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This burner can produce MILD combustion regime in the upstream and conventional combustion regime in the downstream.
Detailed combustion analysis suggests that preheated jatropha oil gives identical combustion as that of mineral diesel.
The latter is often considered a more hazardous type of smoldering combustion, because it can persist for a long period of time and can transition into flaming combustion.
Partial premixing and combustion cause more substantive changes to the CRZ than pure diffusive combustion.
This suggests that external group combustion is likely to occur and this is also confirmed by the estimation of group combustion number.
This behaviour is similar to the combustion of more complex hydrocarbon fuels.
Journal ArticleDOI
HD Ross, SR Gollahalli 
110 Citations
Microgravity Combustion brings together, for the first time, a large and growing literature on combustion in microgravity, as collated and described by recognized experts in the field of combustion science, who are active in the specialty of combustion science in microgravity.
Smoldering combustion contributes to a higher EF and a more complex composition.
The prospect of using a flamelet-based combustion model is encouraging.
In addition, the combustor exhibited a large region of stable, acoustically clean combustion that is suitable for preliminary validation of LES models.
It supports the hypothesis that flamelet-like combustion is still found above the Klimov–Williams criterion.
Oscillatory combustion may take place if the L* is small enough.
In-combustor stirring clearly plays a large role even in premixed combustion.
It may be thought to offer enhanced combustion stability when compared to the lean premixed combustion systems.
This is probably related to the in-cylinder combustion.
combustion, supports the existence of a warm electric discharge.
Theoretical analyses of flaming combustion will be possible, leading to a better understanding of materials combustion.
These suggest that the combustion process was essentially isochemical on a large scale.
This is supported by analysis of the supersonic combustion regime, showing an expected flamelet-like behaviour.

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Impact of roof geometry of an isolated leeward sawtooth roof building on cross-ventilation: Straight, concave, hybrid or convex?
5 answers
The impact of roof geometry on cross-ventilation in an isolated leeward sawtooth roof building varies based on the roof pitch and eave inclination angle. A steeper roof pitch can lead to higher velocity magnitudes at openings due to pressure differences. Additionally, the presence of eaves affects airflow behavior, with leeward eaves promoting increased ventilation rates and windward eaves causing more blockage of airflow as the roof pitch steepens. Furthermore, the surrounding urban geometry significantly influences turbulent opening velocities and indoor airflow characteristics, emphasizing the importance of neighboring buildings in cross-ventilation. Understanding these factors is crucial for optimizing ventilation rates in naturally ventilated buildings with different roof geometries.
Why do conventional wood burners produce more emissions than improved burners?
5 answers
Conventional wood burners produce more emissions than improved burners due to several factors. Improved burners, such as advanced biomass gasifier cooking stoves, utilize innovative features like negative pressure systems and integrated combustion processes, resulting in higher thermal efficiency and lower pollutant emissions. Additionally, the design modifications in improved burners lead to reduced emissions of CO, TSP, OC, EC, and PAHs compared to traditional stoves. Furthermore, the use of biomass briquettes/pellets in advanced stoves is more efficient and environmentally friendly than burning raw biomass, as it eliminates a significant portion of CO2 and PM2.5 emissions. In summary, the advancements in burner technology, including better combustion processes and fuel types, contribute to the decreased emissions observed in improved burners compared to conventional wood burners.
How to analyze the Global market demand for superheated steam dryers?
4 answers
Analyzing the global market demand for superheated steam dryers involves considering various factors. The use of superheated steam as a drying medium offers advantages such as energy efficiency, environmental friendliness, and safety compared to traditional methods like hot air. However, challenges exist in the widespread adoption of this technology, including high equipment costs and low industrialization levels in certain regions like China. Innovative systems have been developed to address these challenges, such as closed-loop superheated-steam drying systems that enhance energy efficiency and product quality while being environmentally friendly and safe. Understanding these technological advancements and market dynamics is crucial for assessing the global demand for superheated steam dryers and promoting their sustainable integration into various industries.
What are the key performance indicators for a successful striper of post-combustion CO2 using MEA?
