scholarly journals Swirler geometry effects (dh/do ratio) on synthetic gas flames: Part 1: Combustion and emission characteristics

Energetika ◽  
2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Harun Yilmaz ◽  
Omer Cam ◽  
Ilker Yilmaz
Keyword(s):  
Room Temperature ◽  
Swirling Flow ◽  
Pollutant Emissions ◽  
Emission Characteristics ◽  
Atmospheric Conditions ◽  
Data Logger ◽  
Swirl Number ◽  
Synthetic Gas ◽  
Performance Results ◽  
The City

Swirling flows increase combustion performance via favouring flame stability, pollutant emissions, and combustion intensity. The strength of a swirling flow is characterized by a parameter known as swirl number, which is highly related to the dh/do ratio. In this study, effects of the swirler dh/do ratio on combustion and emission characteristics of the synthetic gas flames of premixed 20%CNG/30%H2/30%CO/20%CO2 mixture were experimentally investigated in a laboratory-scale swirl stabilized combustor. For this purpose, twelve different swirl generators were designed and manufactured. dh/do ratios of these swirlers were set as 0.30 and 0.50, and the geometric swirl number was varied between the values of 0.4 and 1.4 (at 0.2 intervals). All experiments were conducted at a fuel-lean equivalence ratio (ϕ = 0.6), room temperature, and local atmospheric conditions of the city of Kayseri, Turkey. A data logger was utilized to plot axial and radial temperatures and NOx, CO, and CO2 profiles, which were exploited to assess combustion and emission performance. Results showed that the dh/do ratio had a non-monotonic effect on the behaviour of combustion and emission of the tested synthetic gas mixture. Depending on the swirl number, increments and decrements were observed in temperature and emission values.

scholarly journals An experimental study on premixed CNG/H2/CO2 mixture flames

2018 ◽  
Vol 8 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Ilker Yilmaz ◽  
Harun Yilmaz ◽  
Omer Cam
Keyword(s):  
Experimental Study ◽  
Thermal Power ◽  
The Other ◽  
Gas Composition ◽  
Atmospheric Conditions ◽  
Swirl Number ◽  
Combustion Performance ◽  
Temperature Distributions ◽  
The City ◽  
Flame Behaviour

Abstract In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.

Effects of Swirler Configurations on Flow Structures and Combustion Characteristics

2004 ◽  
Author(s):  
Guoqiang Li ◽  
Ephraim J. Gutmark
Keyword(s):  
Fuel Injection ◽  
Vortex Breakdown ◽  
Swirling Flow ◽  
Combustion Characteristics ◽  
Pollutant Emissions ◽  
Flow Structures ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Atmospheric Conditions ◽  
Fuel Injector

Modern gas turbine combustion technologies are driven by stringent regulations on pollutant emissions such as CO and NOx. A combustion system of multiple swirlers coupled with distributed fuel injection was studied as a new concept for reducing NOx emissions by application of Lean Direct Injection (LDI) combustion. The present paper investigates the effects of swirler configurations on the flow structures in isothermal flow and combustion cases using a multiple-swirlers fuel injector at atmospheric conditions. The swirling flow field within the combustor was characterized by a central recirculation zone formed after vortex breakdown. The differences between the tangential and axial velocity profiles, the shape of the recirculation zones and the turbulence intensity distribution for the different fuel injector configurations impacted the flame structure, the temperature distribution and the emission characteristics both for gaseous and liquid fuels. Co-swirling configuration was shown to have the lowest NOx emission level compared with the counter-swirling ones for both types of fuels with lower inlet temperature. In contrast to this, the swirl configuration had less effect on the combustion characteristics in the case of gaseous fuel with high air inlet temperature. The differences in NOx emissions were shown to be closely related to the Damkohler number or the degree to which the flame resembled well-mixed combustion, which is the foundation for LDI combustion.

