CaltechAUTHORS: Article
https://feeds.library.caltech.edu/people/Penner-S-S/article.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenFri, 08 Nov 2024 19:17:52 -0800Thermodynamics and chemical kinetics of one-dimensional nonviscous flow through a Laval nozzle
https://resolver.caltech.edu/CaltechAUTHORS:JPC005
Year: 1951
DOI: 10.1063/1.1748400
Explicit relations have been obtained for the enthalpy changes in one-dimensional nonviscous flow through a Laval nozzle, where arbitrary deviations from thermodynamic equilibrium of chemical composition and of internal electronic, vibrational, or rotational energy states may occur. These relations are of interest in connection with calculations on the effect of deviations from equilibrium on performance of jet engines.Starting with the equation of continuity for a multicomponent mixture of reacting gases, criteria for near-equilibrium and for near-frozen flow with respect to chemical reactions are derived. The near-equilibrium criteria agree with results obtained previously. The near-frozen flow criteria are new and have not yet been applied to the study of chemical reactions during nozzle flow.https://resolver.caltech.edu/CaltechAUTHORS:JPC005Quantitative evaluation of rocket propellants
https://resolver.caltech.edu/CaltechAUTHORS:20090805-150338262
Year: 1952
A method for the quantitative evaluation of chemicals as rocket propellants is described. The procedure utilizes the fact that adiabatic expansion through a nozzle may be considered to be isentropic. Treatments are presented for two limiting conditions of expansion, corresponding to flow without chemical change and to flow which is characterized, at all times, by the existence of thermodynamic equilibrium.https://resolver.caltech.edu/CaltechAUTHORS:20090805-150338262Chemical propellants
https://resolver.caltech.edu/CaltechAUTHORS:20090805-152312511
Year: 1952
The chemical propellants form a special class of compounds. Some of the members of this class are usually not considered as being important enough to warrant special discussion in chemistry courses. For this reason it appears to be of interest to present a catalogue of representative chemicals with emphasis on the particular characteristics which make them useful or usable rocket propellants.https://resolver.caltech.edu/CaltechAUTHORS:20090805-152312511The emission of radiation from diatomic gases. III. Numerical emissivity calculations for carbon monoxide for low optical densities at 300°K and atmospheric pressure
https://resolver.caltech.edu/CaltechAUTHORS:20090805-142635076
Year: 1952
DOI: 10.1063/1.1702185
Numerical emissivity calculations at 300°K and atmospheric pressure for nonoverlapping rotational lines have been carried out for CO using a dispersion formula for the line-shape representation. Use of the best available experimental data on integrated absorption and rotational line-width leads to calculated emissivities which are in excellent agreement with extrapolated empirical data published by Hottel and Ullrich. In particular, the theoretical dependence of emissivity on optical density, for small optical densities at 300°K, has been shown to follow experimental observations with satisfactory precision.For small optical densities the calculated emissivity is found to be proportional to the square root of the assumed rotational line-width, thus emphasizing the need for accurate line-width determinations at elevated temperatures. The limits of validity of the treatment utilizing nonoverlapping rotational lines are defined by examining overlapping between adjacent weak and strong rotational lines.The calculation of emissivities can be simplified by the use of approximate treatments. Thus absolute values of the emissivity can be predicted within 10 percent by utilizing a treatment for nonoverlapping, equally spaced, and equally intense lines, together with empirically determined values for the equivalent mean integrated absorption of the rotational lines of CO. A better analytic solution, which does not involve the assumptions of equal spacing and equal intensity of the rotational lines, has been obtained by utilizing asymptotic relations for large values of modified Bessel functions.https://resolver.caltech.edu/CaltechAUTHORS:20090805-142635076Note on the application of near-frozen flow criteria for one-dimensional nonviscous expansion through a Laval nozzle
https://resolver.caltech.edu/CaltechAUTHORS:20090805-145128570
Year: 1952
DOI: 10.1063/1.1700409
A general criterion for near-frozen adiabatic expansion in one-dimensional nonviscous flow through a Laval nozzle has been described in a recent publication [1]. Unfortunately it appears that the discussion was so condensed that it is hardly possible to apply the results, Eq. (28a), without a few explanatory remarks.https://resolver.caltech.edu/CaltechAUTHORS:20090805-145128570Emission and absorption of radiation by spectral lines with Doppler contour
https://resolver.caltech.edu/CaltechAUTHORS:20090805-134446096
Year: 1952
DOI: 10.1063/1.1700447
Equations are developed for observable intensities in emission and absorption for spectral lines with Doppler contour. It is shown that the theoretical relations which are usually employed in estimating effective temperatures of internal energy states (a) require slight modifications when proper allowance is made for the shape of spectral lines, and (b) are not valid unless the product of spectral absorption coefficient and optical density is sufficiently small. Illustrative calculations on several spectral lines belonging to the (0,0) band of the 2Sigma-->2Pi band system of OH suggest that the conditions under which the basic relations hold are probably not satisfied for representative combustion flames.https://resolver.caltech.edu/CaltechAUTHORS:20090805-134446096On the kinetics of evaporation
https://resolver.caltech.edu/CaltechAUTHORS:20091209-112654154
