Method for simulating heavy gas to diffuse in city streets with wind

Abstract

The invention discloses a method for determining subway station structure stressed situation in fire. The method is characterized in that diffusion of a cellular automata (AC)-air mass model is simulated, gas macroscopic diffusion is taken as multiple air masses in an equivalent manner, the cellular automata is allowed to generate a moving model of the air masses, the air mass characteristics are expressed as Qi (Vi0, xi, yi), the Gaussian model is referred to determine an influence radius D to distinguish concentration gradient diffusion Sd and free diffusion Sf, the strength distribution of the wind in the streets is determined, a boundary contacting condition is constructed, a simulated city environment is assumed, the model is used to simulate ammonia diffusion when the wind speed is equal to 0.75 m / s, and influences on diffusion can be studied when the wind enters the streets in different moments. The method includes determining the influence radius D, determining an air mass automata model, determining change amount of air mass moving speed changes, determining wind field distribution, determining the boundary contacting condition, and setting model establishing parameters to simulate. The method can be applied in gas diffusion distribution simulation with the wind in conditions of complex arrangement of the city streets.

Description

technical field [0001] The present invention relates to heavy gas diffusion simulation, especially involving Study on the diffusion of heavy air in windy conditions in complex urban blocks. Background technique [0002] The air quality of cities is closely related to people's lives, and the pollutants emitted by people's production and living processes are the main factors causing urban air pollution. Especially in the streets of the city, the leakage caused by transportation or transportation cannot be effectively controlled in a short period of time. In addition, the urban pad surface is dry, hot, rough, etc., and its complexity leads to the urban wind environment and the diffusion of pollutants. become very complicated. It is of great significance to improve people's living environment to explore the mechanism and law of pollutant diffusion in complex block layout under the action of wind. [0003] There have been many studies on gas diffusion in China, but th...

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Problems solved by technology

[0003] There have been many studies on gas diffusion in China, but these studies are mainly carried out by applying the regular and continuous model of the diffusion range, which cannot be applied to the diffusion of heavy gas in the irregular and discontinuous topological structure of the near-surface urban blocks. simulation, and rarely consider the influence of wind flow in the block on the diffusion of heavy gas

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