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":"70 1","pages":"284 - 297"},"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":"51 1","pages":"287 - 294"},"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":"16 1","pages":"1 - 18"},"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":"60 1","pages":"263 - 283"},"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":"26 1","pages":"213 - 228"},"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":"42 1","pages":"53 - 73"},"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":"14 1","pages":"74 - 87"},"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}
Pub Date : 2021-01-27DOI: 10.1080/14733315.2020.1864572
Haruna Yamasawa, Tomohiro Kobayashi, T. Yamanaka, N. Choi, M. Matsuzaki
Abstract The impinging jet ventilation (IJV) system has been proposed as a new air distribution strategy and is expected to overcome the disadvantages of mixing ventilation (MV) system, which is the most widely used system, and displacement ventilation (DV), which provides better air quality than MV. The aim of this study is to accumulate the fundamental feature of IJV and to propose a simple method to predict the indoor environment with IJV. Full-scale experiments were conducted in a climate chamber, in order to investigate the features of IJV. Different ventilation systems and supply air conditions were investigated along with indoor thermal environments, and ventilation effectiveness. For IJV, the indoor environment was similar to that of DV with small supply momentum, and was similar to that of MV with large supply momentum. The specific Archimedes number, which can be calculated by design conditions, was defined to express the balance between the supply momentum and buoyancy force. The correlation between the Archimedes number and indices for thermal environment and ventilation effectiveness are finally shown as prediction method.
{"title":"Experimental investigation of difference in indoor environment using impinging jet ventilation and displacement ventilation systems","authors":"Haruna Yamasawa, Tomohiro Kobayashi, T. Yamanaka, N. Choi, M. Matsuzaki","doi":"10.1080/14733315.2020.1864572","DOIUrl":"https://doi.org/10.1080/14733315.2020.1864572","url":null,"abstract":"Abstract The impinging jet ventilation (IJV) system has been proposed as a new air distribution strategy and is expected to overcome the disadvantages of mixing ventilation (MV) system, which is the most widely used system, and displacement ventilation (DV), which provides better air quality than MV. The aim of this study is to accumulate the fundamental feature of IJV and to propose a simple method to predict the indoor environment with IJV. Full-scale experiments were conducted in a climate chamber, in order to investigate the features of IJV. Different ventilation systems and supply air conditions were investigated along with indoor thermal environments, and ventilation effectiveness. For IJV, the indoor environment was similar to that of DV with small supply momentum, and was similar to that of MV with large supply momentum. The specific Archimedes number, which can be calculated by design conditions, was defined to express the balance between the supply momentum and buoyancy force. The correlation between the Archimedes number and indices for thermal environment and ventilation effectiveness are finally shown as prediction method.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"29 1","pages":"229 - 246"},"PeriodicalIF":1.5,"publicationDate":"2021-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84169839","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 : 2021-01-02DOI: 10.1080/14733315.2019.1698164
P. Weisenpacher, L. Valásek
Abstract In this paper the FDS 6 code ability to simulate the airflows generated by jet fans in a real road tunnel is studied. A transient model of the 898 m long bi-directional highway Polana tunnel is created including details of the tunnel geometry as emergency lay-bys and traffic signs. The absolute roughness of the tunnel walls of 70 mm is determined to represent the influence of curved tunnel geometry and tunnel equipment not explicitly modelled on the tunnel airflows and their retardation. The simulations results are compared against on-site measurements during a full-scale ventilation test conducted in the Polana tunnel in 2017. The comparison includes steady-state bulk airflow velocity and velocity profile investigated by a grid of five anemometers. The simulations results are in good accordance with experimental data with relative errors below 2% for bulk velocities and typically below 9% for velocities measured by particular grid anemometers. Specific circumstances where errors exceed the latter value are discussed. The influence of unknown external dynamic pressure fluctuations on the simulation results is also analysed. Optimal settings for parallel computations are determined from the point of view of simulation accuracy and performance. The model is intended for purposes of tunnel fires modelling.