Year: 1952
DOI: 10.1021/j150496a015
The kinetics of evaporation of liquids has been reconsidered from the point of view of classical kinetic reactions and also by application of the theory of absolute reaction rates. It is shown that evaporation treated as a unimolecular rate process, with a rate proportional to the surface concentration of energetic molecules, leads to the Knudsen equation for spherical molecules provided 6 square terms contribute to the energy of activation. As was pointed out in an earlier publication, the theory of absolute reaction rates, after correction for lack of equilibrium between normal molecules and the activated complex, leads to the Knudsen equation for spherically symmetric molecules if reasonable assumptions are made concerning the nature of the activated complex. Evidence is presented in support of the idea that the equilibrium theory of absolute reaction rates is not consistent with the model of the liquid used to determine evaporation rates. The theoretical treatment is next extended to polar liquids with restricted rotation and it is shown that the evaporation coefficient should be identified with the free-angle ratio, a conclusion which has been verified quantitatively by Wyllie.https://resolver.caltech.edu/CaltechAUTHORS:20091209-112654154On the Determination of Rotational Line Half-Widths of Diatomic Molecules
https://resolver.caltech.edu/CaltechAUTHORS:20091209-141443391
Year: 1952
DOI: 10.1063/1.1700578
A simple closed-form expression is obtained for the fractional intensity of radiation absorbed by vibration-rotation bands with collision-broadened spectral lines. The resulting expressions greatly reduced the labor involved in obtaining apparent rotational half-widths from experimental measurements.https://resolver.caltech.edu/CaltechAUTHORS:20091209-141443391On the Validity of Anomalous Population Temperatures in Flames
https://resolver.caltech.edu/CaltechAUTHORS:20091210-140920447
Year: 1952
DOI: 10.1063/1.1700694
It should be obvious to anyone reading our recent papers objectively that our "principle thesis" was (a) to examine the origin of the basic relations involved in the customary procedure for the determination of population temperatures in flames, with emphasis on the effect of spectral line shape on the final equations, and (b) to present experimental data on low pressure combustion flames which support the earlier experimental findings of Gaydon and Wolfhard.https://resolver.caltech.edu/CaltechAUTHORS:20091210-140920447A Two-Path Method for Eliminating the Effects of Self-Absorption on Temperature for Isothermal Flames
https://resolver.caltech.edu/CaltechAUTHORS:20091211-092800465
Year: 1952
DOI: 10.1063/1.1700756
It is the purpose of the current note to outline a two-path method for the determination of flame temperatures. The method is valid for isothermal systems and spectral lines with Doppler contour. All errors arising from self-absorption are eliminated. Practical applications are made by determining the ratio of the total intensity observed when the flame is viewed with a cool blackbody as background to the total intensity obtained with a cool mirror as background.https://resolver.caltech.edu/CaltechAUTHORS:20091211-092800465The Emission of Radiation from Diatomic Gases. IV. Emissivity Calculations for CO and HCl for Nonoverlapping Rotational Lines as a Function of Temperature and Optical Density
https://resolver.caltech.edu/CaltechAUTHORS:20091211-094656109
Year: 1952
Simplified expressions have been developed for the engineering emissivity of uniformly distributed diatomic gases for nonoverlapping rotational lines with a resonance contour. Unfortunately the rotational half-widths for spectral lines arising from transitions between excited vibrational energy levels are generally not known. For this reason it was necessary to make the assumption that the rotational half-widths for transitions of the form n-->n+v, v=1 or 2, are identical. The theoretical analysis is, however, sufficiently general to be useful without modification when accurate data concerning the dependence of line-width on vibrational excitation become available. Explicit expressions have been obtained for the contributions to the total emissivity associated with individual vibration-rotation bands.
Representative emissivity calculations have been carried out for CO and HCl. Comparison of the calculated emissivities of CO with experimental data shows only fair agreement, suggesting either that the assumed description of rotational half-widths is inadequate or else that the empirical emissivity data are not reliable at elevated temperatures.https://resolver.caltech.edu/CaltechAUTHORS:20091211-094656109Experimental Evidence for Anomalous Population Temperatures of OH in Flames
https://resolver.caltech.edu/CaltechAUTHORS:20091211-093848025
Year: 1952
DOI: 10.1063/1.1700748
It is the purpose of this note to present an evaluation of the
experimental evidence for and against "anomalous" temperatures
of OH in flames. Experimental studies have been carried out
on low pressure flames, and on flames burning at atmospheric
pressure. The results have usually been interpreted by using
relations which are applicable only to isothermal systems. Attempts
to correct for self-absorption have been made by using
isointensity methods. For spectral lines with Doppler contour
it has been demonstrated by quantitative calculations that the
isointensity methods do not correct for self-absorption unless
self-absorption is weak. In particular, Shuler's method, without
allowance for the effect of frequency on intensity, has been shown
to yield nonlinear plots for strong self-absorption and to be
inferior to conventional procedures in the absence of self-absorption.
Extensive studies on the effect of self-absorption in falsifying
experimental data have been carried out by Cowan and Dieke.
