Method for calculating position of middle air shaft at entrance section of high-speed subway tunnel

Abstract

The invention discloses a calculation method for reasonably arranging the position of a middle air shaft at an entrance section of a high-speed subway tunnel, which comprises the following steps of: simultaneously acting an expansion wave reflected by the middle air shaft at the entrance section and an expansion wave generated when the tail of a subway train drives into a tunnel portal on the train, and spreading a compression wave and the expansion wave in the subway tunnel at sound velocity; in order to avoid the situation that expansion waves generated when the tail of a subway train drives into a tunnel portal and expansion waves reflected by a middle air shaft at the tunnel entrance section are overlapped and act on the surface of the train at the same time, conditions met by the position of the middle air shaft at the tunnel entrance section are established based on aerodynamics; the change relation of the expansion waves, the compression waves and the train head and train tail positions of the subway train along with time is obtained, and expressions of the time when the expansion waves reflected by the middle air shaft and the expansion waves generated when the train tail of the subway train enters the tunnel act on the train carriage start and end are further deduced. Finally, the distance between the middle air shaft and the tunnel entrance is determined, so that the comfort problems of ear discomfort, eardrum pain and the like of passengers, drivers and conductors are solved.

Description

technical field [0001] The invention relates to the technical field of aerodynamics of high-speed subway tunnels, in particular to a calculation method for reasonably setting the position of an intermediate air shaft at an entrance section of a high-speed subway tunnel. Background technique [0002] Urban rail transit is the development direction of modern metropolitan transportation. The development of rail transit is an effective way to solve the problems of big cities, and it is also an effective way to build green cities and smart cities. The motion of a high-speed train causes significant changes in the airflow around the train, and also changes the airflow around the train over a certain distance. Different from running on the open line, when the train passes through the tunnel opening at high speed, due to the constraints and blocking effects of the tunnel wall, the gas in front of the front of the train cannot diffuse to the surroundings in time, and undergoes sever...

AI Technical Summary

Problems solved by technology

Compression waves and expansion waves propagate at the speed of sound in the tunnel and are repeatedly reflected in the tunnel, causing drastic pressure changes in the tunnel, on the surface of the tunnel, on the outer surface of the train, and inside the car. The interior deteriorates the riding environment. When the pressure fluctuation and pressure gradient in the car exceed a certain value, it will cause comfort problems such as ear discomfort and eardrum pain for passengers, drivers and passengers.

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