Spectroscopic Studies of Highly Ionized Argon Produced by Shock Waves

Petschek, H. E.; Rose, P. H.; Glick, H. S.; Kane, Anne; Kantrowitz, Arthur

doi:10.1063/1.1721869

Cited by 105 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The high estimate in Kivel and Bailey was made intentionally to be consistent with a shock-tube measurement of the Kramer's radiation from argon. 11 The uncertainties in the theory used by Lindenmeier center around (1) the many atomic lines in the spectrum and (2) the suppression of the ionization potential by collisions in the high-temperature gas. Both these corrections increase the estimate made by Lindenmeier.…”

Section: Radiation From High-temperature Airmentioning

confidence: 99%

Radiation From Hot Air and Its Effect on Stagnation-Point Heating

Kivel

1961

Journal of the Aerospace Sciences

View full text Add to dashboard Cite

IntroductionThe heating of the stagnation region of a blunt body by radiation from the hot air in the shock layer is investigated for flight speeds up to 50,000 ft./sec. by using experimental shock-tube data, supplemented by theoretical estimates.Nonequilibrium effects which modify the radiation predictions at high altitudes (>30 miles) are pointed out. The radiation is compared with the aerodynamic heating and is found to be important at high velocities (> 30,000 ft./sec.) and low altitudes (<25 miles). For this flight regime the dominant radiation results from the capture of electrons by nitrogen ions. Symbols A c E h I k n N P a r R IT P a T V V W z = = = = = = = = = = = = = = = = = = = =area constant energy enthalpy radiated power per unit volume Boltzmann's constant 8.62 X 10~ integer particle density pressure heat transfer distance nose radius 3.1416 mass density 5.67 X 10~1 2 watts/cm. 2 deg. 4 temperature flight velocity volume weight effective electric charge ~5 ev./deg. aero. D irad. ST 0 CO = aerodynamic = drag = radiation species = radiation = stagnation region = sea level = free stream provided the trajectories, and C. Lindenmeier estimated the Kramer's radiation in high-temperature air.T HE PROBLEM of aerodynamic heat transfer at the stagnation point in dissociated air has been a subject of considerable interest in high-speed re-entry problems. 1 The literature deals with the conduction of energy through the boundary layer, taking into account the effects of diffusion and recombination of atomic species. Very little has been published 2 about the energy carried to the body by radiation from the high-temperature air outside the boundary layer. In this paper we apply recent shock-tube measurements of the emissivity of high-temperature air to the problem of estimating this radiative heat transfer. We compare radiation with aerodynamic heat transfer and find that radiation is dominant at high flight speeds and low altitudes.The radiation heat transfer to the nose of re-entering IRBM's and ICBM'S can be estimated using the results of shock-tube measurements. Until recently, this radiation was not predictable because the rate at which the molecular constituents of high-temperature air radiated was unknown. It was soon realized that nitric oxide was a potent possibility even though there is only a few per cent of NO present, because a relatively large fraction of these molecules can radiate. 3 This is not true of N2 which is more plentiful. On the other hand, 0 2 is strongly dissociated at high temperatures. As we will note below, it turns out that NO has a low rate of radiation 4 so that the radiation from air is not important in the ballistic-missile re-entry regime.Recent interest in higher re-entry speeds, such as might be encountered on a return from an elliptic orbit around Mars, 5 has revived the radiation heating problem. A theoretical study of this problem indicates that for high re-entry velocities and high performance, radiation heat transfer may be orders of magnitude greater than the aerodynam...

show abstract

Section: Radiation From High-temperature Airmentioning

confidence: 99%

Radiation From Hot Air and Its Effect on Stagnation-Point Heating

Kivel

1961

Journal of the Aerospace Sciences

View full text Add to dashboard Cite

show abstract

“…); common to the walls and diaphragms; and other sources such as pump oils, and cleaning materials and agents. Several of these impurities were also ^ound in shock tube experimentation 16 .…”

