The study of aerodynamic processes in railway tunnels on highspeed railways in the absence of practical experience in operation should be carried out with a sufficient degree of accuracy only by mathematical modeling. A multi-factor experiment was performed, which resulted in solving the optimization task of determining the tunnel cross-sectional area, taking into account aerodynamic processes. Based on the analysis of the results, the conclusion is made about the applicability of the method to the prognosis of aerodynamic effects on prospective tunnel structures of high-speed railways and optimization of geometric parameters of the tunnels.
BACKGROUND: During the operation of crane beams of lifting equipment of subway tunnel escalators machine halls, the information about the technical condition of certain structural elements of supporting metal framework is always relevant, which determines the possibility of their further safe use and the need for repair and restoration work. The value of the remained service life is estimated by comparing the actual load-carrying ability with the criteria corresponding to the limiting conditions according to the project documentation. The actual state of the supporting framework elements can change with time significantly, therefore, the assessment of the remained service life is carried out with an experiment-and-simulation method based on the determination of stresses and their maximum deviations in weakest sections of framework elements with the determination of the degree of their impact on durability in the long term. AIMS: Analysis of the combined application of methods for modeling the stress-strain state with subsequent wavelet analysis of wave processes in the interlocked stud-bolts of the suspension unit of riding beams of lifting and transport equipment of subway tunnel escalators machine halls. METHODS: With regard to the specific features of the design, numerical simulation of the technical state of the interlocked sections of the stud-bolted suspension of crane beams of lifting equipment of subway tunnel escalators machine halls is considered in this work. The capabilities of the Simulation (static analysis using the finite element method) and Motion (kinematic and dynamic research with formation of systems of differential equations of motion and subsequent solving) modules of the SolidWorks software platform were used in the development of the model. RESULTS: As a result of the carried out research, with regard to the specific features of various methods of the stress-strain state simulation, a spatial linear dynamic model has been developed that reflects the processes occurring during the deformation of the stud-bolt suspension of the supporting I-beam, which is helpful for an objective assessment of its technical state, as well as the possibility and conditions of further operation. CONCLUSIONS: To simulate the stress-strain state, the combined application of methods is necessary, followed by a wavelet analysis of wave processes, which increases the reliability of diagnostic procedures and, consequently, makes it possible to make reasonable decisions about the further operation of the facility.
Purpose: Numerical simulation of aerodynamic interaction of a moving high-speed train with a wind load applied to the side surface of the train body elements during its exit from the tunnel to the open space is considered. The stability of the rolling stock was assessed according to the criterion of the minimum pressure of the weight load on the wheel. Methods: CFD modeling allows you to significantly expand the amount of information about the interaction of rolling stock with incoming air flow in various environmental conditions. Results: During numerical modeling, the pressure values on the surface of the housing elements of the composition in the overpressure zones and the underpressure zones were obtained. Besides, areas of application of these loads on car surface are defined. Practical significance: It was established that in case of exceeding the speed of air masses by 20% higher than the maximum recorded on the terrain of the northeastern plateau of the right bank of Angren in the prevailing wind direction, an unacceptable decrease in the weight load on the front trolley on the left wheel is possible.
Purpose: Development of mathematical models allowing to investigate the processes of aeroelastic interaction of a rolling stock with portal buildings of passover tunnels in dynamic and quasi-stationary setting with the use of deformable mobile nets and FrozenRotor methods. Methods: we present mathematical models and ways of their realization in two- and three-dimensional setting in program complexes Comsol Multiphysics and Solid Works Flow Simulation on the basis of numerical solution of Reynolds averaged NavierStoks Method (RANS) method equations. Results: The results of numerical research of velocity and pressure fields nearby tunnel portal zone, obtained with the help of developed mathematical models for the case of rolling stock entrance into a tunnel, ‘re given. Practical importance: It’s revealed that at train entrance into a tunnel, air mass runaway by a rolling stock is made with significant delay owing to effect of viscous friction force between an air and tunnel walls as well as inside air volume which fills a tunnel.
Purpose: The development of recommendations on the improvement of energy efficiency and safety of freight and passenger transportation process on the basis of the analysis of aerodynamic interaction processes between moving rolling stock and tunnel-type artificial structures. To study the effect of air flow on electric rolling stock (ERS) and locomotive crew using SolidWorks program, Flow Simulation module. Methods: Investigation of the principle of formation of air environment structure in the portal part area of standard type tunnel structure that’s equipped with means for leveling air pressure fluctuations by air mass movement modeling by “braked rotor” method. Results: The design of tunnel portal part was developed and numerical study in the SolidWorks Flow Simulation environment was carried out. At tunnel entrance and exit, it is possible to reduce several times air flow velocity, affecting ERS and tunnel structures, as well as to stabilize air mass pressure and to bring atmospheric pressure closer to normal one. Practical significance: The proposed design allows to improve cargo and passenger transportation quality and namely to reduce negative pressure and velocity of air flow, affecting locomotive crews, passengers and tunnel structures as well as to lower electric rolling stock power consumption.
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