scholarly journals Trap, ignition, and diffusion combustion characteristics of active carbon micro-particles at a meso-scale studied by optical tweezers

2014 ◽  
Vol 63 (17) ◽  
pp. 178802
Author(s):  
Huang Xue-Feng ◽  
Li Sheng-Ji ◽  
Zhou Dong-Hui ◽  
Zhao Guan-Jun ◽  
Wang Guan-Qing ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Active Carbon ◽  
Combustion Characteristics ◽  
Diffusion Combustion ◽  
Micro Particles ◽  
And Diffusion ◽  
Meso Scale

scholarly journals Experimental and numerical studies on combustion characteristics of N 2 -diluted CH 4 and O 2 diffusion combustion in a packed bed

2019 ◽  
Vol 6 (9) ◽  
pp. 190492 ◽  
Author(s):  
Houping Li ◽  
Junrui Shi ◽  
Mingming Mao ◽  
Yongqi Liu
Keyword(s):  
Diffusion Processes ◽  
Packed Bed ◽  
Gas Diffusion ◽  
Combustion Characteristics ◽  
Pollutant Emission ◽  
Diffusion Combustion ◽  
No Emission ◽  
Numerical Studies ◽  
And Diffusion ◽  
Co Emission

Experimental and numerical studies were conducted to determine the combustion characteristics of gas diffusion combustion in a porous combustor packed with 2.5 mm or 3.5 mm alumina pellets, special attention being focused on the effect of packed bed height ( h ) on combustion, NO and CO emissions. The pollutant emission of diffusion filtration combustion is studied with different packed bed lengths in the range of 40 mm ≤ h ≤ 240 mm, fixed excess air ratio of 1.88 and fixed gas inlet velocity of 0.06 m s −1 . Results show that both immersed and surface flames coexist in the combustor. Although porous media enhance the mixing and diffusion processes, the diffusion flame shape is still observed from the side and top views of the combustor, and the diffusion filtration retains properties of diffusion combustion. The immersed flame is always observed with increase in h , whereas the height of surface flame decreases. The NO emission decreases sharply when h is increased from 40 mm to 120 mm. However, the NO emission decreases slightly when h > 120 mm. In the investigated range of h , it is shown that h has a significant influence on the CO emission, an increase in h leading to a constant increase in CO for the combustors packed with 2.5 mm or 3.5 mm pellets. The maximum CO emission is 662 ppm and the minimum value is 67 ppm. In the scope of this study, the temperature on the external wall of the combustor reaches 434–513°C.

The Study on PCCI Mode of Diesel Engine Fueled with Methanol/Dimethyl Ether

2014 ◽  
Vol 607 ◽  
pp. 629-632
Author(s):  
Yan Yan ◽  
Yu Sheng Zhang
Keyword(s):  
Dimethyl Ether ◽  
Alternative Fuels ◽  
Volume Fraction ◽  
Good Alternative ◽  
Diffusion Combustion ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
High Temperature Reaction ◽  
Three Stages ◽  
And Diffusion

Taking into account China's abundant coal resources, methanol and DME(Dimethyl Ether) obtained from coal are good alternative fuels. The research project is to utilize the fuel of DME and methanol in diesel engines for new combustion models PCCI (Premixed Charge Compression Ignition).The tests of the PCCI mode with different boundary conditions were studied on PCCI test bench. PCCI combustion is consisted of three stages: low temperature reaction of DME, high-temperature reaction of DME and diffusion combustion reaction of methanol. DME as combustion improver should be kept relatively low concentration, and with the decrease of methanol, its concentration need to be reduced. Methanol and formaldehyde are important parts of HC emission, their volume fraction was about 70%.

Diffusion Combustion Characteristics of H2/Air in the Micro Porous Media Combustor

2012 ◽  
Vol 455-456 ◽  
pp. 413-418
Author(s):  
H.L. Cao ◽  
J.N. Zhao ◽  
K. Zhang ◽  
D.B. Wang ◽  
X.L. Wei
Keyword(s):  
Porous Media ◽  
Combustion Characteristics ◽  
Diffusion Combustion

Regimes of Unstable Expansion and Diffusion Combustion of a Hydrocarbon Fuel Jet

2018 ◽  
Vol 54 (3) ◽  
pp. 255-263 ◽  
Author(s):  
V. V. Lemanov ◽  
V. V. Lukashov ◽  
R. Kh. Abdrakhmanov ◽  
V. A. Arbuzov ◽  
Yu. N. Dubnishchev ◽  
...  
Keyword(s):  
Hydrocarbon Fuel ◽  
Diffusion Combustion ◽  
Fuel Jet ◽  
And Diffusion

scholarly journals Numerical Investigations of Micro-Scale Diffusion Combustion: A Brief Review