Section: B Measurement Of the Spectrogramsmentioning

confidence: 96%

Vacuum Ultraviolet Radiation in the Expansion Tube

Oertel¹

1972

View full text Add to dashboard Cite

The findings are presented of an optical survey of vacuum ultraviolet (VUV) radiation emitted from the shock layer of a 1-1/2" diameter sphere in hypersonic flows of air, argon, nitrogen and argonnitrogen mixtures. Free stream velocities of 17,000-20,000 ft/sec and densities corresponding to altitudes ^ 90,000 ft. were obtained in the BRL expansion tube facility; steady flow conditions prevailed over the model for about 75 ysec. The radiation was recorded on sensitized film down to a lower limit of 1100 Ä. The purpose of the survey was to explore the feasibility of using this facility to measure time and space resolved radiation of the non-equilibrium, vibrationally-excited N2 in the shock layer; part of this radiation is conjectured to ionize O2 ahead of the shock around a hypersonic vehicle, thus enhancing its radar signature. Methods and problems of measuring VUV from this shock layer are discussed.

show abstract

“…При заметной степени ионизации происходит сдвиг спектральных ли-ний и их уширенце, вызванное суще-ствованием электрических полей по-ложительных ионов (эффект Штарка). Оба явления могут при этом исполь-зоваться для оценки степени иониза-ции газа за ударной волной 42 . При изучении сплошного спект-ра воздуха в инфракрасной области с помощью ударной трубки были получены данные, приведенные на рис.…”

Section: изучение кинетики химических реакций с помощью ударных волнunclassified

Shock wave studies of the physical properties of gases

Soloukhin¹

1959

Usp. Fiz. Nauk

View full text Add to dashboard Cite

ВВЕДЕНИЕВ лабораторной практике физических и физико-химических исследо-ваний свойств различных газов при высокой температуре все более широкое применение находят методы, в которых используются ударные волны. Объясняется это не только возможностями получения таким способом высоких температур и давлений газа, но и значительной простотой газо-динамической схемы процесса, которая позволяет учесть влияние физико-химических превращений среды и получить, таким образом, интересующие нас сведения об особенностях термодинамически неравновесных процессов, вызванных нагревом газа в ударной волне.С помощью ударных волн можно не только изучать термодинамически равновесные состояния газа, но и следить за установлением равновесия во времени, т. е. исследовать кинетику таких неравновесных процессов, как диссоциация, высокотемпературное окисление газов, релаксационные процессы энергетического обмена между внутренними степенями свободы молекул, а также между электронами и положительными ионами вещества, находящегося в ионизованном состоянии.С целью получения наиболее точных сведений о состоянии газа в тече-ние коротких интервалов времени (10~6-10~4 сек) разрабатываются новые импульсные методы измерения температуры, плотности, давления, степени ионизации, испускательной и поглощательной способности, электропро-водности и других параметров газа на основе современных физических методов измерения этих величин.В настоящей статье будут рассмотрены лишь некоторые из многочи ·-ленных исследований, посвященных ударным волнам в газе. Мы ограни-чимся только вопросами установления термодинамического равновесия за фронтом ударных волн в различных газах и попутно коснемся некоторых, наиболее интересных, методических работ в этом направлении.По вопросу об особенностях сильных ударных волн, о внутренней структуре фронта ударной волны с учетом излучения и лучистого тепло-обмена мы отсылаем читателя к обстоятельному обзору Я. Б. Зельдовича и Ю. П. Райзера 1 , написанному авторами многих оригинальных работ, посвященных изучению сильных ударных волн. § 1. О ВЫБОРЕ МЕТОДА ПОЛУЧЕНИЯ И ИСПОЛЬЗОВАНИЯ УДАРНЫХ ВОЛН Изменение параметров газа за фронтом ударной волны задается газодинамической схемой исследуемого процесса, т. е. видом и формой ударной волны (одномерный скачок уплотнения, волна детонации, ударная волна, вызванная быстро летящим телом и т. п.), а также ее 10 УФН, т. LXVIII, вып. 3

show abstract

Spectroscopic Studies of Highly Ionized Argon Produced by Shock Waves

Cited by 105 publications

References 11 publications

Radiation From Hot Air and Its Effect on Stagnation-Point Heating

Radiation From Hot Air and Its Effect on Stagnation-Point Heating

Vacuum Ultraviolet Radiation in the Expansion Tube

Shock wave studies of the physical properties of gases

Contact Info

Product

Resources

About