| A brief summary of the development of hydraulic impactor at home and abroad, andelaborated the achievements and progress in theoretical model, simulation technology,system control and performance testing. Discussed the principle of mathematical modelingfor the hydraulic system simulation, and based on the flow field numerical simulation(CFD) analysis, described the solver method for solving equations and discrete way.According to the impactor real vehicle control system, modeling validation for powercomponents and control components, obtained the approximate simulation results with thevehicle system calibration value. In accordance with the physical model of the impactsystem, build system simulation model in Amesim, and access to the dynamiccharacteristics of the movement of the piston at different operating conditions. At the sametimes, get the flow and pressure fluctuations characteristics of different chambers. Impactsimulation results with the experimental values trend consistent.Established the two-dimensional geometric model of the impact piston regional, andset boundary layer treatment in the front and back and intermediate chamber with the oilinlet junction, by continuously adjusting the chamber grid density to ensure the stability ofsolutions. Using dynamic mesh technique, the movement of the piston and the chamber oilchange coupled analysis. Obtain the fluid dynamic change, including the front chamberwith the first signal port, the middle chamber with the second signal port and the backcavity region, and get the vortex appeared location and the effect on mainstream velocity,and the oil flow rate variation crossing are analyzed in detail. On the basis of numericalsimulation, acquire different moments of the chamber wall static pressure variations. By the stress analysis of the fluid control body, the effective role of the piston wall has beenintegrated expression. Through to the analysis of the piston axis direction force, obtainedthat the chamber has a closed or open trend the stress will produce a jump. At the sametime, the results of numerical simulation of mathematical model of pressure variationcoefficient can be determined.According to the impact system, build the real vehicle detection platform andproposed a new method based on the oscillometric detection. Of different conditions of theimpact device for vehicle detection, obtained the impactor inlet flow, pressure trend;according to the principle of feedback control on nitrogen chamber, under differentconditions of flow data analysis, obtain the piston velocity, displacement and energy curve.The change trend of the pressure coefficient in the mathematical model can be obtained bythe import and export flow test values and the piston part numerical simulation results, andto provide model validation for the improvement of mathematical model. |
PDF Full Text Request