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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
Pub Date : 2021-04-27DOI: 10.1080/14733315.2021.1914917
Liandong Dong, Ke Zhang, Zhen Qian
Abstract The main aim of this study is to predict the temperature characteristics in large-span manufacture area of clean room using the Computational Fluid Dynamics (CFD). The CFD model was established based on a large semiconductor plant and verified by measured data. Then, the effects of these factors including fan filter unit (FFU) configuration, building envelope and fresh air system on temperature distribution were analyzed. The results indicate that both increasing FFU air velocity and placement rate can decrease maximum temperature difference. The 33% placement rate has a higher performance-price ratio because the maximum temperature difference differs slightly at 33% and 50% placement rates. The number of FFU can decrease by 415 when placement rate reduces from 50% to 33%. Increasing the thermal resistance of building envelope can also improve the temperature distribution. And changing the thermal insulation properties of roof is more effective than changing that of external wall. So, more attention should be paid to the thermal insulation properties of roof. For fresh air system, fresh air needs to mix well with original air to reduce the effect on temperature. Thus, fresh air inlet port should be inserted into the return air plenum in the design.
{"title":"The investigation of air temperature characteristics in large-span manufacture area of clean room","authors":"Liandong Dong, Ke Zhang, Zhen Qian","doi":"10.1080/14733315.2021.1914917","DOIUrl":"https://doi.org/10.1080/14733315.2021.1914917","url":null,"abstract":"Abstract The main aim of this study is to predict the temperature characteristics in large-span manufacture area of clean room using the Computational Fluid Dynamics (CFD). The CFD model was established based on a large semiconductor plant and verified by measured data. Then, the effects of these factors including fan filter unit (FFU) configuration, building envelope and fresh air system on temperature distribution were analyzed. The results indicate that both increasing FFU air velocity and placement rate can decrease maximum temperature difference. The 33% placement rate has a higher performance-price ratio because the maximum temperature difference differs slightly at 33% and 50% placement rates. The number of FFU can decrease by 415 when placement rate reduces from 50% to 33%. Increasing the thermal resistance of building envelope can also improve the temperature distribution. And changing the thermal insulation properties of roof is more effective than changing that of external wall. So, more attention should be paid to the thermal insulation properties of roof. For fresh air system, fresh air needs to mix well with original air to reduce the effect on temperature. Thus, fresh air inlet port should be inserted into the return air plenum in the design.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73525191","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 : 2021-04-02DOI: 10.1080/14733315.2020.1777661
T. Lanooy, N. Bink, W. Kornaat, W. Borsboom
Abstract The building airtightness is essential to achieve a high energy performance. In most countries however, it is not mandatory to measure the airtightness. In the Netherlands it is common practice to just take several samples in a housing project. These samples do not give a good indication for all the buildings in a project. It is therefore important to measure the airtightness of all the buildings. Current methods for airtightness measuring are too expensive and time consuming to make this feasible. A method with a new device, the AirTightnessTester (ATT), is proposed. By using the buildings ventilation system, a reduction in price and time can be achieved. The ATT measures in compliance with RESNET-380-2016. The ATT makes use of the ventilation system of the building. It will be explained when and how the ATT makes use of a ventilation system. We have looked at the different ventilation systems that are commonly used in new housing projects in somewhat more detail to analyse the feasibility of our method in practice. It is concluded that several systems can be used as they are now. Some ventilation systems cannot be turned on and off easily. For these ventilation systems a setting switching method has been developed. The theory behind this method, and some preliminary results using this method will be presented. To validate measurements with the ATT, comparisons have been done to the blower door. Preliminary results were already presented during the 2018 AIVC conference but further validation was still necessary. The measurements with the blower door are multi-point measurements and are all done in compliance with ISO9972. The measurements done with the ATT are all single-point measurements. The comparisons are made with the blower door, because since it is the most used method for airtightness measuring. To get a fair comparison, the uncertainty of both methods is taken into account. Overall the blower door and the ATT give show similar results for the airtigthness. In 23 of the 37 measurements it was found that the measured air leakage with the ATT was slightly higher than the measurement compared to the result with the blower door. When switching between a low and a high flow, it was found that 10 out of 12 measurements with the ATT were higher.
