Numerical simulation of flow field characteristics and pollutant transport under different ventilation modes

Abstract

Toxic and harmful gases generated during tunnel construction endanger the life and health of construction personnel. Reasonable design and solution of ventilation problems become the key to ensure the safety of engineering construction. By repeatedly selecting model parameters and calculation methods, this paper establishes a reasonable model to simulate tunnel ventilation engineering. By simulating the distribution of the flow field in the tunnel under various ventilation modes, the mechanism of the turbulent air flow generated by the restriction of jet and wall is proved. The retarding effect of vortex region on pollutant transport is analyzed. The results showed that the retarding effect of vortex and pollutant transport diffusion mechanism resulted in two peak distributions of pollutants. The mechanism of fan accelerating pollutant transport in stagnation zone was also revealed. The time cost law of ventilation saving under different modes is found through comparison. According to the distribution characteristics of flow field and the migration rules of pollutants under various ventilation modes, a new annular ventilation mode is proposed, which provides a reference for the optimization of engineering ventilation time. By comparing different ventilation modes, optimization measures are proposed for specific projects.

Microclimate Regulation in Glass Greenhouses

“…The position of the fan should take into account the hot spot and dead Angle position in the greenhouse, and the installation of the fan in these places to achieve effective ventilation and circulation of air can effectively improve the uniformity of the wind. [6] 3. Excessive wind speed will cause a slight increase in temperature near the fan and in some areas inside the greenhouse.…”

“…The setting of initial conditions has an important influence on the accuracy and stability of simulation results. (6) In this case, we're going to set the initial condition to be a uniform initial temperature.…”