Pub Date : 2021-11-23DOI: 10.1080/14733315.2021.2004662
Yuanlong Zhou, Honglin Wang, Haiquan Bi
Abstract Rescue station is an important part of the extra-long railway tunnel, which can provide smoke-free refuge for evacuated passengers. For the fire research of the rescue station, the influence of the burning train running on the smoke spread characteristics has not been considered in the previous studies. In this work, the influence of the train running on the fire smoke spread characteristics in the rescue station was investigated using the numerical method, and the accuracy of the numerical methodology was confirmed by the 1:20 scale model experiment. Then, the influence of the burning train running on the temperature and visibility distribution in the rescue station was analysed by dynamic and static simulation. The results demonstrate that the temperature and soot density of the smoke are low when the burning train was running in the tunnel, which makes fire detection very difficult. For the smoke spread characteristics of the rescue station, the main impact of the burning train running is visibility, and the influence time is 30 s when the heat release rate of the fire source was 15 MW. For dynamic simulation, when the burning train stops at the rescue station, the maximum heat transfer power between the smoke at the top of the tunnel and the concrete lining is 1.51 MW, accounting for 10.1% of the heat release rate of the fire source.
{"title":"Influence of the train running on the fire smoke spread characteristics in the rescue station","authors":"Yuanlong Zhou, Honglin Wang, Haiquan Bi","doi":"10.1080/14733315.2021.2004662","DOIUrl":"https://doi.org/10.1080/14733315.2021.2004662","url":null,"abstract":"Abstract Rescue station is an important part of the extra-long railway tunnel, which can provide smoke-free refuge for evacuated passengers. For the fire research of the rescue station, the influence of the burning train running on the smoke spread characteristics has not been considered in the previous studies. In this work, the influence of the train running on the fire smoke spread characteristics in the rescue station was investigated using the numerical method, and the accuracy of the numerical methodology was confirmed by the 1:20 scale model experiment. Then, the influence of the burning train running on the temperature and visibility distribution in the rescue station was analysed by dynamic and static simulation. The results demonstrate that the temperature and soot density of the smoke are low when the burning train was running in the tunnel, which makes fire detection very difficult. For the smoke spread characteristics of the rescue station, the main impact of the burning train running is visibility, and the influence time is 30 s when the heat release rate of the fire source was 15 MW. For dynamic simulation, when the burning train stops at the rescue station, the maximum heat transfer power between the smoke at the top of the tunnel and the concrete lining is 1.51 MW, accounting for 10.1% of the heat release rate of the fire source.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"36 1","pages":"40 - 55"},"PeriodicalIF":1.5,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87842129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-13DOI: 10.1080/14733315.2021.1975062
M. Georgescu, A. Meslem, I. Năstase, L. Tacutu
Abstract This article presents the study of a ventilation solution using cross-flow fans for the crew quarters (CQ) aboard the International Space Station. Currently the CQ uses two axial fans for ventilation, which occasionally generate insufficient flow rate or acoustic issues. A ventilation circuit using two cross-flow fans was designed, its acoustic performance was measured and the flow was investigated via CFD by using the measured cross-flow fan operating curves as boundary conditions. The acoustic performance of the fans was evaluated in isothermal conditions, under the assumption that the heat generated by the occupants and equipment would produce negligible thermal buoyancy effects in microgravity on the station. Future studies will investigate how the internal heat generated in the enclosure affects the thermal comfort conditions of the occupants. After a comparison between the axial and cross-flow fan systems, results indicate that the latter provides better acoustic parameters for the same flow rate with less energy consumption.