5 answers
The key performance indicators for a successful stripper in post-combustion CO2 capture using monoethanolamine (MEA) include the reduction in re-boiler duty, specific re-boiler duty, and total energy consumption. Process modifications such as multi absorber feed with inter-heating stripper have been shown to reduce the re-boiler duty by 11% compared to conventional configurations, leading to lower energy consumption. Additionally, the regeneration energy for MEA-based post-combustion carbon capture using multi absorber feed and inter-heating stripper was found to be 3.78 MJ/kg CO2, indicating efficient performance. Furthermore, studies comparing MEA with diethanolamine (DEA) showed that DEA generally has better thermal performance, providing energy savings of 0.27% to 4.50% in various process configurations. These indicators collectively demonstrate the effectiveness of MEA-based post-combustion CO2 capture systems with optimized strippers.
Download this pdf Design, construction and performance evaluation of a biomass cookstove.
5 answers
The design, construction, and performance evaluation of biomass cookstoves are crucial for enhancing efficiency and reducing emissions. Various studies have focused on optimizing biomass cookstoves by considering factors like natural and forced drafts, heat transfer, fluid flow, insulation, and air supply. Experimental evaluations, such as water boiling tests, time-to-boil methods, and emission tests, have been utilized to measure thermal efficiency, energy uptake, and pollutant emissions. The development of advanced biomass cookstoves incorporating technologies like air preheating, correct air supply, and gasification techniques has shown promising results in improving fuel efficiency and reducing pollutant emissions. These advancements aim to address indoor air pollution issues associated with traditional cookstoves, particularly in developing countries, by providing cleaner and more efficient cooking options.
What is volatile matter in biomass during torrefaction significant?
4 answers
Volatile matter in biomass during torrefaction is significant due to its role in energy recovery and fuel properties enhancement. Torrefaction, a mild pyrolysis process, reduces the hemicellulose content of biomass, leading to the generation of volatile products. These volatiles, which include condensable gases, can be utilized as an auxiliary energy source for feedstock drying and torrefaction processes, contributing to energy recovery and supplementing the energy required for torrefaction. Moreover, torrefaction increases the calorific value of biomass by devolatilizing water and oxygenated compounds, enhancing its energy content on both mass and volumetric bases. The decrease in volatile matter content during torrefaction enriches the lignin content of the biomass, making it a more suitable feedstock for energy production.
What is hydrogen content in biomass during torrefaction significant?
5 answers
During torrefaction, the hydrogen content in biomass undergoes a significant decrease. The process of torrefaction, which involves heating biomass in an inert atmosphere, leads to the removal of volatile compounds like hemicelluloses, resulting in a reduction in hydrogen content. Specifically, as the torrefaction temperature increases, the hydrogen content in the biomass decreases, contributing to an increase in the carbon content of the torrefied biomass. This decrease in hydrogen content is essential for enhancing the energy density of biomass and improving its combustion characteristics, making it a more efficient fuel source. Therefore, monitoring and controlling the hydrogen content during torrefaction is crucial for optimizing the quality and energy efficiency of the resulting torrefied biomass.
What is typical cellulose, xylan, pectin, xyloglucan, starch, and inulin content of poaceae leaves in percentages?
5 answers
The typical composition of various polysaccharides in Poaceae leaves can vary. Cellulose content in primary plant cell walls ranges from 9-25%. Xylan is a component of hemicelluloses, constituting 25-50% of the primary cell wall. Pectin, another primary cell wall component, makes up 10-35% of the cell wall. Xyloglucans, which attach to cellulose microfibrils, are present in varying amounts. Starch content in leaves can be monitored using Raman microscopy, aiding in biomass predictions. In Poaceae, the intragenomic base composition heterogeneity analysis revealed distinct base composition patterns, aiding in taxonomic classification within the family. The specific percentages of starch and inulin in Poaceae leaves were not directly provided in the contexts.
Why choose CA25 in gasoline engine under Nanosecond pulse discharge?