2019 ◽  
Vol 9 (16) ◽  
pp. 3356 ◽  
Author(s):  
P. R. Resende ◽  
Mohsen Ayoobi ◽  
Alexandre M. Afonso
Keyword(s):  
Alternative Fuels ◽  
Numerical Models ◽  
Scientific Progress ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Diffusion Combustion ◽  
Great Opportunity ◽  
Numerical Investigations ◽  
Numerical Approaches

With the increasing global concerns about the impacts of byproducts from the combustion of fossil fuels, researchers have made significant progress in seeking alternative fuels that have cleaner combustion characteristics. Such fuels are most suitable for addressing the increasing demands on combustion-based micro power generation systems due to their prominently higher energy density as compared to other energy resources such as batteries. This cultivates a great opportunity to develop portable power devices, which can be utilized in unmanned aerial vehicles (UAVs), micro satellite thrusters or micro chemical reactors and sensors. However, combustion at small scales—whether premixed or non-premixed (diffusion)—has its own challenges as the interplay of various physical phenomena needs to be understood comprehensively. This paper reviews the scientific progress that researchers have made over the past couple of decades for the numerical investigations of diffusion flames at micro scales. Specifically, the objective of this review is to provide insights on different numerical approaches in analyzing diffusion combustion at micro scales, where the importance of operating conditions, critical parameters and the conjugate heat transfer/heat re-circulation have been extensively analyzed. Comparing simulation results with experimental data, numerical approaches have been shown to perform differently in different conditions and careful consideration should be given to the selection of the numerical models depending on the specifics of the cases that are being modeled. Varying different parameters such as fuel type and mixture, inlet velocity, wall conductivity, and so forth, researchers have shown that at micro scales, diffusion combustion characteristics and flame dynamics are critically sensitive to the operating conditions, that is, it is possible to alter the flammability limits, control the flame stability/instability or change other flame characteristics such as flame shape and height, flame temperature, and so forth.

Methyl Oleate Evaluation as a Model Fuel for Peanuts FAME, in an Indirect Injection Diesel Engine

2012 ◽  
Author(s):  
Valentin Soloiu ◽  
Jabeous Weaver ◽  
Marvin Duggan ◽  
Henry Ochieng ◽  
Brian Vlcek ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Methyl Oleate ◽  
Mechanical Efficiency ◽  
Combustion Characteristics ◽  
Heat Fluxes ◽  
Diffusion Combustion ◽  
Combustion Modeling ◽  
Ultra Low Sulfur Diesel ◽  
Auxiliary Power ◽  
Model Fuel

This study investigates the combustion characteristics of methyl oleate (oleic FAME) produced from oleic acid. This compound is the main fatty acid component of peanut FAME, a potential renewable biofuel. Methyl oleate has been suggested in our previous work as a reference fuel or surrogate for biodiesel for advanced research (simulation and experiments), or as an enrichment compound to improve biodiesel’s fuel properties. This investigation compares the combustion and emissions characteristics of methyl oleate to peanut FAME and ultra-low sulfur diesel No. 2 (ULSD), in a single-cylinder indirect injection diesel engine intended for use as an auxiliary power unit. The dynamic viscosity of peanut FAME (P100) and Methyl Oleate (O100) was found to be 5.2 cP and 4.3 cP, respectively, at 40°C. It was determined from the ASTM standards for biodiesel that up to 50% FAME could be run in the engine. The lower heating value of P100 and O100 was 36 MJ/kg and 37 MJ/kg respectively, compared to 42.7MJ/kg for ULSD. With a combustion time of 2ms, P50 and O50 have shown similar combustion characteristics with ignition delays of about 1 ms at 2200rpm, 6.2 imep (100% load). The P50, O50, and ULSD heat release, with premixed phase combining with diffusion combustion, produced maximum values of 20.3 J/CAD, 22.7 J/CAD, and 21.9 J/CAD respectively. The heat fluxes were calculated by the Annand model, and a 2% increase in maximum total heat flux was observed for O50 compared with a maximum value of 1.95 MW/m2 for ULSD and P50. The mechanical efficiency of 77% was similar for all tested FAME blends and ULSD. The NOx increased for P20 by 6% compared with ULSD while for P50 it was similar to the ULSD values. The NOx emissions of methyl oleate showed a similar trend with that of ULSD. The soot values were relatively constant for all of the methyl oleate blends and increased by 14% for P50 when comparing both fuels to ULSD. The findings support the use of methyl oleate as a reference or model fuel for combustion modeling, and as a compound for enriching biodiesel.

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