{"title":"An alternative air distribution solution for better environmental quality in the ISS crew quarters","authors":"M. Georgescu, A. Meslem, I. Năstase, L. Tacutu","doi":"10.1080/14733315.2021.1975062","DOIUrl":"https://doi.org/10.1080/14733315.2021.1975062","url":null,"abstract":"Abstract This article presents the study of a ventilation solution using cross-flow fans for the crew quarters (CQ) aboard the International Space Station. Currently the CQ uses two axial fans for ventilation, which occasionally generate insufficient flow rate or acoustic issues. A ventilation circuit using two cross-flow fans was designed, its acoustic performance was measured and the flow was investigated via CFD by using the measured cross-flow fan operating curves as boundary conditions. The acoustic performance of the fans was evaluated in isothermal conditions, under the assumption that the heat generated by the occupants and equipment would produce negligible thermal buoyancy effects in microgravity on the station. Future studies will investigate how the internal heat generated in the enclosure affects the thermal comfort conditions of the occupants. After a comparison between the axial and cross-flow fan systems, results indicate that the latter provides better acoustic parameters for the same flow rate with less energy consumption.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"24 1","pages":"24 - 39"},"PeriodicalIF":1.5,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82803058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-09DOI: 10.1080/14733315.2021.1971872
Zhenhai Wu, Qinwen Xu, Changming Ling
Abstract A three-dimensional model of an enclosed air-conditioned space was established. Numerical simulation was conducted for the temperature distribution in the enclosed space with the air conditioner turned on using computational fluid dynamics, and the movement track of aerosol droplets exhaled by a patient in the enclosed space was traced using the discrete phase model based on the Eulerian–Lagrangian method. The analysis shows that, after the air conditioner is turned on, the velocity and temperature of outflowing air from the air conditioner greatly influence the temperature field and the movement track of aerosol in the enclosed space. With the change of intake air temperature, there is little difference in the absorption of aerosol by air conditioning; When the air velocity of outflowing air from the air conditioner is 0.8 m/s-2m/s, the amount of aerosol absorbed by the air conditioner increases with the increase of air velocity of outflowing air from the air condition. Equipping the air conditioner with an aerosol filter can prevent the aerosol droplets from exiting of the air conditioner again and decrease the quantity of aerosol particles in the enclosed space, thus reducing the risk of airborne viruses infecting susceptible people. In some public places where central air conditioning is used, aerosol filters can also avoid transmitting aerosols to other spaces through the central air conditioning system.
{"title":"Numerical simulation of droplet aerosol transmission in an enclosed space","authors":"Zhenhai Wu, Qinwen Xu, Changming Ling","doi":"10.1080/14733315.2021.1971872","DOIUrl":"https://doi.org/10.1080/14733315.2021.1971872","url":null,"abstract":"Abstract A three-dimensional model of an enclosed air-conditioned space was established. Numerical simulation was conducted for the temperature distribution in the enclosed space with the air conditioner turned on using computational fluid dynamics, and the movement track of aerosol droplets exhaled by a patient in the enclosed space was traced using the discrete phase model based on the Eulerian–Lagrangian method. The analysis shows that, after the air conditioner is turned on, the velocity and temperature of outflowing air from the air conditioner greatly influence the temperature field and the movement track of aerosol in the enclosed space. With the change of intake air temperature, there is little difference in the absorption of aerosol by air conditioning; When the air velocity of outflowing air from the air conditioner is 0.8 m/s-2m/s, the amount of aerosol absorbed by the air conditioner increases with the increase of air velocity of outflowing air from the air condition. Equipping the air conditioner with an aerosol filter can prevent the aerosol droplets from exiting of the air conditioner again and decrease the quantity of aerosol particles in the enclosed space, thus reducing the risk of airborne viruses infecting susceptible people. In some public places where central air conditioning is used, aerosol filters can also avoid transmitting aerosols to other spaces through the central air conditioning system.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"8 1","pages":"225 - 244"},"PeriodicalIF":1.5,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82811802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.1080/14733315.2021.1969743
V. Leprince, Sylvain Berthault, F. Carrié, Nolwenn Hurel
Abstract Ductwork airtightness test protocols implicitly assume that the pressure across the leaks is identical for all leaks. In fact, the pressure difference at the leaks decreases in absolute value as the distance from the moving air increases, due to friction and dynamic losses. This paper aims to quantify the impact of these pressure losses on airtightness test results, and thereby the measurement error generated by the constant pressure assumption. To this end, we developed an analytical model and performed measurements on an experimental set-up that reproduces residential ductwork at 1:1 scale with dynamic losses that can be modified using dampers. We compared the results obtained using the analytical model and the experimental set-up. The analytical model makes it possible to calculate the maximum “test length” for which the error due to pressure drop remains below 5%. According to this model, the impact of pressure losses on the measured flow rate is very small for airtight ductwork (Class C). In this case, the model shows that a length of 260 m between the measuring device and the far end of the ductwork can be tested at one time, even if the ductwork is quite narrow (average diameter of 200 mm) and the test pressure very high (1000 Pa). However, when testing very leaky ductwork (3*Class A) with an average diameter of 400 mm and a test pressure of 200 Pa, the distance between the measuring device and the far end of the ductwork must be no more than 67 m to limit the error to less than 5%. This model can be used to produce charts giving the maximum length to be tested as a function of the pressure drop and the expected ductwork airtightness class.
