Rotational Temperature measurements by pure rotational O2 CARS in repetitively pulsed low temperature, low pressure non-equilibrium plasma

2013 ◽  
Author(s):  
Suzanne Lanier ◽  
Sherrie Bowman ◽  
Walter Lempert ◽  
Igor Adamovich
Keyword(s):  
Low Temperature ◽  
Rotational Temperature ◽  
Low Pressure ◽  
Temperature Measurements ◽  
Equilibrium Plasma ◽  
Non Equilibrium

scholarly journals Flow reactor studies of non-equilibrium plasma-assisted oxidation of n -alkanes

2015 ◽  
Vol 373 (2048) ◽  
pp. 20140344 ◽  
Author(s):  
Nicholas Tsolas ◽  
Jong Guen Lee ◽  
Richard A. Yetter
Keyword(s):  
Low Temperature ◽  
Fuel Consumption ◽  
Flow Reactor ◽  
Negative Temperature ◽  
Intermediate Species ◽  
Chain Branching ◽  
Temperature Changes ◽  
Equilibrium Plasma ◽  
Elevated Pressures ◽  
Non Equilibrium

The oxidation of n -alkanes (C 1 –C 7 ) has been studied with and without the effects of a nanosecond, non-equilibrium plasma discharge at 1 atm pressure from 420 to 1250 K. Experiments have been performed under nearly isothermal conditions in a flow reactor, where reactive mixtures are diluted in Ar to minimize temperature changes from chemical reactions. Sample extraction performed at the exit of the reactor captures product and intermediate species and stores them in a multi-position valve for subsequent identification and quantification using gas chromatography. By fixing the flow rate in the reactor and varying the temperature, reactivity maps for the oxidation of fuels are achieved. Considering all the fuels studied, fuel consumption under the effects of the plasma is shown to have been enhanced significantly, particularly for the low-temperature regime ( T <800 K). In fact, multiple transitions in the rates of fuel consumption are observed depending on fuel with the emergence of a negative-temperature-coefficient regime. For all fuels, the temperature for the transition into the high-temperature chemistry is lowered as a consequence of the plasma being able to increase the rate of fuel consumption. Using a phenomenological interpretation of the intermediate species formed, it can be shown that the active particles produced from the plasma enhance alkyl radical formation at all temperatures and enable low-temperature chain branching for fuels C 3 and greater. The significance of this result demonstrates that the plasma provides an opportunity for low-temperature chain branching to occur at reduced pressures, which is typically observed at elevated pressures in thermal induced systems.

Spectroscopic studies of low-pressure flames; temperature measurements in acetylene flames

1948 ◽  
Vol 194 (1037) ◽  
pp. 169-184 ◽  
Keyword(s):  
Reaction Zone ◽  
Rotational Temperature ◽  
Flame Temperature ◽  
Low Pressure ◽  
Spectroscopic Studies ◽  
Rotational Energy ◽  
Temperature Measurements ◽  
Oh Radicals ◽  
Electronically Excited ◽  
Combustion Processes

Flames at very low pressure haw a relatively thick reaction zone (or flame front) and are especially suitable for detailed study of the combustion processes and of the distribution of energy during the reaction. Temperature measurements have been made, by various spectroscopic methods, on flames of acetylene with air, oxygen and nitrous oxide, in some cases down to a pressure of 1.5 mm. Hg. The excitation temperature has been measured through the reaction zone by the spectrum-line reversal method using Fe, introduced as the carbonyl; the characteristics of the flame containing Fe(CO) 5 are described. The rotational temperature of the excited OH radicals has been determined from the emission spectrum; at pressures above 10 mm. it is fairly constant at around 5700° K, but at lower pressure rises to a higher value of nearly 9000° K. The results are explaihed in terms of the collision and radiative deactivation of the electronically excited OH radicals. These radicals are believed to be formed, as the result of chemical reaction, in the excited 2 Σ state and with a rotational energy equivalent to above 9000° K. Deactivation by collision appears to occur on the average after about forty collisions, if a normal collision diameter is assumed. Removal of electronic excitation occurs mainly by collisions with O 2 molecules, but CO 2 or CO molecules are most effective in removing rotational energy. The variation of concentration of OH through the reaction zone has been determined by its absorption spectrum; it is abnormally high just below the visible reaction zone. Calculations of flame temperature and composition are given. The lack of equipartition of energy is discussed.

Activation of the low-temperature non-equilibrium plasma water

2015 ◽  
pp. 359-361
Author(s):  
Michail Bruyako ◽  
Larisa Grigorieva ◽  
Angela Orlova ◽  
Vyacheslav Pevgov
Keyword(s):  
Low Temperature ◽  
Equilibrium Plasma ◽  
Non Equilibrium
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