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A logic-based controller for the mitigation of ventilation air methane in a catalytic flow reversal reactor

Zhikai LI, Zhangfeng QIN, Yagang ZHANG, Zhiwei WU, Hui WANG, Shuna LI, Mei DONG, Weibin FAN, Jianguo WANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 347-356 doi: 10.1007/s11705-013-1347-0

摘要: The control system of a catalytic flow reversal reactor (CFRR) for the mitigation of ventilation air methane was investigated. A one-dimensional heterogeneous model with a logic-based controller was applied to simulate the CFRR. The simulation results indicated that the controller developed in this work performs well under normal conditions. Air dilution and auxiliary methane injection are effective to avoid the catalyst overheating and reaction extinction caused by prolonged rich and lean feed conditions, respectively. In contrast, the reactor is prone to lose control by adjusting the switching time solely. Air dilution exhibits the effects of two contradictory aspects on the operation of CFRR, i.e., cooling the bed and accumulating heat, though the former is in general more prominent. Lowering the reference temperature for flow reversal can decrease the bed temperature and benefit stable operation under rich methane feed condition.

关键词: ventilation air methane     reverse flow reactor     lean methane combustion     logic-based controller     mathematical modeling    

独头巷道空气年龄及通风有效性评价研究

王海桥,田峰,黄俊歆,陈涛

《中国工程科学》 2007年 第9卷 第11期   页码 43-47

摘要:

根据独头巷道作业空间的特点,给出了独头巷道局部空气年龄、平均空气年龄的定义及其计算模型,用示踪气体测定平均空气年龄的方法和原理,并用CFD (computational fluid dynamics)对独头巷道附壁受限射流通风流场及平均空气年龄进行了数值计算,得出了独头巷道空间通风流场和平均空气年龄分布,建立了计算换气效率和排污效率的数学模型。研究表明影响通风有效性的主要因素是空气年龄和污染物浓度,而影响空气年龄主要是通风气流组织和通风量。为评价独头巷道通风有效性提供了一种新的理论依据。

关键词: 独头巷道     平均空气年龄     通风有效性     换气效率     排污效率    

A concept of capillary active, dynamic insulation integrated with heating, cooling and ventilation, air

Mark BOMBERG

《结构与土木工程前沿(英文)》 2010年 第4卷 第4期   页码 431-437 doi: 10.1007/s11709-010-0071-9

摘要: When a historic fa?ade needs to be preserved or when the seismic considerations favor use of a concrete wall system and fire considerations limit exterior thermal insulation, one needs to use interior thermal insulation systems. Interior thermal insulation systems are less effective than the exterior systems and will not reduce the effect of thermal bridges. Yet they may be successfully used and, in many instances, are recommended as a complement to the exterior insulation. This paper presents one of these cases. It is focused on the most successful applications of capillary active, dynamic interior thermal insulation. This happens when such insulation is integrated with heating, cooling and ventilation, air conditioning (HVAC) system. Starting with a pioneering work of the Technical University in Dresden in development of capillary active interior insulations, we propose a next generation, namely, a bio-fiber thermal insulation. When completing the review, this paper proposes a concept of a joint research project to be undertaken by partners from the US (where improvement of indoor climate in exposed coastal areas is needed), China (indoor climate in non-air conditioned concrete buildings is an issue), and Germany (where the bio-fiber technology has been developed).

关键词: capillary active insulation     integrated heating     cooling and ventilation     air conditioning (HVAC) and building enclosure     dynamic insulation     switchable thermal resistance     variable U-value walls    

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION

《农业科学与工程前沿(英文)》 2023年 第10卷 第3期   页码 424-436 doi: 10.15302/J-FASE-2023506

摘要:

● Integration of alkaline pretreatment and air mixing for co-digestion was validated.

关键词: sodium hydroxide     air injection     cumulative methane yield     kinetic modeling analysis     digestate    

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

《能源前沿(英文)》 2019年 第13卷 第3期   页码 483-493 doi: 10.1007/s11708-019-0631-1

摘要: Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavy-duty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called pre-chamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a large-bore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides, as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词: marine engine     natural gas     methane     turbulent jet ignition (TJI)     pre-chamber    

适应性贴附通风——负压呼吸性传染病隔离病房有效性的比较研究 Article

张莹, 韩欧, 李安桂, 侯立安, Thomas Olofsson, 张林华, 雷文君

《工程(英文)》 2022年 第8卷 第1期   页码 130-137 doi: 10.1016/j.eng.2020.10.020

摘要:

新型冠状病毒的传播给隔离病房的室内环境控制提出了挑战。科学的气流组织设计和运行管理是保证医护人员环境安全的关键。本文提出了适应性贴附通风在隔离病房的应用,并从污染物扩散、去除效率、热舒适性和运行费用等方面对这种送风方式进行了评估。适应性贴附通风将新鲜空气直接、较好地供应至医护人员工作区。与顶送风或侧壁上送风相比,在相同的污染物释放率和房间换气次数(ACH; 10 h-1)条件下,适应性贴附通风的污染物平均浓度降低了15% ~ 47%。理想的混合通风的污染物去除效率不能超过1.0。对于适应性贴附通风,污染物去除效率是换气次数的指数函数。与顶送风模式或侧壁上送风模式相比,适应性贴附通风可实现相似的热舒适水平[预测平均评价(PMV)为-0.1~0.4;吹风感为2.5%~6.7%],且以较低的换气次数和能耗获得相似去除污染物的性能。