{"title":"Assessing the impact of pressure drop and leak distribution on ductwork airtightness measurements","authors":"V. Leprince, Sylvain Berthault, F. Carrié, Nolwenn Hurel","doi":"10.1080/14733315.2021.1969743","DOIUrl":"https://doi.org/10.1080/14733315.2021.1969743","url":null,"abstract":"Abstract Ductwork airtightness test protocols implicitly assume that the pressure across the leaks is identical for all leaks. In fact, the pressure difference at the leaks decreases in absolute value as the distance from the moving air increases, due to friction and dynamic losses. This paper aims to quantify the impact of these pressure losses on airtightness test results, and thereby the measurement error generated by the constant pressure assumption. To this end, we developed an analytical model and performed measurements on an experimental set-up that reproduces residential ductwork at 1:1 scale with dynamic losses that can be modified using dampers. We compared the results obtained using the analytical model and the experimental set-up. The analytical model makes it possible to calculate the maximum “test length” for which the error due to pressure drop remains below 5%. According to this model, the impact of pressure losses on the measured flow rate is very small for airtight ductwork (Class C). In this case, the model shows that a length of 260 m between the measuring device and the far end of the ductwork can be tested at one time, even if the ductwork is quite narrow (average diameter of 200 mm) and the test pressure very high (1000 Pa). However, when testing very leaky ductwork (3*Class A) with an average diameter of 400 mm and a test pressure of 200 Pa, the distance between the measuring device and the far end of the ductwork must be no more than 67 m to limit the error to less than 5%. This model can be used to produce charts giving the maximum length to be tested as a function of the pressure drop and the expected ductwork airtightness class.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"20 1","pages":"122 - 137"},"PeriodicalIF":1.5,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76477828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.1080/14733315.2021.1971873
Sajan Preet, M. K. Sharma, Jyotirmay Mathur, A. Chowdhury, S. Mathur
Abstract An analytical model has been developed for simulating the semi-transparent photovoltaic double-skin façade (STPV-DSF) system to assess its overall performance. The STPV-DSF integrated building can generate electricity, provide daylight illuminance in its indoor area and lowers the energy demand of a building. During the building design phase, complex simulations are required to estimate the overall performance of the STPV-DSF system. The present study's objective is to provide a reliable and straightforward calculation method for estimating the overall performance of the STPV-DSF system. This paper evaluates the overall performance of STPV-DSF system operating under natural ventilation and forced ventilation for summer and winter seasons of Indian’s composite climate. An experimental investigation has also been carried out on STPV-DSF system to validate the model. A good agreement was observed between measured and calculated temperatures of the STPV-DSF system and solar heat gain to indoor area. For given weather conditions, CO2 emissions and environmental cost (carbon price and emitted carbon quantity) have also been calculated for STPV-DSF systems by solving energy formulations. The results depicted that STPV-DSF system under forced ventilation exhibited 4.08%, 9.86% and 14.05% higher energy performance than natural ventilation in summer and winter with less CO2 emissions.
