Effects of Indoor Ventilation and Air Mixing on Disinfection Efficacy of Upper-Room UVGI System

2014 ◽  
Author(s):  
W. Cai ◽  
G. Pitchurov ◽  
J. Srebric ◽  
F.Y. Gao ◽  
S.W. Zhu
Keyword(s):  
Air Mixing ◽  
Upper Room

ПРОДУКТИВНОСТЬ ЦЫПЛЯТ-БРОЙЛЕРОВ ПРИ ИСПОЛЬЗОВАНИИ УЛЬТРАФИОЛЕТОВЫХ АМАЛЬГАМНЫХ ЛАМП ДЛЯ ОБЕЗЗАРАЖИВАНИЯ ВОЗДУХА

2019 ◽  
Keyword(s):  
Upper Room

ЖУРАВЧУК Е.В. Федеральный научный центр «Всероссийский научно-исследовательский и технологический институт птицеводства» Российской академии наук Аннотация: В статье представлены результаты опыта по обеззараживанию воздуха в птичнике ультрафиолетовым (УФ) облучением в присутствии птицы. Для проведения опыта было сформировано две группы цыплят-бройлеров (по 200 голов), которых выращивали на подстилке до 36 дней жизни. В опытной группе использовался открытый УФ-облучатель мощностью 300 Вт с бактерицидной безозоновой амальгамной лампой. Санация воздуха проводилась в прерывистом режиме, увязанном с режимом освещения, методом непрямого облучения (upper-room). Результаты исследований показали, что обеззараживание воздуха путем УФ-облучения бактерицидной амальгамной лампой оказало положительное воздействие на продуктивные показатели бройлеров. Средняя живая масса цыплят опытной группы была достоверно выше, чем в контрольной, на 3,4% (р<0,05). Затраты корма на 1 кг прироста живой массы в опытной группе были на 2,3% ниже, чем в контроле. По сохранности поголовья опытная группа превзошла контроль на 1,5%. Также было установлено, что снижение микробной нагрузки на организм цыплят опытной группы способствовало повышению эффективности иммунизации птицы против вируса болезни Ньюкасла. Ключевые слова: ПТИЦЕВОДСТВО, ВОЗДУШНАЯ СРЕДА, МИКРООРГАНИЗМЫ, ОБЕЗЗАРАЖИВАЮЩЕЕ УФ-ИЗЛУЧЕНИЕ, АМАЛЬГАМНЫЕ УФ-ЛАМПЫ, ПРОДУКТИВНОСТЬ,

Numerical Analysis on the CO-NO Formation Production near Burner Throat in Swirling Flow Combustion System

2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Mohamad Shaiful Ashrul Ishak ◽  
Mohammad Nazri Mohd Jaafar
Keyword(s):  
Swirling Flow ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Recirculation Region ◽  
Mixing Enhancement ◽  
Ansys Fluent ◽  
Pressure Losses ◽  
No Formation ◽  
Swirl Angle ◽  
Air Mixing

The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on CO-NO formation production inside the combustor close to burner throat while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length has been investigated. Analysis were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was investigated numerically using CFD solver Ansys Fluent. This study has provided characteristic insight into the formation and production of CO and pollutant NO inside the combustion chamber. Results show that the swirling action is augmented with the increase in the swirl angle, which leads to increase in the center core reverse flow, therefore reducing the CO and pollutant NO formation. The outcome of this work will help in finding out the optimum swirling angle which will lead to less emission.  

scholarly journals Jet A and Propane gas combustion in a turboshaft engine: performance and emissions reductions

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Ali Hasan ◽  
Oskar J. Haidn
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Emissions Reductions ◽  
Gas Combustion ◽  
Liquid Petroleum Gas ◽  
Performance And Emissions ◽  
Air Mixing ◽  
Turboshaft Engine ◽  
Engine Performance And Emissions ◽  
Lower Carbon

AbstractThe Paris Agreement has highlighted the need in reducing carbon emissions. Attempts in using lower carbon fuels such as Propane gas have seen limited success, mainly due to liquid petroleum gas tanks structural/size limitations. A compromised solution is presented, by combusting Jet A fuel with a small fraction of Propane gas. Propane gas with its relatively faster overall igniting time, expedites the combustion process. Computational fluid dynamics software was used to demonstrate this solution, with results validated against physical engine data. Jet A fuel was combusted with different Propane gas dosing fractions. Results demonstrated that depending on specific propane gas dosing fractions emission reductions in ppm are; NOx from 84 to 41, CO2 from less than 18,372 to less than 15,865, escaping unburned fuels dropped from 11.4 (just Jet A) to 6.26e-2 (with a 0.2 fraction of Propane gas). Soot and CO increased, this is due to current combustion chamber air mixing design.

