing's dynamic pressure entering aperture, and along with entering aperture inwall, dynamic pressure continues to increase, and in exit, dynamic pressure is uniform.

Carrying out the analysis in data equally, choosing macroporous regions be data 1 district, crossing is data 2 districts, is divided into 3 data fields inside aperture, and namely small hole center to be data 3 district, small hole center extension be data 4 district, little wall surface of the hole are data 5 districts, are listed as follows,

Workpiece dynamic pressure data distribution table under the different processing temperature of table 7

According to table 7, carry out data analysis, (1) at the same temperature, dynamic pressure is from minima 0.54, through processing, maintaining about 1.60 in crossing, dynamic pressure adds 1 magnitude, illustrate that the cross-sectional area of crossing reduces the numerical value affecting dynamic pressure, along with entering inside aperture, aperture entrance pressure, from about 2.68, increases to about 3.7 when aperture stage casing, it is 4.8 to the maximum in aperture wall pressure, illustrates that now aperture place grinding strengthens；(2) when constantly rising along with processing temperature, dynamic pressure reduces therewith, explanation processing temperature increases, abrasive material viscosity strengthens, and dynamic pressure reduces, the effect of impact processing, in data 1 district, the range of decrease is minimum, data 5 district is relatively big, illustrates that aperture internal dynamic pressure impact is relatively big, selects suitable processing temperature that abrasive material viscoelasticity and processing dynamic pressure are had big impact.Under different processing temperatures, Turbulent Kinetic is maximum in porch, and along with processing, Turbulent Kinetic diminishes, and at aperture entrance place, Turbulent Kinetic increases, and starts again to weaken at aperture inwall, again reduces to outlet.

Choosing macropore entrance is that data 1 district, macropore center section part are divided into data 2 district, macropore front end to be data 3 districts, and aperture is also classified into 3 regions, and aperture entrance is data 1 district, aperture stage casing be data 2 district, aperture exit is data 3 districts, and data list is as follows,

Workpiece Turbulent Kinetic data distribution table under the different processing temperature of table 8

It can be seen that (1) same processing temperature, data 1 district in region, large aperture from table > data 2 district > data 3 district, and the energy loss in each district is fast, decline 3 to 4 magnitudes；In orifice region, for processing temperature 290K, being initially 5.38, during to aperture stage casing, drop to 2.69, drop to 0.896 to exporting out, whole decline Process Energy loss is also a lot, illustrates that energy is converted into the merit of grinding work piece also many.(2) along with processing temperature constantly increases, from 290K to 310K, Turbulent Kinetic raises along with temperature, and numerical value is gradually increased, and starts again afterwards to reduce at 320K temperature, illustrate that temperature is under 310K, namely, at room temperature 37 DEG C, turbulent flow is dynamic to be reached maximum, and processing temperature now is relatively reasonable, Turbulent Kinetic numerical value is best, thus improving ground effect.Along with processing temperature increases, the color of analog image gradually becomes shallower as, and namely temperature be increasing trend, consistent with set temperature parameter, it was demonstrated that the correctness simulated.

The process velocity impact on granule part during grinding:

According to above analysis, abrasive Flow Machining all can be produced impact by processing temperature and abrasive concentration, we analyze the process velocity impact on it, first the setting of parameter is carried out, arrange Abrasive Particle Size be 500 μm, abrasive concentration be 10%, processing temperature select 300K, friction speed parameter is 40m/s, 60m/s, 80m/s and 100m/s, and other parameter constant emulates, and observes its impact on dynamic pressure and Turbulent Kinetic.Under different process velocities, dynamic pressure cloud atlas after abrasive Flow Machining is similar, it is all minimum at entrance and inside cavity dynamic pressure, increase in aperture crossing dynamic pressure, along with abrasive material aperture inwall starts grinding, dynamic pressure is gradually increased, and the dynamic pressure at small hole center place is relatively bigger than the dynamic pressure of aperture inwall, and process velocity described above can affect the distribution of dynamic pressure.

Being analyzed by images above, we carry out the analytic explanation in data further, and the dynamic pressure choosing crossing is that in data 1 district, aperture, place is divided into three data fields, namely aperture entrance, in the middle part of aperture, little hole exits, according to view data, be listed as follows.