Metabolic response to temperature stress in the Colombian freshwater crab Neostrengeria macropa (H. Milne Edwards, 1853) (Decapoda: Brachyura: Pseudothelphusidae)

2021 ◽  
Author(s):  
David M Hudson
Keyword(s):  
Metabolic Response ◽  
Infrastructure Development ◽  
Predator Prey ◽  
Temperature Range ◽  
Indicator Group ◽  
Response To Temperature ◽  
Performance Results ◽  
The City ◽  
The Ideal

Abstract Freshwater crustaceans are distributed throughout the montane and lowland areas of Colombia, and are therefore a useful indicator group for how aquatic species will respond to climate change. As such, metabolic determination of physiological performance was evaluated for the Colombian pseudothelphusid crab, Neostrengeria macropa (H. Milne Edwards, 1853), over a temperature range inclusive of current temperatures and those predicted by future scenarios in the plateau around the city of Bogotá, namely from 8 °C to 30 °C. The performance results mostly aligned with previous exploratory behavioral determination of the ideal temperature range in the same species, although the metabolism increased at the highest temperature treatments, a point when exploratory behavior declined. These results indicate that this species of montane crab behaviorally compensates for increased thermal stress by decreasing its physical activity, which could have negative predator-prey consequences with changes to community structure as different species undergo climate-mediated geographic range shifts in the region. As this species is endemic to the plateau surrounding Bogotá, it also experiences a number of other stressors to its survival, including infrastructure development and invasive species.

scholarly journals The Atmosphere of the Underground Electric Railways of London: A Study of its Bacterial Content in 1920

1923 ◽  
Vol 22 (2) ◽  
pp. 123-155 ◽  
Author(s):  
J. Graham Forbes
Keyword(s):  
Body Temperature ◽  
Room Temperature ◽  
The Mean ◽  
Bacterial Content ◽  
The City

1. The bacterial content of the air of the Underground Railways, when the average of all results of the bacteriological investigations is taken, does not numerically compare unfavourably with the outside air of London.2. The ratio of the number of organisms growing at room temperature appears to be about 14 for railway air to 10 outside air. For those growing at body temperature the ratio is considerably higher, namely 2 to 1 respectively. The mean per litre, for room temperature organisms, is about 9 in railway air, 6·3 in the outside air; for body temperature organisms 4·6 for railway air, 2·2 for outside air.3. The bacterial content of platform air, except on the City and South London Railway, would appear to be higher than that of carriage air; the total mean for platform air being 52 and for carriage air 42·8 organisms per 5 litres, or a ratio of 16·4 and 13·5 respectively to 10 of the open air. The higher proportion in platform air is generally speaking to be accounted for by the greater amount of draught and dust disturbance.4. The ratios of the total bacterial content of railway carriage air and carriage and platform air on the six lines to open air are estimated in the following proportions:

Development of Rotary Engine Based Micro-DG/CHP System

2016 ◽  
Author(s):  
Richard L. Hack ◽  
Max R. Venaas ◽  
Vince G. McDonell ◽  
Tod M. Kaneko
Keyword(s):  
Distributed Generation ◽  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Rotary Engine ◽  
Chp System ◽  
Performance Results

Small scale Distributed Generation with waste heat recovery (<50 kW power output, micro-DG/CHP) is an expanding market supporting the widespread deployment of on-site generation to much larger numbers of facilities. The benefits of increased overall thermal efficiency, reduced pollutant emissions, and grid/microgrid support provided by DG/CHP can be maximized with greater quantities of smaller systems that better match the electric and thermal on-site loads. The 3-year CEC funded program to develop a natural gas fueled automotive based rotary engine for micro-DG/CHP, capitalizing upon the unique attributes engine configuration will be presented including initial performance results and plans for the balance of the program.

Topological Flow Structures of Annular Swirling Jets

2001 ◽  
Vol 17 (3) ◽  
pp. 131-138
Author(s):  
Feng Chin Tsai ◽  
Rong Fung Huang
Keyword(s):  
Vortex Breakdown ◽  
Swirling Flow ◽  
Single Bubble ◽  
Flow Structures ◽  
Complex Flow ◽  
Swirl Number ◽  
Recirculation Bubble ◽  
Annular Jet ◽  
Ring Mode ◽  
Dual Ring

