| Rail-track engineering department efficiently govern the rail damage by the rail grinding train method. Rail transport is busy, so the line maintenance "Window" is short, requiring rail grinding train quickly reach the operation area and the rail grinding train locomotive’s styling has a non-streamlined design. During the operation of the railway in the wind area, the strong wind would cause a sudden change of flow field around it, causing a large aerodynamic load, which may endanger the operational safety of the rail grinding train. This thesis based on aerodynamics and multi-body system dynamics to study the aerodynamics characteristics and operational safety of rail grinding train under strong side wind.By the analysis of the flow field around the rail grinding train and the simplification of the model, this thesis establishes a 3-D turbulence model of the rail grinding train with the help of computational fluid dynamics software FLUENT, based on the 3-D steady-incompressible N-S equation and standard k-s turbulence model. Through multiple spreadsheets, we determine the most appropriate size of the computational domain. For the situation of no wind and strong cross wind in the flow field simulation, the aerodynamics characteristics of the rail grinding train under different operating speeds and wind scale have been calculated, and the surface pressure, flow characteristics distribution and pneumatic load characteristics have also been analyzed. Besides, the impacts of operating speed and wind scale on aerodynamic loads have been studied.Based on multi-body dynamics theory, a rail grinding train dynamics model by utilizing SIMPACK software has been established. Subsequently, put the aerodynamic load on train to the dynamics model, simulates the dynamics response of rail grinding train under the different operation speeds and different wind scales, and calculates the lateral force of wheel axle, wheel/rail vertical force, derailment coefficient, wheel load reduction and overturning coefficient. Analysis of the influence of operation speed, wind scale and line type on operation safety parameters. The results showed that:when there is no wind, the operation safety parameters were within the GB/T17426-1998 range, while under strong side wind, the derailment coefficient, wheel load reduction and overturning coefficient that exceeded the standard limit values, the safety of rail grinding train under strong side wind operational is worse than no wind; under the aerodynamic loads, the leeward side of the wheels ware extruded by the rail, the leeward side of the wheel/rail vertical force and derailment coefficient greater than the windward side. The operation safety parameters with the running speed increase is significantly less than the increase in wind scale increased growth, the impact of wind scale on the safety parameters was larger than that effect by running speed. Comparison of two calculated type of curve, under the conditions of rail irregularity, aerodynamic loads, centripetal and centrifugal forces, the parameters increase with the increase of running speed for the left curve, while to the right curve, derailment coefficient and wheel load reduction rate positive correlation with speed, the lateral force of wheel axle, wheel/rail vertical force and overturning coefficient negative correlation with speed.Through analyzing the wheel/rail dynamics parameters indicators of various line types by different running speeds and wind scales, limit speed value of the rail grinding train under the strong side wind in this line condition has been obtained. The results of this paper can provide some references for the safe operation of rail grinding train under strong side wind. |