{"title":"Applicability of a simple and new airtightness measuring method and further comparisons with blower door measurements","authors":"T. Lanooy, N. Bink, W. Kornaat, W. Borsboom","doi":"10.1080/14733315.2020.1777661","DOIUrl":"https://doi.org/10.1080/14733315.2020.1777661","url":null,"abstract":"Abstract The building airtightness is essential to achieve a high energy performance. In most countries however, it is not mandatory to measure the airtightness. In the Netherlands it is common practice to just take several samples in a housing project. These samples do not give a good indication for all the buildings in a project. It is therefore important to measure the airtightness of all the buildings. Current methods for airtightness measuring are too expensive and time consuming to make this feasible. A method with a new device, the AirTightnessTester (ATT), is proposed. By using the buildings ventilation system, a reduction in price and time can be achieved. The ATT measures in compliance with RESNET-380-2016. The ATT makes use of the ventilation system of the building. It will be explained when and how the ATT makes use of a ventilation system. We have looked at the different ventilation systems that are commonly used in new housing projects in somewhat more detail to analyse the feasibility of our method in practice. It is concluded that several systems can be used as they are now. Some ventilation systems cannot be turned on and off easily. For these ventilation systems a setting switching method has been developed. The theory behind this method, and some preliminary results using this method will be presented. To validate measurements with the ATT, comparisons have been done to the blower door. Preliminary results were already presented during the 2018 AIVC conference but further validation was still necessary. The measurements with the blower door are multi-point measurements and are all done in compliance with ISO9972. The measurements done with the ATT are all single-point measurements. The comparisons are made with the blower door, because since it is the most used method for airtightness measuring. To get a fair comparison, the uncertainty of both methods is taken into account. Overall the blower door and the ATT give show similar results for the airtigthness. In 23 of the 37 measurements it was found that the measured air leakage with the ATT was slightly higher than the measurement compared to the result with the blower door. When switching between a low and a high flow, it was found that 10 out of 12 measurements with the ATT were higher.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87627335","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 : 2021-03-25DOI: 10.1080/14733315.2021.1876406
Yicun Hou, Angui Li, Sen Mei
Abstract A traditional residence is not only a symbol of historic wisdom, but also represents the development of superior building experience. The weather in regions south of the Yangtze River is wet and hot; therefore, the local people have taken many effective measures to improve their indoor environment, such as the reasonable layout of windows, the effect of double pitch roofs and the effect of patio. This paper studied such natural ventilation measures, learning ventilation enhancement techniques from Chinese traditional architecture. The paper takes both a Chinese traditional architecture Shangzhi Tang and a typical modern building as research objects. A detailed field test was conducted and a series of evaluation indexes such as indoor and outdoor air temperature, relative humidity, and air velocities have been analysed. In addition, CFD (Computational Fluid Dynamics) software was utilized to simulate the air distribution for both building types.
{"title":"Learning from Chinese traditional architecture: field test and CFD modelling of ventilation enhancement techniques in southern Chinese houses","authors":"Yicun Hou, Angui Li, Sen Mei","doi":"10.1080/14733315.2021.1876406","DOIUrl":"https://doi.org/10.1080/14733315.2021.1876406","url":null,"abstract":"Abstract A traditional residence is not only a symbol of historic wisdom, but also represents the development of superior building experience. The weather in regions south of the Yangtze River is wet and hot; therefore, the local people have taken many effective measures to improve their indoor environment, such as the reasonable layout of windows, the effect of double pitch roofs and the effect of patio. This paper studied such natural ventilation measures, learning ventilation enhancement techniques from Chinese traditional architecture. The paper takes both a Chinese traditional architecture Shangzhi Tang and a typical modern building as research objects. A detailed field test was conducted and a series of evaluation indexes such as indoor and outdoor air temperature, relative humidity, and air velocities have been analysed. In addition, CFD (Computational Fluid Dynamics) software was utilized to simulate the air distribution for both building types.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81970467","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 : 2021-03-22DOI: 10.1080/14733315.2021.1901003
M. Sharma, Sajan Preet, Jyotirmay Mathur, A. Chowdhury, S. Mathur
Abstract A new skin of perforated sheets in the cavity of double skin facades (DSF) system is introduced for efficient heat removal from the cavity in hot summer conditions. In this paper, the analytical solution is developed to estimate the thermal performance of the double-skin façade system with and without perforated sheet operating under natural ventilation mode. This analytical model is designed to predict the solar heat gain coefficient (SHGC) for hot summer conditions. An experimental investigation has also been conducted to validate the proposed analytical model. Results showed good agreement between the measured and calculated value of SHGC for DSF system with and without perforated sheet. It is observed that the addition of a perforated sheet reduces the SHGC by nearly 51.5% as compared to DSF system. Perforated sheets enable a better stack effect within the air cavity zone and thereby improve heat transfer characteristics. Therefore, the benefit of the perforated sheet within the air cavity of DSF system is profound over conventional DSF system.
