Experimental Study in H2/CO/CH4–Air and H2/CO/C3H8–Air Premixed Flames. Part 2: Cellular Instabilities

2011 ◽  
Vol 673 ◽  
pp. 71-76
Author(s):  
Tran Manh Vu ◽  
Jeong Park ◽  
Jeong Soo Kim ◽  
Oh Boong Kwon ◽  
Jin Han Yun ◽  
...  
Keyword(s):  
Experimental Study ◽  
Carbon Monoxide ◽  
Combustion Chamber ◽  
Room Temperature ◽  
Constant Pressure ◽  
Premixed Flames ◽  
Elevated Pressures ◽  
Schlieren System ◽  
Flame Instabilities

Experiments in a constant pressure combustion chamber at room temperature and elevated pressures using schlieren system were conducted to investigate the cellular instabilities in hydrogen/carbon monoxide/methane (or propane)–air premixed flames. In the present study, hydrodynamic and diffusional-thermal instabilities were evaluated to elucidate their effects to flame instabilities. Effective Lewis numbers of premixed flames with methane addition decrease for all of the cases. Meanwhile, the effective Lewis numbers with propane addition increase for lean and stoichiometric conditions, but they increase for rich and stoichiometric cases for hydrogen-enriched flames. With propane addition, the propensity for cells formation is significantly diminished whereas the cellular instabilities for hydrogen enriched flames are promoted. With methane addition, the similar behavior of cellularity is obtained, indicating that methane is not a candidate for suppressing cells formation in hydrogen/carbon monoxide/methane–air premixed flames.

Experimental Study in H2/CO/CH4-Air and H2/CO/C3H8-Air Premixed Flames. Part 1: Laminar Burning Velocities and Markstein Lengths

2011 ◽  
Vol 673 ◽  
pp. 65-70
Author(s):  
Tran Manh Vu ◽  
Jeong Park ◽  
Jeong Soo Kim ◽  
Oh Boong Kwon ◽  
Jin Han Yun ◽  
...  
Keyword(s):  
Experimental Study ◽  
Carbon Monoxide ◽  
High Speed ◽  
Room Temperature ◽  
Constant Pressure ◽  
Propagation Characteristics ◽  
Elevated Pressures ◽  
Numerical Predictions ◽  
Schlieren System ◽  
Good Agreement

Flame propagation characteristics of hydrogen/carbon monoxide/methane (or propane)–air premixed mixtures were studied in a constant pressure combustion chamber with a schlieren system at room temperature and elevated pressures. Unstretched laminar burning velocities and Markstein lengths of various mixtures were obtained by analyzing high-speed schlieren images. Also, the experimentally measured unstretched laminar burning velocities were compared with numerical predictions using the PREMIX code with a H2/CO/C1–C4 mechanism, USC Mech II, developed by Wang et al. [23]. The two data from experiments and predictions show good agreement. The results indicate a significant increase in the unstretched laminar burning velocities with hydrogen enrichment and a decrease with the addition of hydrocarbons, whereas the opposite effects for the Markstein lengths were observed.

Experimental study on cellular instabilities in hydrocarbon/hydrogen/carbon monoxide–air premixed flames

2011 ◽  
Vol 36 (11) ◽  
pp. 6914-6924 ◽  
Author(s):  
Tran Manh Vu ◽  
Jeong Park ◽  
Jeong Soo Kim ◽  
Oh Boong Kwon ◽  
Jin Han Yun ◽  
...  
Keyword(s):  
Experimental Study ◽  
Carbon Monoxide ◽  
Premixed Flames

scholarly journals Composite Material of PDMS with Interchangeable Transmittance: Study of Optical, Mechanical Properties and Wettability

2021 ◽  
Vol 5 (4) ◽  
pp. 110
Author(s):  
Flaminio Sales ◽  
Andrews Souza ◽  
Ronaldo Ariati ◽  
Verônica Noronha ◽  
Elder Giovanetti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Room Temperature ◽  
Casting Process ◽  
Optical Characteristics ◽  
Smart Devices ◽  
Superhydrophobic Coating ◽  
Gravity Casting ◽  
High Flexibility ◽  
Physical And Chemical

Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 °C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures.

Carbon monoxide formation as an intermediate product in photocatalytic steam reforming of methane with lanthanum-doped sodium tantalate

2021 ◽  
Author(s):  
Wirya Sarwana ◽  
Akihiko Anzai ◽  
Daichi Takami ◽  
Akira Yamamoto ◽  
Hisao Yoshida
Keyword(s):  
Carbon Monoxide ◽  
Solar Energy ◽  
Steam Reforming ◽  
Intermediate Product ◽  
Room Temperature ◽  
Carbon Monoxide Formation ◽  
Steam Reforming Of Methane

Photocatalytic steam reforming of methane (PSRM) has been studied as an attractive method to produce hydrogen by utilizing photoenergy like solar energy around room temperature with metal-loaded photocatalysts, where methane...

scholarly journals Room-temperature carbon monoxide oxidation by oxygen over Pt/Al2O3 mediated by reactive platinum carbonates

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Mark A. Newton ◽  
Davide Ferri ◽  
Grigory Smolentsev ◽  
Valentina Marchionni ◽  
Maarten Nachtegaal
Keyword(s):  
Carbon Monoxide ◽  
Room Temperature ◽  
Carbon Monoxide Oxidation

Piezoresistivity and Electrical Resistance Relaxation of Polyisoprene Nanostructured Carbon Allotrope Hybrid Composites

2015 ◽  
Vol 1117 ◽  
pp. 52-55
Author(s):  
Artis Linarts ◽  
Maris Knite
Keyword(s):  
Electrical Resistance ◽  
Room Temperature ◽  
Constant Pressure ◽  
Hybrid Composites ◽  
Conductive Filler ◽  
Force Sensor ◽  
Filler Concentration ◽  
Nanostructured Carbon ◽  
Carbon Allotrope ◽  
Resistance Relaxation

Polymer conductive filler composites are believed to be promising materials for flexible force sensor manufacture. Polyisoprene various carbon allotrope hybrid composites were made and their piezoresistive properties depending on the two type’s filler concentration and their ratio have been determined. Electrical resistance relaxations of hybrid composites at constant pressure in room temperature were determined as well. Experimental data of resistance relaxation was analyzed and fitted similarly to stress relaxation of polymers at constant pressure.

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