{"title":"Analytical model of semi-transparent photovoltaic double-skin façade system (STPV-DSF) for natural and forced ventilation modes","authors":"Sajan Preet, M. K. Sharma, Jyotirmay Mathur, A. Chowdhury, S. Mathur","doi":"10.1080/14733315.2021.1971873","DOIUrl":"https://doi.org/10.1080/14733315.2021.1971873","url":null,"abstract":"Abstract An analytical model has been developed for simulating the semi-transparent photovoltaic double-skin façade (STPV-DSF) system to assess its overall performance. The STPV-DSF integrated building can generate electricity, provide daylight illuminance in its indoor area and lowers the energy demand of a building. During the building design phase, complex simulations are required to estimate the overall performance of the STPV-DSF system. The present study's objective is to provide a reliable and straightforward calculation method for estimating the overall performance of the STPV-DSF system. This paper evaluates the overall performance of STPV-DSF system operating under natural ventilation and forced ventilation for summer and winter seasons of Indian’s composite climate. An experimental investigation has also been carried out on STPV-DSF system to validate the model. A good agreement was observed between measured and calculated temperatures of the STPV-DSF system and solar heat gain to indoor area. For given weather conditions, CO2 emissions and environmental cost (carbon price and emitted carbon quantity) have also been calculated for STPV-DSF systems by solving energy formulations. The results depicted that STPV-DSF system under forced ventilation exhibited 4.08%, 9.86% and 14.05% higher energy performance than natural ventilation in summer and winter with less CO2 emissions.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"30 1","pages":"138 - 167"},"PeriodicalIF":1.5,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73559628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-31DOI: 10.1080/14733315.2021.1966576
Benedikt Kölsch, I. Walker, Björn Schiricke, W. Delp, B. Hoffschmidt
Abstract Today, the fan pressurization method is the most frequently used method to evaluate a building's airtightness. However, the localization and quantification of leaks remain difficult. In this paper, an acoustic method is introduced to estimate the leakage size of single leaks. Acoustic and airflow measurements were conducted and compared in laboratory tests within the same boundary conditions. This work aims to investigate if various leak sizes can be predicted using acoustic measurement methods. The test apparatus consists of two chambers, separated by a test wall. This wall represents a single characteristic air leakage path. Various types of wall structures with different slit geometries, wall thicknesses, and insulation materials were investigated. The acoustic measurements were performed with a sound source placed in one chamber and ultrasonic microphones located in both chambers. These results were compared to measured airflows through the test wall to provide estimates of uncertainty in the acoustic approach, which indicate a linear trend. Finally, these laboratory measurements were compared to the same measurements at a real office building. Although the acoustic measurement uncertainty is still significant (greater than +/- 50%), the acoustic method has the potential to give an order of magnitude of single leak sizes.
{"title":"Quantification of air leakage paths: a comparison of airflow and acoustic measurements","authors":"Benedikt Kölsch, I. Walker, Björn Schiricke, W. Delp, B. Hoffschmidt","doi":"10.1080/14733315.2021.1966576","DOIUrl":"https://doi.org/10.1080/14733315.2021.1966576","url":null,"abstract":"Abstract Today, the fan pressurization method is the most frequently used method to evaluate a building's airtightness. However, the localization and quantification of leaks remain difficult. In this paper, an acoustic method is introduced to estimate the leakage size of single leaks. Acoustic and airflow measurements were conducted and compared in laboratory tests within the same boundary conditions. This work aims to investigate if various leak sizes can be predicted using acoustic measurement methods. The test apparatus consists of two chambers, separated by a test wall. This wall represents a single characteristic air leakage path. Various types of wall structures with different slit geometries, wall thicknesses, and insulation materials were investigated. The acoustic measurements were performed with a sound source placed in one chamber and ultrasonic microphones located in both chambers. These results were compared to measured airflows through the test wall to provide estimates of uncertainty in the acoustic approach, which indicate a linear trend. Finally, these laboratory measurements were compared to the same measurements at a real office building. Although the acoustic measurement uncertainty is still significant (greater than +/- 50%), the acoustic method has the potential to give an order of magnitude of single leak sizes.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"30 1","pages":"101 - 121"},"PeriodicalIF":1.5,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73464208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-14DOI: 10.1080/14733315.2021.1948720
P. Jia, J. Jia, Lei Song, Zhuang Li, Bin Li
Abstract The intelligentization of mine ventilation is the inevitable development trend of ventilation system. Rapid, precise, and on-demand (RPOD) adjustment of air volume is one of the main problems that need to be solved in mine intelligent ventilation. In order to realize RPOD adjustment of air volume, the concepts of target branch, active branch and passive branch were elaborated and an algorithm was proposed. Then active branches were sorted based on the sensitivity theory, and the adjustment range of the active branches were calculated using the sensitivity attenuation rate theory and the minimum air volume principle. Finally, the specific active branch and adjustment range were determined according to the total air volume that the passive branch. The theory was verified based on the actual ventilation situation of Wuyang Coal Mine in Shanxi Province. The research results will provide theoretical guidance for the RPOD adjustment for mine intelligent ventilation.