4 answers
CA25 is chosen in gasoline engines under nanosecond pulse discharge due to its ability to form a volumetric multi-channel streamer discharge at a low energy consumption of 60 mJ cycle−1 under high back pressure conditions of 1400 kPa. This discharge method allows for the formation of a spatially dispersed initial flame kernel at a position of high electric field strength around the central electrode, leading to a shortened initial combustion period compared to conventional spark ignition. Additionally, the use of nanosecond duration repetitively pulsed plasma discharge devices has shown a significant reduction in ignition time for air-hydrocarbon mixtures, including gasoline, when compared to traditional spark ignition systems. The development of nanosecond scale discharges in a point-to-plane configuration has also been found to be effective in chemically activating air-hydrocarbon mixtures in automotive engines.
What is the typical efficiency of a hydrogen gas turbine?
9 answers
The typical efficiency of hydrogen gas turbines varies significantly depending on the specific technology and configuration used. For instance, a thermodynamic model integrating combustion chemical kinetics into a gas turbine system showed that the system's performance and emissions are highly influenced by the addition of hydrogen, with isentropic efficiencies of the turbine and compressor playing a crucial role in overall system performance. However, an exact efficiency figure is not provided in this context. In contrast, a redesigned Brayton cycle fueled with humidified ammonia/hydrogen blends achieved efficiencies up to 43.3%, indicating the potential for higher efficiency in systems optimized for hydrogen use. A proposed high-efficiency power cycle using hydrogen as a working fluid in a regenerative closed Brayton cycle suggested that about 90 percent of the high-temperature heat input could be converted to electricity, although this is more indicative of the cycle's thermal efficiency rather than the gas turbine's electrical efficiency. Meanwhile, a combined cycle power plant (CCPP) analysis showed that hydrogen-rich fuel could lead to varying CO2 emission reductions and efficiency changes, depending on the hydrogen content and production method, but again, specific efficiency figures for the gas turbine component were not detailed. Life cycle analysis of greenhouse gas and NOx emissions from power regenerated through hydrogen-fueled gas turbines highlighted the importance of renewable power sources, net CCGT efficiency, and hydrogen production efficiency on the environmental impact, but specific efficiency metrics were not directly addressed. Micro gas turbines (MGTs) redeveloped for methane/hydrogen blended fuel demonstrated the capability for stable operation with minimal greenhouse gas production, yet efficiency figures were not explicitly mentioned. Research into gas turbine power systems operating on pure hydrogen or hydrogen-natural gas mixtures emphasized the challenges and potential efficiency improvements but did not provide a generalized efficiency figure. A novel solid oxide fuel cell (SOFC)/gas turbine (GT) hybrid cycle system with CO2 capture was analyzed, showing an efficiency of around 64.13%, which is significantly higher than traditional systems but is specific to this hybrid configuration. Combustion characterization in a non-premixed gas turbine burner indicated that hydrogen blending could increase peak temperatures and potentially affect efficiency, though specific efficiency outcomes were not quantified. Lastly, a novel plant design based on reversible solid oxide cells and integrated with various energy systems showed a hydrogen production efficiency of about 39%, with the total plant efficiency reaching about 47% when accounting for heat, cool, and freshwater production. In summary, while specific efficiency figures for hydrogen gas turbines are not uniformly detailed across these contexts, the data suggests that efficiencies can range significantly based on the system design, hydrogen blending levels, and integration with other technologies, with some configurations achieving efficiencies above 60%.
Do conventional wood stoves ahve the lowest efficiency?
5 answers
Conventional wood stoves generally exhibit lower efficiency compared to improved designs. Research findings indicate that traditional wood-burning stoves have notably low thermal efficiency, ranging from 2.6% to 5.21%. In contrast, studies on enhanced stove designs show significant improvements in efficiency. For instance, a study on improved stoves with optimized features like cylinder shape, specific air supplies, and insulation materials demonstrated much higher thermal efficiency, reaching up to 35.5%. These findings highlight the substantial efficiency gains achievable through the adoption of enhanced stove technologies, emphasizing the importance of transitioning from conventional to improved stove models for increased energy efficiency and reduced environmental impact.