We have recently attempted to estimate absolute emission intensities
for OH in low pressure flames by using data obtained
by Oldenberg and Rieke.https://resolver.caltech.edu/CaltechAUTHORS:20091211-093848025Emissivity for CO_2 at Elevated Pressures
https://resolver.caltech.edu/CaltechAUTHORS:20091214-131602254
Year: 1952
DOI: 10.1063/1.1702060
Total absorptivity measurements have been carried out at room temperature as a function of partial pressure of CO_2 and of total pressure using nitrogen as pressurizing gas.https://resolver.caltech.edu/CaltechAUTHORS:20091214-131602254Quantitative Studies of Apparent Rotational Temperatures of OH in Emission and Absorption (Spectral Lines with Doppler Contour)
https://resolver.caltech.edu/CaltechAUTHORS:20091214-164334316
Year: 1953
DOI: 10.1063/1.1698618
Even if a Boltzmann distribution exists for the population of molecules in various energy levels, it is not possible to obtain a satisfactory interpretation of experimental data by the use of conventional procedures unless the product of maximum spectral absorption coefficient P_(max) and optical density χ is sufficiently small. Detailed calculations are presented which show that the experimental results, which suggest an anomalous rotational temperature for the ^2Σ state of OH in low pressure combustion flames, can be accounted for by using sufficiently large values for P_(max)χ (Sec. II). Whether or not experimental data should be interpreted in this manner must be determined by auxiliary studies.
Representative absorption studies for the determination of rotational temperatures in isothermal systems have been analyzed for the P_1 branch, (0,0) band, ^2π-->^2Σ transitions of OH at 3000°K. The calculations show that erroneous interpretation of experimental results occurs if the product P_(max)χ is not small compared to unity. Sample calculations for a blackbody light source show that the customary procedure for treating experimental results will permit adequate correlation of the data by straight lines up to relatively large values for P_(max)χ. It is remarkable that the preceding statement remains true even under conditions in which emission data clearly indicate that P_(max)χ is no longer small compared to unity (Sec. III).
Representative calculations to determine observable peak and total intensity ratios in emission for spectral lines with Doppler contour have been carried out for ^2Σ-->^2π transitions, (0,0) band, P_1 branch of OH at 3000°K. The calculations show that the ratios of peak and total intensities are functions of the products of maximum absorption coefficients (P_(max)) and optical density (χ) for the lines under study (Sec. IV).
Quantitative calculations have been carried out of apparent rotational temperatures in systems containing nonequilibrium distributions of OH at 3000°K and at 6000°K. The calculations on the P_1 branch, ^2Σ-->^2π transitions, indicate that, in the absence of self-absorption, conventional plots showing discontinuities necessarily overestimate one and underestimate the other of the known temperatures of 3000°K and 6000°K (Sec. V).
Quantitative calculations on the nature of distortions produced when an isothermal region at 3000°K is viewed through an isothermal region at 1500°K show that the presence of a non-isothermal field of view magnifies the distortion produced by self-absorption alone (Sec. VI).
On the basis of the noncontroversial quantitative calculations described in Secs. II to VI for idealized systems, some speculations regarding the significance of reported flame temperature anomalies for OH are presented in Sec. VII.https://resolver.caltech.edu/CaltechAUTHORS:20091214-164334316Determination of Absolute ƒ Values from Relative Intensity Measurements for Spectral Lines with Doppler Contour
https://resolver.caltech.edu/CaltechAUTHORS:20091215-085513442
Year: 1953
DOI: 10.1364/JOSA.43.0218_1
The experimental determination of absolute intensities for isolated spectral lines or for entire vibration-rotation bands involves formidable experimental difficulties. For this reason it is highly desirable to consider the use of techniques which permit the determination of absolute f values from relative intensity measurements performed by the use of a low resolution spectrograph. It is the purpose of this note to call attention to a useful experimental procedure for spectral lines with Doppler contour and for optical densities which are sufficiently large to assure a nonlinear dependence of intensity on optical density. The method is a generalization of a two-path experiment proposed for emission studies on flames.https://resolver.caltech.edu/CaltechAUTHORS:20091215-085513442On Maximum Evaporation Rates of Liquid Droplets in Rocket Motors
https://resolver.caltech.edu/CaltechAUTHORS:20091215-123319557
Year: 1953
Upper limits have been estimated for the rate of evaporation of small liquid droplets in representative rocket combustion chambers. The droplets are assumed to be
isothermal at all times. The droplet temperature as a function of time is determined by an appropriate heat balance. The calculations are useful in determining the significance of inelastic collisions between liquid droplets for complete combustion. Radiant heat transfer to moving liquid droplets is considered briefly.https://resolver.caltech.edu/CaltechAUTHORS:20091215-123319557Effect of Spectral Line Shape on Apparent Rotational Temperatures of OH
https://resolver.caltech.edu/CaltechAUTHORS:20091215-130819123
Year: 1953
DOI: 10.1063/1.1698990
