Temperature measurement in a chemical shock tube by sodium-line reversal and c sub 2 reversal methods

Napier, D.H.; Nettleton, M.A.; Simonson, J. R.; Thackeray, D. P. C.

doi:10.2514/3.2501

Cited by 5 publications

(1 citation statement)

References 2 publications

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“…For example, line reversal techniques have been employed to measure very high temperatures [28][29][30][31]. More recently, a rapid-tuning ring-dye laser was used to measure the temperature behind incident [32] and reflected [33] shock waves by taking the ratio of the 1^(7) and R.^11) OH lines of the A<-X transition near 306.5 nm; the OH was generated in an argon bath seeded with a stoichiometric H 2 -0 2 mixture.…”

Section: Introductionmentioning

confidence: 99%

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Mathieu¹,

Hanson²

1999

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044REPORT Public reporting burden for this collection ot information is estimated to average 1 hour per response, including the time for review ng instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comment regarding this burden estimates or any aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and Shock tubes often experience temperature and pressure nonuniformities behind the reflected shock wave that cannot be neglected in chemical kinetics experiments. Because of increased viscous effects, smaller tube diameters, and nonideal shock formation, the reflected-shock nonidealities tend to be greater in higher-pressure shock tubes. Since the increase in test temperature (AT 5 ) is the most significant parameter for chemical kinetics, experiments were performed in the Stanford High Pressure Shock Tube using infrared emission from a known amount of CO in Argon. From the measured change in vibrationally equilibrated CO emission with time, the corresponding dT 5 /dt (or AT5 for a known time interval) of the mixture was inferred assuming an isentropic relationship between post-shock temperature and pressure changes. For a range of representative conditions in Argon (20-530 Atm, 1240-1900, the test temperature 2 cm from the endwall increased 3-8 K after 100 )J,s and 15-40 K after 500 u,s, depending on the initial conditions. Separate pressure measurements using a shielded piezoelectric transducer confirmed the isentropic assumption. An analytical model of the reflected-shock gas dynamics was also developed. The measured incident-shock axial velocity profile and a model of the boundary layer growth provide the upstream boundary conditions needed to define the properties behind the moving reflected shock. The calculated AT 5 's agree well with those obtained from experiment. The analytical model was used to estimate the effects of temperature and pressure nonuniformities on typical chemical kinetics measurements. When the kinetics are fast and occur in less than 300 |is, the temperature increase is typically negligible, although some correction is suggested for kinetics experiments lasting longer than 500 (xs. The temperature increase, however, has a negligible impact on the measured absorption profiles of OH and CH 3 when using laser absorption diagnostics at 306 and 216 nm, respectively, validating the use of a constant absorption coefficient. Infrared emission experiments are more sensitive to temperature and pressure changes, so T 5 nonuniformities should be taken into account when interpreting IR-emission data. NONIDEAL EFFECTS BEHIND REFLECTED SHOCK WAVES IN A HIGH-PRESSURE SHOCK TUBEEric L. Petersen f and Ronald K. Hanson AbstractShock tubes often experience temperature and pressure nonuniformities behind the reflecte...

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Section: Introductionmentioning

confidence: 99%

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Mathieu¹,

Hanson²

1999

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Effect of ethane addition on propane pyrolysis

Wami

1988

Chem Eng & Technol

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Pyrolysis of propane/argon mixture in the presence of trace quantities (0.1% and 0.9%) of ethane was investigated at reflected shock wave temperatures between 1200 and 2000K. Traces of ethane accelerated propane decomposition at high temperature. However, increase in the quantity of ethane added to propane/argon mixture did not result in the same increase of its accelerating influence. Ethylene, methane and acetylene were the main hydrocarbon reaction products, with small quantities of propylene and ethane detected only at lower temperatures. Below 1500K, addition of ethane slightly enhanced the yields of ethylene and methane at the expense of propylene and ethane respectively. The selectivity for acetylene increased with increasing temperature and with the decline of those for the other products. For none of the products, did the presence of ethane alter the relationship between product formation rates and temperature. The influence of ethane addition on propane pyrolysis at high temperatures was explained in terms of increased radical concentrations, especially hydrogen atoms and vinyl radicals, formed at high conversions. These accounted for the rapid acceleration of propane decomposition and the high yield of acetylene at high temperatures.

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Temperature measurement in a chemical shock tube using chromium hexacarbonyl

Kimber¹,

Napier²

1965

Combustion and Flame

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Temperature measurement in a chemical shock tube by sodium-line reversal and c sub 2 reversal methods

Cited by 5 publications

References 2 publications

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube

Effect of ethane addition on propane pyrolysis

Temperature measurement in a chemical shock tube using chromium hexacarbonyl

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