AbstractThe effects of blockage and swirl on the macro flow structures of the annular jet past a circular disc are experimentally studied through the time-averaged streamline patterns. In the blockage-effect regime, the flows present multiple modes, single bubble, dual rings, vortex breakdown, and triple rings, in different regimes of blockage ratio and swirl number. The topological models of the flow structures are proposed and discussed according to the measured flow fields to manifest the complex flow structures. The single bubble is a closed recirculation bubble with a stagnation point on the central axis. The dual-ring flow is an open-top recirculsation zone, in which a pair of counter-rotating vortex rings exists in the near wake. The fluids in the dual rings are expelled downstream through a central jet-like swirling flow. A vortex breakdown may occur in the central jet-like swirling flow if the exit swirl number exceeds critical values. When the vortex breakdown interacts with the dual rings, a complex triple-ring flow structure forms. Axial distributions of the local swirl number are presented and discussed. The local swirl number increases with the increase of the exit swirl number and attains the maximum in the dual-ring mode. At large exit swirl numbers where the vortex breakdown occurs, the local swirl number decreases drastically to a low value.

Incessant and economical technique for in-situ preparation of metallicnano on/in polyester fabric

2021 ◽  
Vol 64 (2) ◽  
pp. 68-70
Author(s):  
Satyajeet B. Chaudhari ◽  
Bharat H. Patel ◽  
Aadhar A. Mandot
Keyword(s):  
Metal Ion ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Polyester Fabric ◽  
Atmospheric Conditions ◽  
Spherical Nanoparticles ◽  
In Situ Preparation

Composite textiles consisting of metallic nanoparticles dispersed in textiles fabric have been prepared by the reduction of metal ion from its salt at room temperature under normal atmospheric conditions. Morphology and structures have been investigated by SEM. Spherical nanoparticles were found to be homogeneously dispersed in/on the polyester (PET) fiber and the particles were elementally analyzed by the XRF technique.

scholarly journals Visuospatial Reasoning and Its Relation to External Variables

2014 ◽  
Vol 24 (58) ◽  
pp. 197-204
Author(s):  
Juliana Carnevalli Siqueira Nery ◽  
Fabián Javier Marín Rueda
Keyword(s):  
Age Group ◽  
Older Students ◽  
Normative Sample ◽  
Male And Female ◽  
Visuospatial Reasoning ◽  
External Variables ◽  
Belo Horizonte ◽  
Performance Results ◽  
The City ◽  
Age And Sex

In this study, the relation of age and sex with visuospatial reasoning assessed by the Cube Test was investigated. In addition, a comparative study was conducted between this study sample and the normative group of the test with regard to visuospatial reasoning performance results. Six hundred and eighty-four students participated in this study, from the city of Belo Horizonte (State of Minas Gerais, Brazil), aged between 15 and 57 years old, both male and female. The results showed both age and sex differences, where younger students showed a significantly higher performance than older students and men showed significantly higher averages than women in every test comparison. In the study with the normative sample, men showed higher averages than women throughout every age group and in the overall result of both studies. The results obtained reflect those found in the literature and highlight the influence of age and sex on visuospatial reasoning.

scholarly journals Exploring the Potential of Web Based Information of Business Popularity for Supporting Sustainable Traffic Management

2020 ◽  
Vol 21 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Jorge M. Bandeira ◽  
Pavlos Tafidis ◽  
Eloísa Macedo ◽  
João Teixeira ◽  
Behnam Bahmankhah ◽  
...  
Keyword(s):  
Traffic Management ◽  
Satellite System ◽  
Pollutant Emissions ◽  
Specific Power ◽  
Linear Regression Models ◽  
Data Logger ◽  
Alternative Source ◽  
Traffic Volumes ◽  
Noise Assessment ◽  
Global Navigation Satellite

AbstractThis paper explores the potential of using crowdsourcing tools, namely Google “Popular times” (GPT) as an alternative source of information to predict traffic-related impacts. Using linear regression models, we examined the relationships between GPT and traffic volumes, travel times, pollutant emissions and noise of different areas in different periods. Different data sets were collected: i) crowdsourcing information from Google Maps; ii) traffic dynamics with the use of a probe car equipped with a Global Navigation Satellite System data logger; and iii) traffic volumes. The emissions estimation was based on the Vehicle Specific Power methodology, while noise estimations were conducted with the use of “The Common Noise Assessment Methods in Europe” (CNOSSOS-EU) model. This study shows encouraging results, as it was possible to establish clear relationships between GPT and traffic and environmental performance.

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