{"title":"Theory of RPOD adjustment of air volume for mine intelligent ventilation","authors":"P. Jia, J. Jia, Lei Song, Zhuang Li, Bin Li","doi":"10.1080/14733315.2021.1948720","DOIUrl":"https://doi.org/10.1080/14733315.2021.1948720","url":null,"abstract":"Abstract The intelligentization of mine ventilation is the inevitable development trend of ventilation system. Rapid, precise, and on-demand (RPOD) adjustment of air volume is one of the main problems that need to be solved in mine intelligent ventilation. In order to realize RPOD adjustment of air volume, the concepts of target branch, active branch and passive branch were elaborated and an algorithm was proposed. Then active branches were sorted based on the sensitivity theory, and the adjustment range of the active branches were calculated using the sensitivity attenuation rate theory and the minimum air volume principle. Finally, the specific active branch and adjustment range were determined according to the total air volume that the passive branch. The theory was verified based on the actual ventilation situation of Wuyang Coal Mine in Shanxi Province. The research results will provide theoretical guidance for the RPOD adjustment for mine intelligent ventilation.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"5 1","pages":"316 - 329"},"PeriodicalIF":1.5,"publicationDate":"2021-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75590001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-09DOI: 10.1080/14733315.2021.1943923
Lei Chen, Chunhua Huang, Cheng Xu
Abstract Green buildings and sustainable designs require architectural designers to go beyond the basic building codes to improve overall building energy performance, optimize building ventilation, minimize life-cycle environmental impacts and make comfortable inside living environments. This paper briefly introduces the green design of the Lituo farmers market. Improving air quality inside of the built environment is the key for farmers market ventilation design as part of the green designs. The empirical method is used to design the height of the atrium of the farmers market to meet the ventilation requirements. A pressure loss model for outlet wire mesh screens was used for both empirical calculations and CFD. A simplified thermal boundary conditions for modeling human thermal effects were used to analyze the heat exchanges between the human body and the environment. The solar effects were only considered on the roof of the building. The outlet average exhaust gas speeds were measured and compared with CFD results. The results showed that the current method can help ventilation design and predicate the ventilation flow reasonably. The method developed in this study can be extended for other types of the building natural ventilation design and analysis.
{"title":"A farmers market architecture and ventilation design and its airflow analysis","authors":"Lei Chen, Chunhua Huang, Cheng Xu","doi":"10.1080/14733315.2021.1943923","DOIUrl":"https://doi.org/10.1080/14733315.2021.1943923","url":null,"abstract":"Abstract Green buildings and sustainable designs require architectural designers to go beyond the basic building codes to improve overall building energy performance, optimize building ventilation, minimize life-cycle environmental impacts and make comfortable inside living environments. This paper briefly introduces the green design of the Lituo farmers market. Improving air quality inside of the built environment is the key for farmers market ventilation design as part of the green designs. The empirical method is used to design the height of the atrium of the farmers market to meet the ventilation requirements. A pressure loss model for outlet wire mesh screens was used for both empirical calculations and CFD. A simplified thermal boundary conditions for modeling human thermal effects were used to analyze the heat exchanges between the human body and the environment. The solar effects were only considered on the roof of the building. The outlet average exhaust gas speeds were measured and compared with CFD results. The results showed that the current method can help ventilation design and predicate the ventilation flow reasonably. The method developed in this study can be extended for other types of the building natural ventilation design and analysis.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"41 1","pages":"3 - 23"},"PeriodicalIF":1.5,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86256872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Based on a case study of the undersea metro interval tunnel, this study proposes a model to evaluate the Ventilation and Smoke Exhaust System (VSES). In the VSES experiments, data of fan frequencies, powers, velocities, and static pressures in carriageways are collected, under the TPTE (Two Pressing-in fans + Two Extracted-out fans), the TPOEL (Two Pressing-in fans + One Extraction fan on the Left side of a smoke ceiling vent) and the TPOER (Two Pressing-in fans + One Extraction fan on the Right side of a smoke ceiling vent) combinations. The results show that the static pressures in both carriageways have fluctuation phenomena and symmetrical distributions, whose axis of symmetry is the smoke ceiling, regardless of combination type. These fluctuations have almost constant static pressures, which are associated with the increase in consumed powers while hardly compensate for the increase in volume flow rates. These rare compensations are essential to evaluate the effects of combinations on the relative shock loss. In order to quantify the differences, this study proposes a VSES performance and a deviation percentage model, and the results show that the TPTE resistance has the smallest shock losses of airflow going through the smoke ceiling vent.