{"title":"Thermal performance analysis of naturally ventilated and perforated sheet based double skin facade system for hot summer conditions","authors":"M. Sharma, Sajan Preet, Jyotirmay Mathur, A. Chowdhury, S. Mathur","doi":"10.1080/14733315.2021.1901003","DOIUrl":"https://doi.org/10.1080/14733315.2021.1901003","url":null,"abstract":"Abstract A new skin of perforated sheets in the cavity of double skin facades (DSF) system is introduced for efficient heat removal from the cavity in hot summer conditions. In this paper, the analytical solution is developed to estimate the thermal performance of the double-skin façade system with and without perforated sheet operating under natural ventilation mode. This analytical model is designed to predict the solar heat gain coefficient (SHGC) for hot summer conditions. An experimental investigation has also been conducted to validate the proposed analytical model. Results showed good agreement between the measured and calculated value of SHGC for DSF system with and without perforated sheet. It is observed that the addition of a perforated sheet reduces the SHGC by nearly 51.5% as compared to DSF system. Perforated sheets enable a better stack effect within the air cavity zone and thereby improve heat transfer characteristics. Therefore, the benefit of the perforated sheet within the air cavity of DSF system is profound over conventional DSF system.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85863601","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 : 2021-03-01DOI: 10.1080/14733315.2020.1861774
Valeria Hofer, A. Hartmann, Hansjörg Rotheudt, Benjamin Zielke, M. Kriegel
Abstract In operating rooms with unidirectional air flow a wake is formed below the light. The influence of the geometry on the dimension of the wake and the age of air were investigated by means of validated numerical simulations as well as experimental measurements. The vertical dimension of the wake caused by the circular surgical light was 1.08 m in height. With an air-permeable shape, it could be reduced to 0.38 m (brim) to 0.28 m (centre). A more open design increased the dilution within the recirculating area and resulted in a shorter residence time of contaminants.
{"title":"Disturbance of a laminar air flow caused by differently shaped surgical lights","authors":"Valeria Hofer, A. Hartmann, Hansjörg Rotheudt, Benjamin Zielke, M. Kriegel","doi":"10.1080/14733315.2020.1861774","DOIUrl":"https://doi.org/10.1080/14733315.2020.1861774","url":null,"abstract":"Abstract In operating rooms with unidirectional air flow a wake is formed below the light. The influence of the geometry on the dimension of the wake and the age of air were investigated by means of validated numerical simulations as well as experimental measurements. The vertical dimension of the wake caused by the circular surgical light was 1.08 m in height. With an air-permeable shape, it could be reduced to 0.38 m (brim) to 0.28 m (centre). A more open design increased the dilution within the recirculating area and resulted in a shorter residence time of contaminants.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74676471","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 : 2021-02-07DOI: 10.1080/14733315.2021.1876407
Li Zhu, Zhilei Wang, Xuhai Pan, Xinxin Guo, M. Hua, Juncheng Jiang
Abstract With the modernization of urban development, land resources are becoming increasingly scarce. A new type of building model comprising an underground depot and a superstructure has been constructed. To study the hybrid ventilation (HV) in interlayer of the underground depot with a superstructure under monorail line section fire, full-scale numerical simulation and reduced-scale (1:50) experiment were performed. Five ventilation velocities were used under a certain heat release rate. The temperature distribution and stratification in the interlayer were examined, and the movement of the fire smoke was analyzed. The smoke layer was visualized using a laser sheet and the smoke layer thickness determined by N-percentage rule (N = 10, 20, 30) was compared with the results of visual observation. At the same time, CFD simulations were conducted to measure the height of smoke layer and the smoke front propagation. Besides, the distribution of carbon monoxide (CO) in the interlayer was also simulated. The results show that N value of 30 could properly determine the smoke layer thickness in relatively stable stage of combustion. HV had a better effect on smoke control than natural ventilation (NV) did. At a ventilation velocity of 1.4 m/s, the smoke layer in the interlayer remained in a steady state until its exclusion from the building. CO could be effectively controlled and did not spread all over the interlayer in HV systems. The structure of HV system can be adjusted according to the actual conditions of the various sizes and types of buildings. Thus, the HV system shows good adaptability and can be directly applied to the design and installation of new buildings such as underground garages and depots. The results of the fire dynamic simulations and experimental tests exhibited considerable agreement.