The effect of spectral line shape on apparent rotational temperatures of OH has been investigated for the P_1 branch, ^2Σ-->^2π transitions, (0, 0) band, by treating the ratio of collision half-width to Doppler half-width as a variable parameter. The results of calculations for emission experiments, using conventional plots, show a large effect of line shape on apparent temperature. In general, the greater the ratio of collision half-width to Doppler half-width, the smaller the distortion of experimental data. The analysis predicts higher apparent rotational temperatures for isothermal systems at reduced pressures than at atmospheric pressures. Although this result is in agreement with experimental observations on flames, it cannot be used as an explanation for the observed data without auxiliary studies proving that distortion of data is of importance in any given case. The two-path method for determining temperatures and emissivities (concentrations) in flames has been extended to spectral lines with combined Doppler- and collision-broadening.https://resolver.caltech.edu/CaltechAUTHORS:20091215-130819123Nomogram for the Evaluation of Blackbody Radiancy and of Peak and Total Intensities for Spectral Lines with Lorentz Contour
https://resolver.caltech.edu/CaltechAUTHORS:20091215-104935690
Year: 1953
DOI: 10.1364/JOSA.43.000383
A nomogram has been constructed for the determination of blackbody radiancy and of peak and total intensities for spectral lines with Lorentz contour. The basic equations used for the construction of the nomogram and the use of the nomogram are described briefly.https://resolver.caltech.edu/CaltechAUTHORS:20091215-104935690Radiation from Isolated Spectral Lines with Combined Doppler and Lorentz Broadening
https://resolver.caltech.edu/CaltechAUTHORS:20091215-113204848
Year: 1953
DOI: 10.1364/JOSA.43.000385
Methods for the calculation of spectral absorption coefficients for combined Doppler and Lorentz broadening are summarized. The "curves of growth" have been extended to cover the ranges of parameters which arise in spectroscopic studies on flames.https://resolver.caltech.edu/CaltechAUTHORS:20091215-113204848Optical Methods for the Determination of Combustion Temperatures
https://resolver.caltech.edu/CaltechAUTHORS:20091215-125945046
Year: 1953
A brief survey is presented of optical methods for the determination of temperatures which can be used in rocket engines. The data are presented in outlines and include an outline of basic principles involved in application of a given technique, a sketch of the experimental arrangement, and key references which should he consulted for further details.https://resolver.caltech.edu/CaltechAUTHORS:20091215-125945046Nomogram for the Evaluation of Blackbody Radiancy and of Peak and Total Intensities for Spectral Lines with Doppler Contour
https://resolver.caltech.edu/CaltechAUTHORS:20091215-110238137
Year: 1953
DOI: 10.1364/JOSA.43.000380
A nomogram has been constructed for the determination of blackbody radiancy and of peak and total intensities for spectral lines with Doppler contour. The basic equations used for the construction of the nomogram and the use of the nomogram are described briefly. A method is outlined for determining absolute values of total intensities for spectral lines with combined Doppler and resonance contour by using the nomogram in conjunction with the "curves of growth."https://resolver.caltech.edu/CaltechAUTHORS:20091215-110238137Effects of Temperature Gradients, Self-Absorption, and Line Shape on Apparent Rotational Temperatures of OH
https://resolver.caltech.edu/CaltechAUTHORS:20091222-143729042
Year: 1954
The effect on apparent rotational temperatures (of OH) of adjacent radiating and absorbing regions at different temperatures and of spectral line shape, coupled with varying degrees of self-absorption, has been studied. The calculations emphasize the fact that definitive conclusions regarding interpretation of flame spectra are difficult to obtain by use of conventional low-resolution spectroscopic studies of flames. Multiple path experiments, or absorption studies with a discrete line source, appear promising provided they are restricted to conditions under which the spectral line shape is known.https://resolver.caltech.edu/CaltechAUTHORS:20091222-143729042Approximate Emissivity Calculations for Polyatomic Molecules. I. CO_2
https://resolver.caltech.edu/CaltechAUTHORS:20100622-165045361
Year: 1954
DOI: 10.1063/1.1721706
Approximate emissivity calculations for CO_2 have been carried out, as a function of optical density, at 300 and at 600°K. The calculations involve the assumption that the rotational lines overlap extensively. This condition appears to be satisfied at total pressures above about 1 atmos. Comparison of the values calculated from spectroscopic data with the emissivities tabulated by Hottel and his collaborators shows satisfactory agreement. The analysis presented in this manuscript emphasizes the fact that it is possible to obtain reasonable estimates for the engineering emissivity without performing extensive analytical work, provided the physical principles are understood and the needed spectroscopic data are available.https://resolver.caltech.edu/CaltechAUTHORS:20100622-165045361On the burning of single drops of fuel in a oxidizing atmosphere
https://resolver.caltech.edu/CaltechAUTHORS:20110120-093347600
Year: 1954
A simplified model for the process of steady burning of a
stationary droplet of fuel in an oxidizing atmosphere has
been examined. Explicit expressions have been obtained
for the burning rate of the fuel droplet, for the temperature at the flame front, and for the radius of the combustion surface. The principal assumptions on which our analysis is based are: the flame front is established at a spherical
surface surrounding the drop; the rates of delivery
of fuel and oxygen to this surface are in stoichiometric
proportions; the rates of reaction at the flame front are
fast compared to the rates of delivery of combustible gases.
