Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall buil...Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall built in No.1 west airway to separate the two subsystems. A comparison of simulation results and in-site measurements show that the maximum deviation is less than 10%. Further calculations for the case that the ventilation wall in No.1 west airwav is removed to consider the consequences when the two subsystems are merged together. Results of the simulation showthat the total airflow rate increases, and the ventilation resistance of the mine decreases in comparing with that of the foregoing simulation.展开更多
The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can...The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air conditions during the summer of 2020 in Shanghai,China.Self-developed humidity-controlling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and recorded in real-time under three working conditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working conditions,moisture content of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.展开更多
为了保障双燃料船燃料供给系统(Fuel Gas Supply System,FGSS)通风风机安全稳定运行,基于船舶FGSS内通风系统涉及的双璧管风机和燃气准备间风机,对其控制逻辑进行分析,并将控制方式、安全连锁及信号输出输入接口进行标准化配置。结果表...为了保障双燃料船燃料供给系统(Fuel Gas Supply System,FGSS)通风风机安全稳定运行,基于船舶FGSS内通风系统涉及的双璧管风机和燃气准备间风机,对其控制逻辑进行分析,并将控制方式、安全连锁及信号输出输入接口进行标准化配置。结果表明:智能化控制增加了船员操作的便利性,也增加了系统运行的智能化和安全可靠性。研究成果可为FGSS风机控制设计提供一定参考。展开更多
This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positi...This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positioned at distances of 10 cm and 20 cm below the jet inlet. The experiments were realized using 2D Laser Doppler Anemometer (LDA). Different profiles of mean and fluctuating velocities are presented. The presence of a perforated plate strongly modified the airflow pattern compared to an empty enclosure. The velocities above and below the plate depend on several parameters, including the porosity and the plate’s position relative to the inlet slot and the longitudinal position. The difference between the flow velocity above and below the plates could not be related using a universal formula that depends on these parameters. We also investigated the influence of a porous media of a height of 20 cm (a stack of spheres having a diameter of 3.75 cm) located below the perforated plate. The results highlight that the porous medium strengthens the effects of the perforated plate on the flow.展开更多
When performing numerical modeling of fluid flows where a clear medium is adjacent to a porous medium, a degree of difficulty related to the condition at the interface between the two media, where slip velocity exists...When performing numerical modeling of fluid flows where a clear medium is adjacent to a porous medium, a degree of difficulty related to the condition at the interface between the two media, where slip velocity exists, is encountered. A similar situation can be found when a jet flow interacts with a perforated plate. The numerical modeling of a perforated plate by meshing in detail each hole is most often impossible in a practical case (many holes with different shapes). Therefore, perforated plates are often modeled as porous zones with a simplified hypothesis based on pressure losses related to the normal flow through the plate. Nevertheless, previous investigations of flow over permeable walls highlight the impossibility of deducing a universal analytical law governing the slip velocity coefficient since the latter depends on many parameters such as the Reynolds number, porosity, interface structure, design of perforations, and flow direction. This makes the modeling of such a configuration difficult. The present study proposes an original numerical interface law for a perforated plate. It is used to model the turbulent jet flow interacting with a perforated plate considered as a fictitious porous medium without a detailed description of the perforations. It considers the normal and tangential effects of the flow over the plate. Validation of the model is realized through comparison with experimental data.展开更多
文摘Through the usage of simulation software based on the network layout, airway resistances and parameters of main fans, ventilation calculations were performed to analyse the current situation as a ventilation wall built in No.1 west airway to separate the two subsystems. A comparison of simulation results and in-site measurements show that the maximum deviation is less than 10%. Further calculations for the case that the ventilation wall in No.1 west airwav is removed to consider the consequences when the two subsystems are merged together. Results of the simulation showthat the total airflow rate increases, and the ventilation resistance of the mine decreases in comparing with that of the foregoing simulation.
基金financially supported by the National Natural Science Foundation of China(No.51778358)the Shanghai Municipality Natural Science Foundation(No.21ZR1434400)Sponsored by Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China(LNTCCMA-20210103).
文摘The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air conditions during the summer of 2020 in Shanghai,China.Self-developed humidity-controlling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and recorded in real-time under three working conditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working conditions,moisture content of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.
文摘为了保障双燃料船燃料供给系统(Fuel Gas Supply System,FGSS)通风风机安全稳定运行,基于船舶FGSS内通风系统涉及的双璧管风机和燃气准备间风机,对其控制逻辑进行分析,并将控制方式、安全连锁及信号输出输入接口进行标准化配置。结果表明:智能化控制增加了船员操作的便利性,也增加了系统运行的智能化和安全可靠性。研究成果可为FGSS风机控制设计提供一定参考。
文摘This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positioned at distances of 10 cm and 20 cm below the jet inlet. The experiments were realized using 2D Laser Doppler Anemometer (LDA). Different profiles of mean and fluctuating velocities are presented. The presence of a perforated plate strongly modified the airflow pattern compared to an empty enclosure. The velocities above and below the plate depend on several parameters, including the porosity and the plate’s position relative to the inlet slot and the longitudinal position. The difference between the flow velocity above and below the plates could not be related using a universal formula that depends on these parameters. We also investigated the influence of a porous media of a height of 20 cm (a stack of spheres having a diameter of 3.75 cm) located below the perforated plate. The results highlight that the porous medium strengthens the effects of the perforated plate on the flow.
文摘When performing numerical modeling of fluid flows where a clear medium is adjacent to a porous medium, a degree of difficulty related to the condition at the interface between the two media, where slip velocity exists, is encountered. A similar situation can be found when a jet flow interacts with a perforated plate. The numerical modeling of a perforated plate by meshing in detail each hole is most often impossible in a practical case (many holes with different shapes). Therefore, perforated plates are often modeled as porous zones with a simplified hypothesis based on pressure losses related to the normal flow through the plate. Nevertheless, previous investigations of flow over permeable walls highlight the impossibility of deducing a universal analytical law governing the slip velocity coefficient since the latter depends on many parameters such as the Reynolds number, porosity, interface structure, design of perforations, and flow direction. This makes the modeling of such a configuration difficult. The present study proposes an original numerical interface law for a perforated plate. It is used to model the turbulent jet flow interacting with a perforated plate considered as a fictitious porous medium without a detailed description of the perforations. It considers the normal and tangential effects of the flow over the plate. Validation of the model is realized through comparison with experimental data.
