Longitudinal Dynamics Test And Simulation Study On Shen-hua 10000t Heavy Haul Train

Heavy-haul railway transport as the main development of railway freight transportation,by many countries got importance.According to domestic and abroad practical operations,test and theoretical studies on heavy-haul train,with the increase of traction weight and vehicle axle weight,the longitudinal impulse of the train becomes complex and intense,which brings a series of issues that had affected the safety of railway operation.As the second channel for transporting coal from westen to easten China,Shenhua railway have an increasing number of freight volume year by year.However,there were very limited studies on the longitudinal dynamics of Shenhua railway heavy-haul train.Therefore,it is great significance to conduct test and simulation to study the longitudinal impulse generation mechanism,train braking system characteristic,vehicle dynamic model for Shenhua railway's heavy-haul train,especially for the safe operation of these heavy-haul trains.In view of it,this paper takes heavy-haul train on Shenwan railway as the object of the study,and use both test and simulation to study its longitudinal dynamics.The test items for ten-thousand-ton heavy-haul train on Shenhua railway are the longitudinal coupler force,buffer compression and brake system pressure.Multi-sectional unattended synchronous acquisition method is used in the test to measure the longitudinal impulse and braking system during the whole running of the train.Through the reasonable processing of the collected data,this paper obtains accurate and effective test data,and then come to the following conclusions by the synchronization analysis with locomotive manipulation data and line parameters: Both maximum coupler pulling force and coupler compressing force are occurred on Shenshuo railway section,which are-1221 kN and 1301 kN respectively.The overall level of coupler force on Shuohuang railway is lower than Shenshuo railway.For the five sections that have more than 800 kN coupler force.The average braking time is 58 times for full-train and 8 times for empty-train.The brake pipe reducing is mainly between 40-60 kPa and 100-130 kPa.Additionally,the characteristics of brake wave are obtained under different marshalling way and decompression quantities.Furthermore,by analyzing the data of station start,stop,dumping and cycle braking,the longitudinal dynamic response and braking system characteristics of the train under typical working conditions are obtained.The propulsion resistance model of RRTTC and the actual difference were discussed by analysing the test results of idle running on straight lines.A new propulsion resistance model was established by using the ant colony algorithm,and was validated by using the test results of idle running on both straight lines and gradient lines.The result shows: The new model can accurately calculate the change of the idling speed and displacement of the train under different conditions.By selecting two most representative lines on Shenhua Railway as the optimization subject,this paper's objective is to reduce the maximum longitudinal force of the train.By changing the marshalling ways and locomotive control mode as method,this paper conduct optimization to the actual operation of the train process while ensuring the running efficiency of the train.Two sets of optimization schemes are proposed in this paper.The result shows that the two optimization methods can both reduce the maximum coupler force by 50%.The optimal grouping scheme are chosen according to the complexity of the workflow process in the locomotive grouping process.Based on the new propulsion resistance model,the overall traction current-slope-velocity model was established.According to this model,the maximum traction current of the locomotive can be selected according to the different slope and speed,therefore,optimization method are obtained.By comparing the test data,it can be seen that the maximum coupler force can be reduced by 10% when the optimized operation scheme is adopted while ensuring the running efficiency of the train.Based on the analysis of the test results of the air-recharging time test for the single locomotive marshalling and multi-locomotive marshalling,the air-recharging gas flow model was used to calculate the air-recharging time of different marshalling train.The air-recharging time expression of six marshalling train was got.This paper analyzes the impact of marshalling way on the air-recharging time.The results show: When the locomotive has centralized on the forepart of the train,the shortening of air-recharging time is non-proportional to the increase number of locomotive.That is,the 2+0 marshalling has a 15% less air-recharging time than the 1+0 train,while the 3+0 marshalling has a 20% less air-recharging time than the 1+0 train.The air-recharging time of distributed power marshalling compared to head-end marshalling is saved 65%.The effect of pipe reduction and marshalling way on the initial speed of cycle brake release was analysed.The results show: With the increase of pipe reduction,the initial speed of release is gradually reduced,and the decrease rate increases with the increase of slope.With the increase of pipe reduction,the distributed power marshalling to ease the initial speed of release to enhance the effect gradually.The distributed power marshalling can significantly increase the initial speed of releasel,and the increase rate increases with the increase slope.The initial speed of release for 1+1+0 is 1.2~1.7 times faster than 2+0,and the 1+1+1 marshalling has a 1.3~2.0 times faster initial speed than 3+0 marshalling.