关键词: 通风效率     换气率     COVID-19     贴附通风     气流组织     隔离病房    

住宅厨房通风的数值分析

邹声华,李萍,翁培奋,罗一新

《中国工程科学》 2004年 第6卷 第12期   页码 69-72

摘要:

分析了我国现有的住宅厨房的通风方法,认为住宅厨房通风必须采用机械通风方法。将我国现有的住宅厨房通风方式分为三类,运用CFD分析方法,分别对它们的通风特性进行了分析,认为在建筑设计方面,只要布置好厨房的门、窗或排风口,就可获得较好的气流组织,有效排放厨房的污染物,提高厨房的空气质量。为我国住宅厨房通风设计提供了依据,为住宅建筑设计提供了思路。

关键词: 住宅厨房     通风方法     CFD     气流组织    

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

《能源前沿(英文)》 2013年 第7卷 第3期   页码 351-357 doi: 10.1007/s11708-013-0254-x

摘要: The zone model has been widely applied in control analysis of heating, ventilation and air conditioning (HVAC) systems to achieve a high building efficiency. This paper proposed a modified zone model which is much simpler in the HVAC system simulation and has the similar accuracy to the complicated simulation model. The proposed model took into consideration the effect of envelop heat reservoir on the room indoor temperature by introducing the thermal admittance of the inner surfaces of the building enclosure. The thermal admittance for the building enclosure was developed based on the building thermal network analytical theory and transfer function method. The efficacy of the proposed model was demonstrated by comparing it with the complicated model — heat balance method (HTB2 program). The predicted results from the proposed model well agreed with those from the complicated simulation. The proposed model can then make the HVAC system dynamic simulation much faster and more acceptable for control design due to its simplicity and efficiency.

关键词: room model     thermal network analysis     transfer function     heating     ventilation and air conditioning (HVAC) system simulation    

Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

Chuanjia JIANG, Pengyi ZHANG

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 184-194 doi: 10.1007/s11783-011-0309-3

摘要: Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1 μg·m , and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6 μg·m , respectively. Average indoor concentrations of other carbonyls were below 10 μg·m . Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbonyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become significant in the case of a large human occupancy.

关键词: carbonyl compounds     indoor air     ventilation     human occupancy     source emission rate (SER)     principal component analysis (PCA)    

Dissolved methane in anaerobic effluent: Emission or recovery?

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-022-1537-4

摘要: Various anaerobic processes have been explored for the energy-efficient treatment of municipal wastewater. However, dissolved methane in anaerobic effluent appears to be a barrier towards the energy and carbon neutrality of wastewater treatment. Although several dissolved methane recovery methods have been developed, their engineering feasibility and economic viability have not yet been assessed in a holistic manner. In this perspective, we thus intend to offer additional insights into the cost-benefit of dissolved methane recovery against its emission.

关键词: Anaerobic treatment     Municipal wastewater     Dissolved methane     Methane recovery     Carbon emission    

Full-scale site evaluation of ventilation expressway embankments underlain by warm permafrost along the

《结构与土木工程前沿(英文)》   页码 1047-1059 doi: 10.1007/s11709-023-0034-6

摘要: Ventilation embankments, including those with forced ventilation, natural ventilation, and combination of these, were adopted for the construction of the Gonghe−Yushu Expressway in warm permafrost areas. To evaluate the actual thermal performance of ventilation embankment in the Qinghai−Tibet Plateau, four types of ventilation embankments were selected as objects, and their long-term thermal characteristics were analyzed based on monitoring data. It was found that: 1) under the strong scale effect of a wide embankment, the crushed-rock embankment (CRE) was warming up and the permafrost table was declining year by year. Meanwhile, the combined ventilated slab and CRE and ventilated ducts embankment can effectively decrease the ground temperature and raise permafrost table in the year with a colder winter; 2) transverse temperature difference caused by the shady–sunny slope effect existed in all the four embankments. However, it was weakened by the combined ventilated slab and CRE and the ventilated ducts embankment due to their stronger cooling effect; and 3) the pre-existing embankment had a remarkable thermal disturbance to the adjacent newly-built embankment, so a reasonable embankment spacing should be considered in practical engineering. These findings would provide a reference for construction of expressway embankments in permafrost regions.

