土木工程畢業(yè)設(shè)計(jì)外文翻譯---cfd模擬和地鐵站臺的優(yōu)化通風(fēng)（節(jié)選）-建筑結(jié)構(gòu)(文件)
【正文】 esis makes putational fluid dynamics (CFD) simulation to subway sideplatform station with the boundary conditions collected for simulation putation through field measurement. It is found that the twoequation turbulence model can be used to predict velocity field and temperature field at the station under some reasonable presumptions in the investigation and study. At last, an optimization ventilation mode of subway sideplatform station was put forward. 1. Introduction Computational fluid dynamics (CFD) software is monly used to simulate fluid flows, particularly in plex environments (Chow and Li, 1999。 Papakonstantinou et al., 2020。 Vardy et al., 2020。 Carvel et al., 2020。 Tajadura et al., 2020) have done much work on this. This paper studied the performance of CFD simulation on subway environment control system which has not been studied by other paper or research report. It is essential to calculate and simulate the different designs before the construction begins, since the investment in subway’s construction is huge and the subway should run up for a few decade years. The ventilation of subway is crucial that the passengers should have fresh and high quality air (Lowndes et al., 2020。 Gehrke et al., 2020), so the period the simulation concerns about the best period of time for simulation is from the point when at the section of ‘x = m’ (Fig. 1) and the air velocity begin to change under pistoneffect to the point when train totally stops at the station (defined as a ‘pullingin cycle’). (2) Though the pullingin cycle is a transient process, it is simplified to a steady process. (3) Because the process is presumed to a steady process, the transient velocity of test sections, which was tested in Southwest Station in pullingin cycle, is presumed to the timeaveraged velocity of test sections. 外文資料翻譯 第 5 頁 (4) The volume flow driven into the station by pullingin train is determined by such factors as BR (blocking ratio, the ratio of train crosssection area to tunnel crosssection area), the length of the train and the resistance of station etc. For existent and new stations, BRs are almost the same. Although the length of the latter train doubles that of the former which may increase the piston flow volume, the resistance of latter is greater than that of the former which may counteract this increase. So it is presumed that the piston flow volume is same for both existent and new station and that the volume flow through the passenger exits is also same. Based on this presumption, the results of the field measurements at the existent station can be used as velocity boundary conditions to predict velocity filed of new station. . Original conditions To obtain the boundary conditions for putation and simulation, such as the air velocity and temperature of enclosure, measures were done by times at Southwest Station. All data are recorded during a plete pullingin cycle. The air velocities were measured by the multichannel anemonemaster hotwire anemoscope and infrared thermometer is used to measure the temperature of the walls of the station which are ta
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