Our analysis is an extension and generalization of the work
of G. A. E. Godsave. We are able to delete several of Godsave's restrictive assumptions by use of an efficient method for formulating the problem in which only integrated
forms appear for the expressions of conservation of mass
and energy. Our theoretical formulas provide a satisfactory
correlation of Godsave's experimental results.https://resolver.caltech.edu/CaltechAUTHORS:20110120-093347600Combustion problems in liquid-fuel rocket engines
https://resolver.caltech.edu/CaltechAUTHORS:20110131-082519111
Year: 1955
DOI: 10.1016/S0082-0784(55)80009-4
No abstracthttps://resolver.caltech.edu/CaltechAUTHORS:20110131-082519111Experimental determination of rotational temperatures and concentrations of OH in flames from emission spectra
https://resolver.caltech.edu/CaltechAUTHORS:20110118-134330601
Year: 1955
DOI: 10.1063/1.1740513
In order to illustrate the use of two‐path experiments for correcting for self‐absorption, experimental studies to determine the rotational "temperatures" and concentrations of OH in flames burning at atmospheric pressure have been carried out. For mixtures of H_2, C_2H_2, and O_2, as well as for C_2H_2-O_2 flames diluted with A, "anomalous" rotational "temperatures" were observed under conditions in which strong self‐absorption was clearly indicated by the intensity ratios for the double‐path to the single‐path experiments. Unequivocal quantitative estimates of rotational temperatures and of OH concentrations cannot be carried out, even on the assumption that the emitting system is isothermal and in equilibrium. However, by using the results of theoretical studies on two‐path experiments carried out by one of us, it is possible to obtain reasonable upper limits for the temperatures and lower limits for the OH‐concentrations, based on an assumed Doppler contour for the line‐shape and utilizing Oldenberg's estimates for the f values of representative spectral lines. Our experimental studies lead to reasonable rotational temperatures at the tip of luminous cones for mixtures of H_2, C_2H_2, and O_2 and for C_2H_2-O_2 flames diluted with up to 60 percent argon. These observations do not disprove the reality of rotational temperature anomalies in the inner cones of flames. Significant improvement of experimental procedure, and quantitative interpretation of results along the lines used by us, requires additional basic studies with emphasis on the measurement of spectral line‐shape and absolute intensitieshttps://resolver.caltech.edu/CaltechAUTHORS:20110118-134330601Invariance of integrated transmittance and total fractional transmission with experimental slit function
https://resolver.caltech.edu/CaltechAUTHORS:20110119-101940015
Year: 1955
DOI: 10.1063/1.1742104
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110119-101940015On the determination of absolute intensities from single- and multiple-path absorption measurements
https://resolver.caltech.edu/CaltechAUTHORS:20110119-112148460
Year: 1955
DOI: 10.1063/1.1740731
The physical principles involved in conventional absolute intensity measurements are reviewed. Experimental
difficulties rule out the use of extrapolation techniques for some spectral transitions. For this reason it is of interest to re-examine the possibility of using total absorption measurements, in conjunction with the curves of growth, for making intensity estimates. Extrapolation methods yield results which are independent of spectral line shape. Use of the curves of growth, on the other hand, implies the assumption that the line contour can be described by combined Doppler and Lorentz broadening.
The curves of growth permit a unique correlation between total absorption and f-value either for spectral lines with pure Doppler broadening or for pure collision broadening. Furthermore, a simple experimental procedure can be devised for estimating both the absolute intensity and the spectral line profile on the basis of single-path and multiple-path absorption measurements. The suggested procedure involves absorption' measurements for optical densities (path lengths) under conditions in which the integrated fractional absorption is a relatively sensitive function of spectral line shape. Representative calculations referring to utilization of the proposed method have been carried out for spectral lines belonging to the ^2∑→^2II transitions, (0,0)-band, of OH, and also for lines belonging to the fundamental vibration-rotation spectrum of CO.https://resolver.caltech.edu/CaltechAUTHORS:20110119-112148460Interference effects during burning in air for stationary n-heptane, ethyl alcohol, and methyl alcohol droplets
https://resolver.caltech.edu/CaltechAUTHORS:20110114-142438756
Year: 1956
Experiments have been conducted for the determination
of the evaporation constant and flame shapes of two and
of five closely spaced droplets burning in air. Droplets of
approximately the same and of different diameters were
used at various distances between the droplet centers.
The apparent flame shape, which was observed only for n-heptane droplets, changes very little during burning.
The square of the droplet diameter decreases linearly with
time for fixed spacing between droplet centers, at least
within the experimental limits of accuracy. In general,
the average evaporation constant for two droplets, K',
must be assumed either to vary continuously during burning
or else to be a function of average initial drop diameter,
D^0. The change of K' with time corresponds to the second
derivative in plots of the square of the diameter vs. time.
These second derivatives are not defined in our work because
of unavoidable scatter of the experimental data. Attempts at understanding the observed results by considering
published theories for single droplets, as well as groupings obtained from dimensional analysis, have been
unsuccessful. It appears that the diffusion model for
the heterogeneous burning of single fuel droplets will require serious revision and extension before the burning of
droplets arrays and sprays can be understood quantitatively.