{"title":"Experimental and simulation studies on hybrid ventilation in interlayer of underground depot with superstructure","authors":"Li Zhu, Zhilei Wang, Xuhai Pan, Xinxin Guo, M. Hua, Juncheng Jiang","doi":"10.1080/14733315.2021.1876407","DOIUrl":"https://doi.org/10.1080/14733315.2021.1876407","url":null,"abstract":"Abstract With the modernization of urban development, land resources are becoming increasingly scarce. A new type of building model comprising an underground depot and a superstructure has been constructed. To study the hybrid ventilation (HV) in interlayer of the underground depot with a superstructure under monorail line section fire, full-scale numerical simulation and reduced-scale (1:50) experiment were performed. Five ventilation velocities were used under a certain heat release rate. The temperature distribution and stratification in the interlayer were examined, and the movement of the fire smoke was analyzed. The smoke layer was visualized using a laser sheet and the smoke layer thickness determined by N-percentage rule (N = 10, 20, 30) was compared with the results of visual observation. At the same time, CFD simulations were conducted to measure the height of smoke layer and the smoke front propagation. Besides, the distribution of carbon monoxide (CO) in the interlayer was also simulated. The results show that N value of 30 could properly determine the smoke layer thickness in relatively stable stage of combustion. HV had a better effect on smoke control than natural ventilation (NV) did. At a ventilation velocity of 1.4 m/s, the smoke layer in the interlayer remained in a steady state until its exclusion from the building. CO could be effectively controlled and did not spread all over the interlayer in HV systems. The structure of HV system can be adjusted according to the actual conditions of the various sizes and types of buildings. Thus, the HV system shows good adaptability and can be directly applied to the design and installation of new buildings such as underground garages and depots. The results of the fire dynamic simulations and experimental tests exhibited considerable agreement.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80730459","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 : 2021-02-01DOI: 10.1080/14733315.2021.1876408
Athmane Gheziel, S. Hanini, Brahim Mohamedi
Abstract Due to experimental data insufficiency for results validation realized by Computation Fluid Dynamics method (CFD), we are proposed new numerical simulations to determined concentration distribution of fine particles in indoor air for transient regime. The ANN model approach of multi-layer perceptron type with three layers is applied successfully. This model requires learning through a database which deduced from the bibliographic literature, composed by 2271 measurement points of which 80% assigned to ANN model training, 10% to test model and so the remaining (10%) assigned to validation part. The ANN model developed in this paper is beneficial and easy to predict fine particles distribution in air indoor when compared to the CFD method. The results average error found by this model does not reach 5%, when compared to the CFD method with an error of 16%. This model is used to treat the effect of the velocity and air exhaust section positions on the stability and flow regime establishment time.
{"title":"Artificial neural network (ANN) for prediction indoor airborne particle concentration","authors":"Athmane Gheziel, S. Hanini, Brahim Mohamedi","doi":"10.1080/14733315.2021.1876408","DOIUrl":"https://doi.org/10.1080/14733315.2021.1876408","url":null,"abstract":"Abstract Due to experimental data insufficiency for results validation realized by Computation Fluid Dynamics method (CFD), we are proposed new numerical simulations to determined concentration distribution of fine particles in indoor air for transient regime. The ANN model approach of multi-layer perceptron type with three layers is applied successfully. This model requires learning through a database which deduced from the bibliographic literature, composed by 2271 measurement points of which 80% assigned to ANN model training, 10% to test model and so the remaining (10%) assigned to validation part. The ANN model developed in this paper is beneficial and easy to predict fine particles distribution in air indoor when compared to the CFD method. The results average error found by this model does not reach 5%, when compared to the CFD method with an error of 16%. This model is used to treat the effect of the velocity and air exhaust section positions on the stability and flow regime establishment time.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86715281","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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