关键词: warm permafrost     expressway     ventilation embankments     temperature field    

终南山公路隧道非机械式通风效果研究

郑晅,郭佳奇

《中国工程科学》 2010年 第12卷 第3期   页码 39-44

摘要:

秦岭终南山特长公路隧道规模庞大,通风系统复杂,为了合理确定通风配置,节约通风费用,评估自然风和交通活塞风等非机械式通风方式的通风效果就显得非常重要。课题组现场监测了终南山特长公路隧道内的自然风速、交通量及自然风压和交通风压共同作用下的风速,收集了大量数据。通过对监测数据的处理、分析得出,较大自然风速出现在10∶00—14∶00这个时间段,最大自然风速达到2.576 m/s;隧道东、西线交通量出现高峰期的时间段基本恒定;隧道东线内自然风压和交通风压共同作用下的风速较大的时间段基本上与交通量高峰期时间段相吻合,而西线这两个时间段吻合性较差,洞内风速变化相对平缓。考虑洞口外风向频率、风向、洞口实测温度等参数的自然风速计算方法计算值与实测自然风速较接近。隧道内自然风压和交通风压联合作用下的风速计算值虽小于现场实测值,但较接近实测值。

关键词: 隧道通风     现场监测     非机械式通风     自然风     交通活塞风    

Prevention of surgical site infection under different ventilation systems in operating room environment

Zhijian Liu, Haiyang Liu, Hang Yin, Rui Rong, Guoqing Cao, Qihong Deng

《环境科学与工程前沿(英文)》 2021年 第15卷 第3期 doi: 10.1007/s11783-020-1327-9

摘要: Abstract • The effectiveness of four different ventilation systems was compared in depth. • Airflow and bacteria-carrying particles concentration were quantitatively analyzed. • Vertical laminar airflow with high airflow rate could not achieve desired effect. • Temperature-controlled airflow ventilation could guarantee air cleanliness. Biological particles in the operating room (OR) air environment can cause surgical site infections (SSIs). Various ventilation systems have been employed in ORs to ensure an ultraclean environment. However, the effect of different ventilation systems on the control of bacteria-carrying particles (BCPs) released from the surgical staff during surgery is unclear. In this study, the performance of four different ventilation systems (vertical laminar airflow ventilation (VLAF), horizontal laminar airflow ventilation (HLAF), differential vertical airflow ventilation (DVAF), and temperature-controlled airflow ventilation (TAF)) used in an OR was evaluated and compared based on the spatial BCP concentration. The airflow field in the OR was solved by the Renormalization Group (RNG) k-e turbulence model, and the BCP phase was calculated by Lagrangian particle tracking (LPT) and the discrete random walk (DRW) model. It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area. This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution, which was greatly affected by obstacles such as surgical lamps and surgical staff.

关键词: Operating room (OR)     Bacteria-carrying particles (BCPs)     Surgical site infections (SSIs)     Ventilation    

USING NUTRITIONAL STRATEGIES TO MITIGATE RUMINAL METHANE EMISSIONS FROM RUMINANTS

《农业科学与工程前沿(英文)》 2023年 第10卷 第3期   页码 390-402 doi: 10.15302/J-FASE-2023504

摘要:

● Microbial fermentation in the rumen is a main source of methane emissions.

关键词: nutritional strategy     mitigation     microbe     methane     ruminant    

整合矿井复杂通风系统的优化改造

张付涛

《中国工程科学》 2011年 第13卷 第11期   页码 68-71

摘要:

唐山沟煤矿作为资源整合矿井,存在通风系统复杂和安全隐患多等一系列问题,通过通风阻力测定、风机性能测试和通风系统合理可靠性评价,查找原有矿井通风系统存在的问题,分析其主要原因,提出了通风系统优化改造方案。经实施后,降低了通风系统阻力,提高了矿井通风系统稳定性和抗灾能力。

关键词: 整合矿井     复杂通风系统     优化改造    

标题 作者 时间 类型 操作

A logic-based controller for the mitigation of ventilation air methane in a catalytic flow reversal reactor

Zhikai LI, Zhangfeng QIN, Yagang ZHANG, Zhiwei WU, Hui WANG, Shuna LI, Mei DONG, Weibin FAN, Jianguo WANG

期刊论文

独头巷道空气年龄及通风有效性评价研究

王海桥,田峰,黄俊歆,陈涛

期刊论文

A concept of capillary active, dynamic insulation integrated with heating, cooling and ventilation, air

Mark BOMBERG

期刊论文

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION

期刊论文

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constantvolume chamber: effect of air-fuel equivalence ratio and pre-mixed pressure

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

期刊论文

适应性贴附通风——负压呼吸性传染病隔离病房有效性的比较研究

张莹, 韩欧, 李安桂, 侯立安, Thomas Olofsson, 张林华, 雷文君

期刊论文

住宅厨房通风的数值分析

邹声华,李萍,翁培奋,罗一新

期刊论文

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

期刊论文

Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

Chuanjia JIANG, Pengyi ZHANG

期刊论文

Dissolved methane in anaerobic effluent: Emission or recovery?

期刊论文

Full-scale site evaluation of ventilation expressway embankments underlain by warm permafrost along the

期刊论文

终南山公路隧道非机械式通风效果研究

郑晅,郭佳奇

期刊论文

Prevention of surgical site infection under different ventilation systems in operating room environment

Zhijian Liu, Haiyang Liu, Hang Yin, Rui Rong, Guoqing Cao, Qihong Deng

期刊论文

USING NUTRITIONAL STRATEGIES TO MITIGATE RUMINAL METHANE EMISSIONS FROM RUMINANTS

期刊论文

整合矿井复杂通风系统的优化改造

张付涛

期刊论文