Furthermore, the effective value of K' for a spray
probably depends not only on the fuel-oxidizer system but
also on the injection pattern. For this reason additional
studies had best be carried out under conditions corresponding to those existing in service models.https://resolver.caltech.edu/CaltechAUTHORS:20110114-142438756Multiple-path technique for the determination of physico-chemical data behind shock fronts
https://resolver.caltech.edu/CaltechAUTHORS:20110118-101201095
Year: 1956
DOI: 10.1063/1.1743123
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110118-101201095On the development of rational scaling procedures for liquid-fuel rocket engines
https://resolver.caltech.edu/CaltechAUTHORS:20110113-134244485
Year: 1957
A critical summary is presented of recent theoretical
studies concerning similarity analysis and the scaling of
liquid-fuel rocket engines. On the basis of this work,
some suggestions are offered for an experimental program
which has as its objective the development of rational
scaling procedures.https://resolver.caltech.edu/CaltechAUTHORS:20110113-134244485Absolute intensities for the ultraviolet γ bands of NO
https://resolver.caltech.edu/CaltechAUTHORS:20110113-140209278
Year: 1957
DOI: 10.1063/1.1743421
Absolute intensities have been measured for three of the ultraviolet γ bands of NO. The corresponding electronic absorption oscillator strength is estimated to be 0.0024±0.0004.https://resolver.caltech.edu/CaltechAUTHORS:20110113-140209278On excess enthalpy, flame extinction and minimum ignition energies
https://resolver.caltech.edu/CaltechAUTHORS:20110113-144556140
Year: 1957
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110113-144556140Infrared emissivities and absorptivities of gases
https://resolver.caltech.edu/CaltechAUTHORS:20110113-141408696
Year: 1957
DOI: 10.1063/1.1722813
Approximate analytic expressions are obtained for the "effective band widths" and emissivities of diatomic molecules at elevated pressures. The absorptivities of molecular vibration‐rotation bands are evaluated for radiation emitted by similar molecular vibration‐rotation bands and for radiation emitted by blackbodies. The results obtained for the absorptivity calculations compare favorably with available empirical correlations for H_2O. The postulated model does not apply to CO_2 and, therefore, no satisfactory theoretical formula has been derived for the absorptivities of this molecule. The appendix (by A. Thomson) is devoted to a critical examination of the limits of validity of the effective band‐width concept for different molecules.https://resolver.caltech.edu/CaltechAUTHORS:20110113-141408696Recent studies on flame stabilization of premixed turbulent gases
https://resolver.caltech.edu/CaltechAUTHORS:20110203-143842451
Year: 1957
FLAME stabilization is of importance in the practical design
of ramjets and afterburners. It has been studied
extensively in recent years, particularly with reference to
bluff-body flame-holders. In the present survey we describe
the investigations relating to flame holding by bluff bodies as well as new techniques (e.g.,. flame holding by the use of reverse jets) which may prove to be of practical importance in new engine configurations. In Section II we consider the flow field downstream of a bluff-body flame-holder which includes the recirculation zone behind the body and a region of flame spreading farther downstream.
Explicit reference is made to crucial experiments which illustrate the nature and magnitude of the velocity field, the physical extent, the temperature, and the gas composition of the recirculation zone. Experimental studies and theoretical predictions of the angle of flame spreading, as well as some observations on unstable flow and the onset of blowoff, will be reviewed.
The variation of blowoff velocity with flame-holder design,
pressure, and mixture composition is considered briefly in
Section III both for single and for adjacent bluff bodies. Also included is a summary of results for blowoff velocities obtained with a reverse-jet flame-holder and with wall recesses. Theoretical studies on the mechanism of flame stabilization form the subject of Section IV. We shall indicate the points on which various proposed models agree and disagree with experiment and attempt to formulate a composite description which is consistent with most of the currently available experimental data both for bluff-body and for reverse-jet flameholders.https://resolver.caltech.edu/CaltechAUTHORS:20110203-143842451On generalized scaling procedures for liquid-fuel rocket engines
https://resolver.caltech.edu/CaltechAUTHORS:20110118-105514911
Year: 1957
DOI: 10.1016/0010-2180(57)90049-4
The scaling procedures of Penner and Tsien, of Crocco and of Barrère have been generalized by using the assumption that the mean drop size is proportional to the product of powers of the Weber number and the Reynolds number, together with the hypothesis that the total conversion time varies as a power (usually the second) of the drop diameter. The results obtained for the steady aero thermochemistry and for unstable motor operation (low-frequency and high-frequency oscillations) are
shown to reduce to previously published rules when suitable simplifying assumptions are made.https://resolver.caltech.edu/CaltechAUTHORS:20110118-105514911Heterogeneous burning in a diverging reactor
https://resolver.caltech.edu/CaltechAUTHORS:20110121-094732263
Year: 1959
DOI: 10.1016/0010-2180(59)90038-0
