CN-121997835-A - High and cold motor train unit roadbed foreign matter adsorption critical condition prediction method and system based on aerodynamics

CN121997835ACN 121997835 ACN121997835 ACN 121997835ACN-121997835-A

Abstract

The application relates to the field of rail traffic safety technology and aerodynamics, and provides a method and a system for predicting a roadbed foreign matter adsorption critical condition of a high and cold motor train unit based on aerodynamics, wherein the method comprises the steps of establishing a three-dimensional geometric model and a vehicle body coordinate system of a corresponding motor train unit; the method comprises the steps of constructing a flow field calculation domain under a vehicle body coordinate system, arranging a plurality of pressure monitoring points, simulating by taking the running speed of a target train as the incoming flow speed to obtain an adsorption negative pressure characteristic value, constructing a physical model of foreign matters, establishing a critical take-off condition for foreign matters adsorption based on the mechanical balance relation between the adsorption negative pressure characteristic value and the gravity of the foreign matters, substituting the critical size and critical mass of the foreign matters into a density parameter of the foreign matters, and solving. According to the method, the critical size and critical mass of the foreign matters can be quantitatively given under the condition of the running speed of a given train, prediction of the critical condition of adsorption of the foreign matters on the roadbed is realized, and basis is provided for running safety assessment and foreign matters risk management and control of the motor train unit under the severe cold working condition.

Inventors

YU YIZHENG
ZHOU WEI
LIU XINZHEN
WANG FENG
LIU KUN
WANG ZHIXIN
WANG YAZHAO
PANG JIAHONG

Assignees

中车长春轨道客车股份有限公司
中南大学

Dates

Publication Date: 20260508
Application Date: 20260130

Claims (8)

1. The method for predicting the critical condition of the adsorption of the foreign matters on the roadbed of the high and cold motor train unit based on aerodynamics is characterized by comprising the following steps: s1, obtaining geometric parameters of a motor train unit to be predicted, establishing a three-dimensional geometric model based on the geometric parameters, and establishing a vehicle body coordinate system corresponding to the three-dimensional geometric model; S2, under a vehicle body coordinate system, constructing an external flow field calculation domain around the motor train unit based on the three-dimensional geometric model, and arranging a plurality of pressure monitoring points at positions corresponding to the roadbed surface in the external flow field calculation domain; s3, constructing a physical model of the foreign matter, and setting density parameters and geometric shapes of the foreign matter; S4, establishing a critical take-off condition for foreign matter adsorption based on the mechanical balance relation between the adsorption negative pressure characteristic value and the gravity of the foreign matter, and solving based on the density parameter and the geometric shape of the foreign matter; s5, outputting a predicted result of the critical condition of foreign matter adsorption corresponding to the target train running speed and the roadbed surface, wherein the predicted result at least comprises the critical size of the foreign matter and the critical mass of the foreign matter.
2. The method for predicting the critical conditions for the adsorption of foreign matters on the roadbed of an alpine motor train unit based on aerodynamics according to claim 1, wherein the foreign matters include at least spherical foreign matters and cubic foreign matters, and the spherical foreign matters are formed in a radius Characterization, cubic foreign body with side length Characterization.
3. The method for predicting the adsorption critical condition of the roadbed and the foreign matter of the alpine motor train unit based on the aerodynamics according to claim 2, wherein the adsorption critical take-off condition of S4 is as follows: The critical equilibrium equation established by the spherical foreign matter is: the critical equilibrium equation established by the cubic foreign matter is: in the formula, In order to adsorb the characteristic value of the negative pressure, Gravitational acceleration; Is the density of the corresponding foreign matter; The critical size and critical mass of the foreign matter are obtained by solving a critical balance equation based on the geometric shape, the density parameter and the corresponding geometric shape of the foreign matter.
4. The method for predicting the critical condition of roadbed foreign matter adsorption of an alpine motor train unit based on aerodynamics according to claim 1, wherein the foreign matter comprises at least railway ballast, ice and ice-covered railway ballast mixture, and the density of the ice-covered railway ballast mixture is determined by the density of railway ballast, the density of ice and the volume ratio of railway ballast to ice And (5) weighting and confirming, wherein the calculation formula is satisfied: in the formula, Is the density of the railway ballast; In order to achieve a density of ice, Is the density of the ice-covered road ballast mixture, and the volume ratio of the ballast ice The range of the values is as follows 。
5. The method for predicting the critical conditions for roadbed foreign matter adsorption of an alpine motor train unit based on aerodynamics according to claim 1, wherein the geometric parameters of the motor train unit at least comprise a vehicle body geometric parameter, a head geometric parameter, a simplified bogie geometric parameter, and a full length, a total width and a total height, wherein the train feature scale is selected as the total height, and the flow field calculation domain size is determined based on the train feature scale.
6. The method for predicting the critical conditions for roadbed foreign matter adsorption of the alpine motor train unit based on aerodynamics according to claim 1 is characterized in that the boundary conditions comprise that the roadbed surface at the bottom of a flow field calculation domain is a sliding wall surface, the sliding speed is consistent with the incoming flow speed, the surfaces of a vehicle body and a bogie are non-sliding wall surfaces, and the rest boundaries are symmetrical planes.
7. The method for predicting the critical condition for adsorption of the roadbed and the foreign matters of the high and cold motor train unit based on the aerodynamics according to claim 1, wherein in the step S2, the simulation adopts a time step to perform time propulsion, and the pressure monitoring points are subjected to pressure sampling within a preset calculation duration to form the pressure fluctuation curve.
8. A critical condition prediction system for adsorption of foreign bodies on a road bed of a high and cold motor train unit, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any one of claims 1 to 7 when executing the computer program.

