Curve fits of JANAF thermochemical data

Perini, L.L.

doi:10.2172/4263841

Cited by 18 publications

(8 citation statements)

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“…The thermodynamic state variables calculated by this model are compared with those determined from the JANNAF thermochemical data base [15] in Table 1. The errors produced by the present model are small, and therefore are neglected.…”

Section: Chemistry Chemical Modelmentioning

confidence: 99%

Thermochemical Relaxation in Shock Tunnels

Park

2006

Journal of Thermophysics and Heat Transfer

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Thermochemical relaxation phenomena in the shock tunnel nozzle and behind a normal shock wave formed in its test section are investigated theoretically in one dimension using a state-to-state description. Test gas is assumed to be air containing hydrogen as an impurity. The state-to-state rate coefficients calculated by the forced harmonic oscillator model of Adamovich, Macheret, Rich, and Treanor ("Vibrational Energy Transfer Rates Using a Forced pages 57-65) are multiplied by correction factors to numerically reproduce the existing experimental data on vibrational relaxation times and dissociation rates. The calculations show that freezing in the nozzle causes the relaxation behind a normal shock wave to be generally different from that in free flight. In a shock tunnel with a nozzle length of 5 meters operating at a reflected-shock pressure of 1000 atmosphere, standard, free-flight conditions are simulated fairly closely in its test section. Nomenclature A= nozzle cross-sectional area a i = coefficients in Eq.(1) C = average molecular speed, cm=s c = continuum (free) state E v = energy level of state v, cm 1 , or erg H = enthalpy, erg=g or MJ=kg I = radiation intensity, arbitrary units Kv; v 0 = rate coefficient for v-to-v 0 transition, cm 3 =s k = Boltzmann constant 1:3806 10 16 erg=K M = colliding species m = mass of one atom or molecule, g n = number density, cm 3 p = pressure, dyne=cm 2 or atm T = translational-rotational temperature, K T ve = hypothetical vibrational temperature of a harmonic oscillator having the same vibrational energy as the given vibrational distribution T v1 = vibrational temperature by ratio of v 1 to v 0 state populations u = flow velocity, cm=s u s = shock velocity in a shock tube, cm=s v = vibrational quantum number, or initial state v max = maximum vibrational quantum number v 0 = final state vibrational quantum number X = mol fraction of species X x = distance from throat or shock wave, cm = cross section, cm 2 v = vibrational relaxation time, s Subscripts m = molecule p = peak in radiation 0 = settling chamber * = nozzle throat

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Section: Chemistry Chemical Modelmentioning

confidence: 99%

Thermochemical Relaxation in Shock Tunnels

Park

2006

Journal of Thermophysics and Heat Transfer

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“…The chemical equilibrium calculations are carried out to determine the reflected flow parameters: pressure, temperature, and enthalpy. The calculations are based on the method originally given by Gorden and McBride [18] and use of the JANNAF coefficients [19]. For shock velocities tested in this study, the chemical equilibrium calculations give the reflected flow parameters as listed in Table 5.…”

Section: Resultsmentioning

confidence: 99%

Experimental study of shock tunnel flow with a stationary throat plug

2012

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A throat plug is a device to prevent fragments produced by the bursting of the primary diaphragm of a shock tunnel from entering the nozzle and damaging the model. An experimental study has been carried out to investigate the flow in the KAIST shock tunnel with two stationary throat plugs at primary shock velocities of 1.19 and 1.28 km/s. These shocks generate tailored conditions when helium and air are used as the driver and driven gases, respectively, at room temperature. Nozzle reservoir pressures and Pitot pressures at the nozzle exit are measured to examine the influence of the stationary throat plug on these properties. The throat plug that has an areal blockage of 6.2 % is found to have negligible effects on shock tunnel flow. However, the throat plug of 19.4 % blockage shows an appreciable influence by generating a pressure bump. Although it retards the establishment time of the nozzle flow, after the transient period, it does not cause deviation of the pressure from that for the clean nozzle configuration. It is found that the reduction of the cross-sectional area, which results from the presence of the throat plug, causes the pressure bump. By increasing the diameter of the driven tube in the region where the throat plug is located appropriately, the magnitude of the pressure bump is reduced significantly.

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“…Each species has (next to its molar weight) a set of six coefficients for different temperature ranges: 500 K until 3000 K, 3000 K until 6000 K, and above 6000 K. These coefficients are called JANAF thermodynamic coefficients and they represent the following variables: H 298 f , S c , H c , a 1 , a 2 , and a 3 . [75] These variables represent respectively the heat of formation at 298.13 K, the reference entropy (Eq. (C.1)), the reference enthalpy (Eq.…”

Section: C1 Thermmentioning

confidence: 99%

Nitrogen Catalytic Recombination on Copper Oxide in Tertiary Gas Mixtures

Cheung

Schrijer

Park

2016

Journal of Spacecraft and Rockets

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PrefaceThis master thesis represents the work that I have conducted at KAIST (Republic of Korea) from July 2013 until December 2013 and August 2014 until March 2015. During these period I have studied the field of aerothermodynamics, learned the necessary steps to conduct experiments individually, explored and studied various numerical programs to fulfill the goal of this research. This thesis is the final step in the journey to acquire the degree of Master of Science in Aerospace Engineering at Delft University of Technology.This report consists of three main parts. One part discusses the shock tube and the fabrication of heat transfer gauges. The second part introduces the numerical programs which are used to simulate the conditions inside the shock tube and around the model, whereas the third part covers the theory regarding heat flux and catalycity. These three parts together form a chain of required steps to acquire the desired results for this thesis.

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Curve fits of JANAF thermochemical data

Cited by 18 publications

References 0 publications

Thermochemical Relaxation in Shock Tunnels

Thermochemical Relaxation in Shock Tunnels

Experimental study of shock tunnel flow with a stationary throat plug

Nitrogen Catalytic Recombination on Copper Oxide in Tertiary Gas Mixtures

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