Experimentally determined pressure profiles in a diverging reactor have been used to estimate effective mean drop diameters and size distributions at the injector end. The available results may be correlated in terms of two simplified models using (a) a uniform mean drop size for the spray and (b) a generalized size distribution of the Rosin-Rammler type. Mean drop sizes of the order of 5 to 10 microns, and effective overall reaction orders between ⅓ and 2 are obtained if the phenomenological burning rate law familiar from single droplet studies is used for heterogeneous burning in bipropellant LOX-RP1 mixtures.https://resolver.caltech.edu/CaltechAUTHORS:20110121-094732263Relation between gas absorptivities and emissivities
https://resolver.caltech.edu/CaltechAUTHORS:20110113-073257572
Year: 1959
DOI: 10.1063/1.1734963
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110113-073257572The conservation equations for independent coexistent continua and for multicomponent reacting gas mixtures
https://resolver.caltech.edu/CaltechAUTHORS:20110125-094239088
Year: 1959
The equations for conservation of mass, momentum, and energy are derived for a set of independent, coexistent continua obeying the laws of dynamics and thermodynamics. The idea of a control volume and a control surface for each continuum is used in the analysis. The derived results are practically identical with relations obtained previously by Th. von Kármán. A direct comparison is conducted between the continuum theory results and those obtained from kinetic theory by assuming that, for each of the species, the kinetic theory definitions apply. It is found that the new terms appearing in the conservation equations derived from continuum theory are precisely those which are required to make these equations identical with the results obtained from the kinetic theory of multicomponent, reacting gas mixtures. However, the continuum theory forms of the equations are not useful because they require knowledge of the transport properties for individual species in the mixture.https://resolver.caltech.edu/CaltechAUTHORS:20110125-094239088Radiant energy emission from excited harmonic oscillators
https://resolver.caltech.edu/CaltechAUTHORS:20110111-142123659
Year: 1960
DOI: 10.1063/1.1730752
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110111-142123659Oscillator strengths of the ultraviolet γ bands of NO
https://resolver.caltech.edu/CaltechAUTHORS:20110111-150128667
Year: 1960
DOI: 10.1364/JOSA.50.000627
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110111-150128667Combustion and flames
https://resolver.caltech.edu/CaltechAUTHORS:20110105-105940018
Year: 1960
DOI: 10.1146/annurev.pc.11.100160.002135
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110105-105940018Radiant energy emission from the equilibrated reaction products of a upre ammonium perchlorate pellet
https://resolver.caltech.edu/CaltechAUTHORS:20110110-115025686
Year: 1961
DOI: 10.1016/S0082-0784(06)80515-1
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110110-115025686An iterative procedure for the solution of nozzle-relaxation problems with reversible chemical reactions
https://resolver.caltech.edu/CaltechAUTHORS:20110110-112613040
Year: 1961
DOI: 10.1016/S0082-0784(06)80524-2
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110110-112613040Flame propagation in liquid-fuel droplet arrays
https://resolver.caltech.edu/CaltechAUTHORS:20110110-095214561
Year: 1961
DOI: 10.1016/S0082-0784(06)80602-8
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110110-095214561The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions
https://resolver.caltech.edu/CaltechAUTHORS:20110111-093335267
Year: 1961
The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions. The present status of the theory of one-dimensional, steady, laminar flame propagation for one-step chemical reactions is reviewed with particular emphasis on methods of solution and on the physical processes that dominate observable results.https://resolver.caltech.edu/CaltechAUTHORS:20110111-093335267Approximate infrared emissivity calculations for HCl at elevated temperatures
https://resolver.caltech.edu/CaltechAUTHORS:20110106-072930687
Year: 1961
DOI: 10.1364/JOSA.51.000460
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110106-072930687On iraser detectors for radiation emitted from diatomic gases and coherent infrared sources
https://resolver.caltech.edu/CaltechAUTHORS:20110111-105512909
Year: 1961
DOI: 10.1016/0022-4073(61)90021-8
The principles involved in the construction of a detector based on the use of an infrared maser (i.e., an iraser) are described for diatomic molecules. The use of iraser detectors holds promise for increasing detector sensitivity over more conventional detector devices for a selected number of diatomic emitters, namely, for molecules with relatively distant rotational line spacing such as HCl or HF. The iraser device may also be used as a multi-wavelength, coherent infrared sourcehttps://resolver.caltech.edu/CaltechAUTHORS:20110111-105512909Influence of Heterogeneous Reaction Processes on Atomic Recombination Rates in Rocket Nozzles
https://resolver.caltech.edu/CaltechAUTHORS:20110106-153626736
Year: 1962
Approximate relations are derived for determining under what
conditions in two-phase flow heterogeneous two-body processes are expected to proceed as rapidly as the homogeneous three-body recombination reaction.https://resolver.caltech.edu/CaltechAUTHORS:20110106-153626736Experimental determination of the heat of dissociation of N _2O_4→2NO_2 from the temperature dependence of absolute infrared intensities
https://resolver.caltech.edu/CaltechAUTHORS:20110111-133201065
Year: 1962
DOI: 10.1063/1.1732326
The heat of dissociation of N_2O_4 has been determined from measurements of the temperature dependence of the integrated absorption of NO_2 and N_2O_4 vibration-rotation bands. Results have been obtained that are in acceptable accord with the earlier estimate of Giauque and Kemp.https://resolver.caltech.edu/CaltechAUTHORS:20110111-133201065Approximate spectral absorption coefficient calculations for electronic band systems belonging to diatomic molecules