{"title":"Experiments of combinational fans affecting smoke ceiling in an undersea metro interval tunnel VSES","authors":"Shi-qiang Chen, Siyu Fan, Ruohong Jin, Zhulong Zhu, Yihan Chen, Fangxing Chen, Haiqiao Wang","doi":"10.1080/14733315.2021.1943922","DOIUrl":"https://doi.org/10.1080/14733315.2021.1943922","url":null,"abstract":"Abstract Based on a case study of the undersea metro interval tunnel, this study proposes a model to evaluate the Ventilation and Smoke Exhaust System (VSES). In the VSES experiments, data of fan frequencies, powers, velocities, and static pressures in carriageways are collected, under the TPTE (Two Pressing-in fans + Two Extracted-out fans), the TPOEL (Two Pressing-in fans + One Extraction fan on the Left side of a smoke ceiling vent) and the TPOER (Two Pressing-in fans + One Extraction fan on the Right side of a smoke ceiling vent) combinations. The results show that the static pressures in both carriageways have fluctuation phenomena and symmetrical distributions, whose axis of symmetry is the smoke ceiling, regardless of combination type. These fluctuations have almost constant static pressures, which are associated with the increase in consumed powers while hardly compensate for the increase in volume flow rates. These rare compensations are essential to evaluate the effects of combinations on the relative shock loss. In order to quantify the differences, this study proposes a VSES performance and a deviation percentage model, and the results show that the TPTE resistance has the smallest shock losses of airflow going through the smoke ceiling vent.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"74 1","pages":"298 - 315"},"PeriodicalIF":1.5,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90965321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-28DOI: 10.1080/14733315.2021.1889104
W. Whyte, C. Mackintosh, W. Whyte
Abstract This article discusses the design of unidirectional airflow systems used to ventilate operating theatres and provide low concentrations of airborne micro-organisms during surgical operations. Also described are tests that can be used to confirm that unidirectional airflow systems are well designed and perform correctly when installed and during their lifetime. Reasons are given for the failure of unidirectional airflow systems to provide low concentrations of airborne micro-organisms and reduce joint infection rates after total joint arthroplasty when compared to conventional mixed-airflow operating theatres.
{"title":"The design and testing of unidirectional airflow operating theatres","authors":"W. Whyte, C. Mackintosh, W. Whyte","doi":"10.1080/14733315.2021.1889104","DOIUrl":"https://doi.org/10.1080/14733315.2021.1889104","url":null,"abstract":"Abstract This article discusses the design of unidirectional airflow systems used to ventilate operating theatres and provide low concentrations of airborne micro-organisms during surgical operations. Also described are tests that can be used to confirm that unidirectional airflow systems are well designed and perform correctly when installed and during their lifetime. Reasons are given for the failure of unidirectional airflow systems to provide low concentrations of airborne micro-organisms and reduce joint infection rates after total joint arthroplasty when compared to conventional mixed-airflow operating theatres.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"39 1","pages":"247 - 262"},"PeriodicalIF":1.5,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74736590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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