Workpiece dynamic pressure data distribution table under the different process velocity of table 9

By the data in table 9, can obtain: (1) is under same process velocity, along with abrasive material is from macropore porch, dynamic pressure is gradually increased, trend is significantly increased in aperture crossing (data 4 district), in aperture, dynamic pressure rate of increase strengthens, and illustrates that the grinding to aperture strengthens；(2) along with process velocity increases, dynamic pressure is increase tendency, and in aperture, Magnification is obvious equally, illustrates that increasing process velocity can improve abrasive material dynamic pressure, promotes the grinding to aperture inwall then.

Identical parameter is set, analyzing the different process velocity impact on Turbulent Kinetic, analysis mode result is as follows, along with abrasive flow, abrasive particle is minimum to the die cavity tubulence energy of macropore, when in crossing, Turbulent Kinetic increases, along with abrasive particle enters aperture, Turbulent Kinetic continues to strengthen, this illustrates, abrasive particle is maximum to the grinding force of crossing and aperture inwall, and ground effect is best.According to analog image result, choosing crossing, aperture interior inlet, middle part, outlet are data area, namely four data fields, are listed as follows.

Workpiece Turbulent Kinetic data distribution table under the different process velocity of table 10

Analytical table 10, can obtain: (1) is under same process velocity, along with abrasive material is from macropore porch, Turbulent Kinetic is minimum, being gradually increased in aperture crossing (data 1 district) Turbulent Kinetic, in aperture, Turbulent Kinetic rate of increase strengthens, illustrating that the grinding force to crossing strengthens, deburring and rounding strengthen；(2) along with process velocity increases, Turbulent Kinetic is increase tendency, illustrates that Turbulent Kinetic is strengthened along with speed increases, and then aperture inwall grinding capacity is deepened, and polishing effect is notable.

The above is the preferred embodiment of the present invention; it should be pointed out that, for those skilled in the art, under the premise without departing from the principles of the invention; can also making some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.

Claims (3)

1. the method for numerical simulation of a lapping liquid granule when meso-scale and workpiece grinding, it is characterised in that: specifically comprise the following steps that

(1) computation model is set up and initial condition: choose Diesel engine atomizer part, access road macropore port diameter is 4mm, the tapered shape of spray nozzle front end, being uniformly distributed six spray orifices, hole diameter is 0.16mm, carries out three-dimensional drawing by CATIA, to the part body portion being made without simulation, simplify, retain macropore inside and aperture nozzle flow channel, obtain its passage geometric model；By setting up atomizer three-dimensional entity model and geometric model, lay the foundation for carrying out abrasive particle grinding analysis, mapped by three-dimensional software, after structure distribution is reasonable, then carry out FLUENT analogue simulation analysis；

(2) setting of computation model boundary condition, specifically includes:

A () entrance boundary condition: entrance boundary condition refers to the flow variables determining porch, it includes speed entrance boundary condition, pressure entrance boundary condition and quality entrance boundary condition；Its medium velocity entrance boundary condition is the scalar that flowing velocity is relevant with the flow properties of flowing entrance；And be Discrete Phase Model according to selected model, therefore need the situation setting continuous phase with discrete phase；

Continuous phase: atomizer passage inlet port adopts speed condition for import, sets now import department's abrasive Flow and as turbulence state, selects k-epsilon model in Model, select Realizable, confirm in k-epsilonModel；Energy model is chosen EnergyEquation activation energy equation；

Discrete phase: being simulated processing when carrying out different-grain diameter, different temperatures, friction speed, the concentration chosen is 10%, when carrying out variable concentrations simulation, chooses 2%, 4%, 6% and 8% respectively；

(b) export boundary condition: by abrasive Flow grinding atomizer physical condition it can be seen that come round in the port of export and the external world, therefore be set as free export；

(c) solid wall surface boundary condition: wall is set for without slip boundary condition；For wall thermal boundary condition, choose fixed temperature 300K when choosing different Abrasive Particle Size, process velocity, volume fraction, when carrying out different temperatures emulation, choose 290K, 300K, 310K, 320K and be simulated；

(3) division of model meshes: the geometric model according to atomizer, because its shape is more complicated, choose tetrahedral grid division more reasonable, division methods is fairly simple, processed by piecemeal, with tetrahedral grid the passage after piecemeal divided and grid density degree is set one by one, thus reaching to control lattice number and mesh quality purpose；