An alternative approach to evaluate fuel/air mixing quality

2021 ◽  
pp. 1-15
Author(s):  
L.-Y. Jiang
Keyword(s):  
Temperature Variation ◽  
Practical Method ◽  
Maximum Temperature ◽  
Air Distribution ◽  
Ratio Distribution ◽  
Alternative Approach ◽  
Low Emission ◽  
Mixing Quality ◽  
Mixer Design ◽  
Air Mixing

ABSTRACT A practical method to evaluate quantitatively the uniformity of fuel/air mixing is essential for research and development of advanced low-emission combustion systems. Typically, this is characterised by measuring an unmixedness parameter or a uniformity index. An alternative approach, based on the fuel/air equivalence ratio distribution, is proposed and demonstrated in a simple methane/air venturi mixer. This approach has two main advantages: it is correlated with the fuel/air mixture combustion temperature, and the maximum temperature variation caused by fuel/air non-uniformity can be estimated. Because of these, it can be used as a criterion to check fuel/air mixing quality, or as a target for fuel/air mixer design with acceptable maximum temperature variation. For the situations where the fuel/air distribution non-uniqueness issue becomes important for fuel/air mixing check or mixer design, an additional statistical supplementary criterion should also be used.

scholarly journals Indoor Airflow Distribution in Repository Design: Experimental and Numerical Microclimate Analysis of an Archive

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 152
Author(s):  
Karin Kompatscher ◽  
Rick P. Kramer ◽  
Bart Ankersmit ◽  
Henk L. Schellen
Keyword(s):  
Vertical Gradient ◽  
Building Envelope ◽  
Cfd Modeling ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Climate Control ◽  
Climate Conditions ◽  
Airflow Distribution ◽  
Air Mixing ◽  
Delay Variations

The majority of cultural heritage is stored in archives, libraries and museum storage spaces. To reduce degradation risks, many archives adopt the use of archival boxes, among other means, to provide the necessary climate control and comply with strict legislation requirements regarding temperature and relative air humidity. A strict ambient indoor climate is assumed to provide adequate environmental conditions near objects. Guidelines and legislation provide requirements for ambient indoor climate parameters, but often do not consider other factors that influence the near-object environment, such as the use of archival boxes, airflow distribution and archival rack placement. This study aimed to provide more insight into the relation between the ambient indoor conditions in repositories and the hygrothermal conditions surrounding the collection. Comprehensive measurements were performed in a case study archive to collect ambient, local and near-object conditions. Both measurements and computational fluid dynamics (CFD) modeling were used to research temperature/relative humidity gradients and airflow distribution with a changing rack orientation, climate control strategy and supply as well as exhaust set-up in a repository. The following conclusions are presented: (i) supplying air from one air handling unit to multiple repositories on different floors leads to small temperature differences between them. Differences in ambient and local climates are noticed; (ii) archival boxes mute and delay variations in ambient conditions as expected—however, thermal radiation from the building envelope may have a large influence on the climate conditions in a box; (iii) adopting night reduction for energy conservation results in an increased influence of the external climate, with adequate insulation, this effect should be mitigated; and (iv) the specific locations of the supply air and extraction of air resulted in a vertical gradient of temperature and insufficient mixing of air, and adequate ventilation strategies should enhance sufficient air mixing in combination with the insulation of external walls, and gradient forming should be reduced.

The Role of Porous Media in Homogenization of High Pressure Diesel Fuel Spray Combustion

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel
Keyword(s):  
High Pressure ◽  
Porous Media ◽  
High Speed ◽  
Fuel Spray ◽  
Compression Ignition Engines ◽  
System Pressure ◽  
Novel Approach ◽  
Air Mixing ◽  
The Media

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

The Influence of Singlet Oxygen and Ozone on the Combustion in Methane-Air Mixture

2013 ◽  
Vol 699 ◽  
pp. 111-118
Author(s):  
Rui Shi ◽  
Chang Hui Wang ◽  
Yan Nan Chang
Keyword(s):  
Singlet Oxygen ◽  
Chemical Kinetics ◽  
Mole Fraction ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Combustion Products ◽  
Flame Speed ◽  
Air Mixing

Based on GRI3.0, we study the main chemical kinetics process about reactions of singlet oxygen O2(a1Δg) and ozone O3 with methane-air combustion products, inherit and further develop research in chemical kinetics process with enhancement effects on methane-air mixed combustion by these two molecules. In addition, influence of these two molecules on ignition delay time and flame speed of laminar mixture are considered in our numerical simulation research. This study validates the calculation of this model which cotains these two active molecules by using experimental data of ignition delay time and the speed of laminar flame propagation. In CH4-air mixing laminar combustion under fuel-lean condition(ф=0.5), flame speed will be increased, and singlet oxygen with 10% of mole fraction increases it by 80.34%, while ozone with 10% mole fraction increase it by 127.96%. It mainly because active atoms and groups(O, H, OH, CH3, CH2O, CH3O, etc) will be increased a lot after adding active molecules in the initial stage, and chain reaction be reacted greatly, inducing shortening of reaction time and accelerating of flame speed. Under fuel rich(ф=1.5), accelerating of flame speed will be weakened slightly, singlet oxygen with 10% in molecular oxygen increase it by 48.93%, while ozone with 10% increase it by 70.25%.

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