https://resolver.caltech.edu/CaltechAUTHORS:20110111-140517033
Year: 1962
DOI: 10.1016/0022-4073(62)90002-X
The spectral absorption coefficients in electronic band systems of diatomic emitters have been computed in the past by models that may be described as 'the just overlapping line model' and a model 'utilizing a smeared out rotational structure'. Although the basic relations are obtained by utilizing somewhat different physical arguments, the resulting equations are, in fact, identical. Spectral absorption coefficients have been calculated for the NO γ-bands at 2000ºK by using the approximate theoretical relations. The calculated results are in good agreement with estimates derived by numerical calculations in which, however, the absorption coefficient data were averaged over intervals of 2000 cm^(-1).https://resolver.caltech.edu/CaltechAUTHORS:20110111-140517033Propellants and Combustion
https://resolver.caltech.edu/CaltechAUTHORS:20110204-072536822
Year: 1962https://resolver.caltech.edu/CaltechAUTHORS:20110204-072536822Radiative energy transfer to centrally located areas in cylindrical and conical chambers containing isothermal, grey emitters
https://resolver.caltech.edu/CaltechAUTHORS:20110106-133056508
Year: 1963
DOI: 10.1016/0022-4073(63)90004-9
The geometrical interchange factors for radiative energy transfer have been evaluated for various conical configurations. A representative calculation has been carried out for the radiant energy transfer to a centrally located area element at the plane of intersection between two coaxial cones.https://resolver.caltech.edu/CaltechAUTHORS:20110106-133056508Combustion and Propulsion Research
https://resolver.caltech.edu/CaltechAUTHORS:20110106-080122631
Year: 1963
DOI: 10.1021/cen-v041n002.p074
Combustion chemistry is one of the oldest branches of chemical science. Among its pioneers must be counted Lavoisier, Bunsen, and others whose names belong among those of the founders of chemical science. That this close connection between combustion science and chemistry continues is well illustrated by the work of C. N. Hinshelwood and N. N. Semenov in elucidating chain reaction mechanisms, for which they shared the 1956 Nobel Prize. This work was at least partly motivated by difficulties in solving a classical problem in combustion science, viz., measurement of explosion limits for premixed gases in closed vessels.https://resolver.caltech.edu/CaltechAUTHORS:20110106-080122631On radiative transfer calculations from non-isothermal gases
https://resolver.caltech.edu/CaltechAUTHORS:20110104-110939383
Year: 1963
DOI: 10.1016/0022-4073(63)90041-4
N/Ahttps://resolver.caltech.edu/CaltechAUTHORS:20110104-110939383Experimental determination of desorption rates and of heats of desorption
https://resolver.caltech.edu/CaltechAUTHORS:20110104-113444432
Year: 1963
DOI: 10.1063/1.1710995
Gas discharge rates through a de Laval nozzle from a closed chamber have been measured for Ar, He, and CO_2. The effective desorption rates from vessels containing sand and silica gel have also been determined at various temperatures by measuring the time rate of pressure decay in the chamber. The experimental data have been used, in conjunction with a theoretical expression for diffusion controlled desorption rates, to estimate heats of desorption from silica gel. Results have been obtained
that are in approximate agreement with estimates made by other investigators using more conventional procedures.https://resolver.caltech.edu/CaltechAUTHORS:20110104-113444432Approximate Theoretical Calculation of Continuum Opacities
https://resolver.caltech.edu/CaltechAUTHORS:20110105-092119084
Year: 1964
DOI: 10.2514/3.2623
An approxhnate procedure is described for the theoretical calculation of the spectral absorption
coefficient produced by bound-free and free-free transitions in plasmas containing polyelectronic
atoms and ions. Our method of calculation is based on the assumption that only two ionized species make important contributions to the opacity and that these two ionic
constituents are present in equal concentrations. The approximate formulas are shown to yield results that are in good accord with estimates based on detailed numerical computations for nitrogen.https://resolver.caltech.edu/CaltechAUTHORS:20110105-092119084Transmission of infrared radiation through liquid water and through water vapor near saturation
https://resolver.caltech.edu/CaltechAUTHORS:20110104-140209282
Year: 1964
DOI: 10.1016/0022-4073(64)90077-9
No abstract is available for this article.https://resolver.caltech.edu/CaltechAUTHORS:20110104-140209282The near-infrared absorption of liquid water at temperatures between 27 and 209°C
https://resolver.caltech.edu/CaltechAUTHORS:20110105-081524276
Year: 1964
DOI: 10.1016/0022-4073(64)90005-6
The spectral absorption coefficients of liquid water have been measured between 2200 and 3000 cm^(-1) and between 3700 and 7600 cm^(-1) at temperatures of 27, 89, 159, and 209°C. The integrated intensities for the entire spectral regions extending from 4600 to 5900 cm^(-1) and from 5900 to 7600 cm^(-1) have also been determined at each of the specified temperatures. Following Buijs and Choppin, the experimental data have been used, in a highly simplified analysis, for the determination of hydrogen bonding
in liquid water on the assumption that water consists of clusters containing only zero, one or two hydrogen
bonds per molecule. We have also indicated briefly a more complete analysis of the experimental measurements
in which the full range of results on spectral absorption coefficients as a continuous function of frequency is properly utilized.https://resolver.caltech.edu/CaltechAUTHORS:20110105-081524276