(4) simulation analysis: by atomizer being carried out the foundation of physical model and geometric model, after go forward side by side line entry boundary condition, export boundary condition and wall boundary condition are arranged, by grid division, simulation analysis can be carried out；Carry out convergence to judge；During overall model sets, time type selecting transient type, continuous phase adopts k-epsilon turbulence model, carries out in the arranging of discrete phase following calculation according to the size of atomizer model, and step-length is 0.001mm, and maximum step number is 500 steps；Through 275 iteration, namely reach convergence；

(5) machined parameters is to the research seeing state simulation that is situated between: that chooses 500 dissipation particle granules carries out analogue simulation, analyze in the different machining parameters impact on coupling of multiple physics field, its impact analysis to experiment processing is probed into, thus providing theoretical direction for experiment processing by theoretical modeling.

2. the method for numerical simulation of lapping liquid granule when meso-scale according to claim 1 and workpiece grinding, it is characterised in that: described simulation analysis specifically includes following aspect:

The analysis of (a) different-grain diameter downforce field: in the setting of initial condition, be respectively adopted initial velocity 80m/s, processing temperature 300K, volume fraction are 10% be set, choose the grain diameter in four kinds of meso-scales to be 200 μm, 400 μm, 600 μm, 800 μm and carry out analogue simulation, obtain the simulation result image of coupling of multiple physics field under four kinds of different-grain diameters；

The analysis in temperature field under (b) different-grain diameter: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the temperature field in the grinding process of workpiece；

The analysis of (c) different-grain diameter lower density field: after carrying out the arranging of same initial condition, carry out the abrasive particle analysis to the density field in the grinding process of workpiece；

The analysis of velocity field under (d) different-grain diameter: same parameter is set choosing identical simulation, carry out the sunykatuib analysis of discrete phase, in initialized setting, to in XOYZ coordinate, only it is provided with the speed parameter 80m/s of X-direction, by obtaining the distributed image of velocity field after abrasive particle grinding work piece after simulating；

The analysis of Turbulent Kinetic under (e) different-grain diameter: after carrying out the arranging of same initial condition, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece, find to start along with abrasive particle initially enters atomizer, the Turbulent Kinetic of whole macropore cavity is minimum, and along with abrasive particle progress into endoporus place time, in crossing, Turbulent Kinetic start increase, reach maximum at aperture inwall place, weaken to some extent in aperture exit；

Particle track analysis under (f) different-grain diameter: after carrying out the arranging of initial condition equally, carry out abrasive particle to the Turbulent Kinetic analysis in the grinding process of workpiece.

3. the method for numerical simulation of lapping liquid granule when meso-scale according to claim 1 and workpiece grinding, it is characterised in that: the research seeing state simulation that is situated between is specifically included following aspect by described machined parameters:

(a) variable concentrations impact on abrasive machining: first probe into the different abrasive concentration impact on abrasive Flow Machining, we choose DPD granule that Abrasive Particle Size the is 500 μm lapping liquid granule as simulation, the volume fraction choosing different abrasive material is analyzed, because its maximum abrasive concentration not can exceed that 10%-12%, therefore selecting four concentration variablees is 2%, 4%, 6% and 8% as the volume fraction emulated, and observes its impact on pressure field and Turbulent Kinetic；

(b) processing temperature impact on granule part during grinding: probe into the different processing temperature impact on abrasive Flow Machining, choose different processing temperature to be analyzed, according to processing environment on the spot, and Processing Surrounding Temperature change round the clock, choose 290K, 300K, 310K, 320K processing temperature as analogue simulation, observe its impact on pressure field and Turbulent Kinetic by changing processing temperature；First carrying out the analysis of dynamic pressure, the parameter that arranges chosen be volume fraction ratio 10%, Abrasive Particle Size is still 500 μm of experiment Analysis；

(c) process velocity impact on granule part during grinding: according to above analysis, abrasive Flow Machining all can be produced impact by processing temperature and abrasive concentration, analyze the process velocity impact on it, first the setting of parameter is carried out, arrange Abrasive Particle Size be 500 μm, abrasive concentration be 10%, processing temperature select 300K, friction speed parameter is 40m/s, 60m/s, 80m/s and 100m/s, and other parameter constant emulates, and observes its impact on dynamic pressure and Turbulent Kinetic.