{"title":"Computer simulation of airflows generated by jet fans in real road tunnel by parallel version of FDS 6","authors":"P. Weisenpacher, L. Valásek","doi":"10.1080/14733315.2019.1698164","DOIUrl":"https://doi.org/10.1080/14733315.2019.1698164","url":null,"abstract":"Abstract In this paper the FDS 6 code ability to simulate the airflows generated by jet fans in a real road tunnel is studied. A transient model of the 898 m long bi-directional highway Polana tunnel is created including details of the tunnel geometry as emergency lay-bys and traffic signs. The absolute roughness of the tunnel walls of 70 mm is determined to represent the influence of curved tunnel geometry and tunnel equipment not explicitly modelled on the tunnel airflows and their retardation. The simulations results are compared against on-site measurements during a full-scale ventilation test conducted in the Polana tunnel in 2017. The comparison includes steady-state bulk airflow velocity and velocity profile investigated by a grid of five anemometers. The simulations results are in good accordance with experimental data with relative errors below 2% for bulk velocities and typically below 9% for velocities measured by particular grid anemometers. Specific circumstances where errors exceed the latter value are discussed. The influence of unknown external dynamic pressure fluctuations on the simulation results is also analysed. Optimal settings for parallel computations are determined from the point of view of simulation accuracy and performance. The model is intended for purposes of tunnel fires modelling.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"102 1","pages":"20 - 33"},"PeriodicalIF":1.5,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91225260","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 : 2020-12-22DOI: 10.1080/14733315.2020.1859058
Liying Sun, Yifan Jiang
Abstract Few of existing literatures on the airflow distribution of compartments have studied combined applications of radiant heating and air conditioning in winter. Simulation of airflow distribution in 25 T soft sleeper compartments under different heating and ventilation schemes is provided in this paper. Firstly, reliability of the numerical simulation model has been verified by the experimental data in the literature, and the appropriate turbulence model has been selected. Afterwards, numerical simulations are carried out on airflow distribution in those compartments with four ventilation modes under radiant heating conditions in winter. Research results show that as for thermal comfort, task air supply can provide the smallest temperature difference between head and foot positions as well as the best thermal comfort. As for effectiveness of air supply, the ventilation efficiency of louver side air supply is the highest among others. As for effectiveness of pollutant removal, the ventilation efficiency of task air supply is higher than the other three options. These four heating and ventilation schemes are evaluated comprehensively with fuzzy comprehensive evaluation method. Results reveal that task air supply is the mode with best comprehensive performance indices. It is followed, respectively, by louver side air supply, perforated ceiling air supply and louver top air supply.
{"title":"Effect of air supply mode on airflow distribution in winter train sleeper compartments","authors":"Liying Sun, Yifan Jiang","doi":"10.1080/14733315.2020.1859058","DOIUrl":"https://doi.org/10.1080/14733315.2020.1859058","url":null,"abstract":"Abstract Few of existing literatures on the airflow distribution of compartments have studied combined applications of radiant heating and air conditioning in winter. Simulation of airflow distribution in 25 T soft sleeper compartments under different heating and ventilation schemes is provided in this paper. Firstly, reliability of the numerical simulation model has been verified by the experimental data in the literature, and the appropriate turbulence model has been selected. Afterwards, numerical simulations are carried out on airflow distribution in those compartments with four ventilation modes under radiant heating conditions in winter. Research results show that as for thermal comfort, task air supply can provide the smallest temperature difference between head and foot positions as well as the best thermal comfort. As for effectiveness of air supply, the ventilation efficiency of louver side air supply is the highest among others. As for effectiveness of pollutant removal, the ventilation efficiency of task air supply is higher than the other three options. These four heating and ventilation schemes are evaluated comprehensively with fuzzy comprehensive evaluation method. Results reveal that task air supply is the mode with best comprehensive performance indices. It is followed, respectively, by louver side air supply, perforated ceiling air supply and louver top air supply.","PeriodicalId":55613,"journal":{"name":"International Journal of Ventilation","volume":"23 4 1","pages":"122 - 139"},"PeriodicalIF":1.5,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89386313","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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