Description

High and cold motor train unit roadbed foreign matter adsorption critical condition prediction method and system based on aerodynamics Technical Field The application relates to the fields of rail traffic safety technology and aerodynamics, in particular to a method and a system for predicting a critical condition of adsorption of foreign matters on a roadbed of a high and cold motor train unit based on aerodynamics. Background The running environment of the motor train unit in the alpine region is bad, and snow, ice slag and ice layers often cover railway ballasts on the track in winter. When the train passes at high speed, complex flow field changes can be generated between the bottom of the train and the ground, and particularly, strong pneumatic negative pressure can be formed at the bottom of the train body, so that pneumatic adsorption force is generated. The pneumatic adsorption force is sufficient to overcome the gravity of the foreign matters on the roadbed, and the foreign matters are sucked up and hit the bogie and the bottom equipment of the train, so that the equipment is damaged, and the driving safety is seriously threatened. The existing countermeasure is dependent on empirical speed limit or post-overhauling, and lacks a prediction method capable of quantitatively calculating and predicting how large and large the foreign matters with different sizes and mass are sucked up under different speeds, so that accurate data support cannot be provided for winter driving speed limit and line snow cleaning standards. Disclosure of Invention The application aims to solve the technical problem of lack of adsorption conditions of foreign matters on the bottoms of motor train units in severe cold regions and provides a prediction method and a prediction system of adsorption critical conditions of roadbed foreign matters of the motor train units based on aerodynamics. In order to achieve the above object, a first aspect of the present application provides an aerodynamic-based method for predicting a critical condition for adsorption of foreign matters on a roadbed of an alpine motor train unit, comprising: s1, obtaining geometric parameters of a motor train unit to be predicted, establishing a three-dimensional geometric model based on the geometric parameters, and establishing a vehicle body coordinate system corresponding to the three-dimensional geometric model; S2, under a vehicle body coordinate system, constructing an external flow field calculation domain around the motor train unit based on the three-dimensional geometric model, and arranging a plurality of pressure monitoring points at positions corresponding to the roadbed surface in the external flow field calculation domain; s3, constructing a physical model of the foreign matter, and setting density parameters and geometric shapes of the foreign matter; S4, establishing a critical take-off condition for foreign matter adsorption based on the mechanical balance relation between the adsorption negative pressure characteristic value and the gravity of the foreign matter, and solving based on the density parameter and the geometric shape of the foreign matter; s5, outputting a predicted result of the critical condition of foreign matter adsorption corresponding to the target train running speed and the roadbed surface, wherein the predicted result at least comprises the critical size of the foreign matter and the critical mass of the foreign matter. In an embodiment of the application, the foreign body geometry comprises at least a sphere and a cube, the sphere foreign body having a radiusCharacterization, cubic foreign body with side lengthCharacterization. In the embodiment of the present application, in the adsorption critical takeoff condition of S4: The critical equilibrium equation established by the spherical foreign matter is: the critical equilibrium equation established by the cubic foreign matter is: in the formula, In order to adsorb the characteristic value of the negative pressure,Gravitational acceleration; Is the density of the corresponding foreign matter; The critical size and critical mass of the foreign matter are obtained by solving a critical balance equation based on the geometric shape, the density parameter and the corresponding geometric shape of the foreign matter. In the embodiment of the application, the types of the foreign matters at least comprise railway ballasts, ice and an ice-covered railway ballast mixture, wherein the density of the ice-covered railway ballast mixture is determined by the density of railway ballasts, the density of ice and the volume ratio of railway ballasts to iceAnd (5) weighting and confirming, wherein the calculation formula is satisfied: in the formula, Is the density of the railway ballast; In order to achieve a density of ice, Is the density of the ice-covered road ballast mixture, and the volume ratio of the ballast iceThe range of the values is as follows。 In the embodiment of the