Heat-transfer measurements with a catalytic flat plate in dissociated oxygen.

Golian, T. C.; Vidal, R. J.

doi:10.2514/3.4254

Cited by 14 publications

(5 citation statements)

References 33 publications

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“…h, is the chemical enthalpy associated with the dissociated species, ho is the stagnation enthalpy, a is the dissociation fraction, a is the Prandtl number, and E(x, a ) is directly related to the surface Damkohler number as follows since I n the non-catalytic wall limit, E -+ co and au,/a, = 1 which, for a = 1, reduces the Allowing for the different definitions of S and S', this result is seen to be similar to that of Vidal & Golian (1967) [equation ( 8 ) ] for the case when aJae + 0 (fully catalytic surface limit) except that the Prandtl number, u) and the density-viscosity product are more realistically evaluated a t conditions appropriate to the intermediate enthalpy.…”

Section: Prediction Of the Surface Heat-transfer Rates Including Surfmentioning

confidence: 70%

“…Glassy materials such as pyrex or quartz have values of y' of order whereas metallic surfaces generally have values up to 10-l. An experimental situation may therefore exist for which the values of cs for the different materials may differ by three orders of magnitude and in which almost all of the chemical enthalpy difference may be evident in the measured surface heat transfer rate. Vidal & Golian (1967) have reported an extension of Crocco's compressible laminar boundary-layer solution to include species diffusion for zero pressure gradient and with p a T", where a is a constant. The result for the dimensionless heat transfer rate S', is…”

Section: Prediction Of the Surface Heat-transfer Rates Including Surfmentioning

confidence: 99%

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Measurements of heat transfer to a flat plate in a dissociated high-enthalpy laminar air flow

1980

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Heat-transfer rates from a non-equilibrium hypersonic air flow to flat plates at zero and 12° incidence have been measured in a free piston shock tunnel at stagnation enthalpy levels up to 51 MJ kg−1. Nozzle flow conditions resulted in test section velocities up to 8·1 km 8−1 and in an experimental regime in which the free stream was chemically frozen and the flat-plate boundary layer was laminar. Estimates of the gas-phase and surface-reaction Damkohler numbers have been made and the heat-transfer results are discussed in this context. At the highest test-section densities non-equilibrium endothermic gas phase reactions involving oxygen atoms in the boundary layer are suggested as a possible mechanism for the observed low heattransfer rates.

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Section: Prediction Of the Surface Heat-transfer Rates Including Surfmentioning

confidence: 70%

Section: Prediction Of the Surface Heat-transfer Rates Including Surfmentioning

confidence: 99%

Measurements of heat transfer to a flat plate in a dissociated high-enthalpy laminar air flow

1980

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“…The latter is a minor problem since resetting of the overheat ratio is a simple and rapid manoeuvre. Protecting the films permanently from damage, particularly electrolytic etching, is best achieved by coating the film with silicon resinate during construction of the probe, using the technique described by Vidal & Golian (1967). The thickness of the layer obtained is of the order of 1 micron and has a negligible effect on the frequency response.…”

Section: Probpsmentioning

confidence: 99%

An experimental study of the velocity distribution and transition to turbulence in the aorta

1972

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The development and evaluation of a hot-film probe, suitable for use within arteries and operated with a commercial constant-temperature anemometer and linearizcr, is described. The performance of the system in the recording of arterial velocity wave forms is described, and instantaneous and time-averaged velocity profiles constructed from measurements in the thoracic aorta of dogs are presented. The profiles were blunt, with boundary layers estimated to be less than 2 mm thick throughout the cycle, and significant skews were observed, the explanation for which appears to lie in the influence of local geometry on the flow. A preliminary study of flow disturbances in the aorta based on visual observation of instantaneous velocity wave forms and frequency spectrum analysis is reported. The occurrence of flow disturbances and turbulence is shown to be related to peak Reynolds number and the frequency parameter α. The possible roles of free-stream disturbances and boundary-layer transition in generating these disturbances are discussed.

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“…In the shock tube, the first results on the influence of surface catalycity on heat transfer in dissociated oxygen flows were obtained in Ref. 25. The method of determining γ O and γ N in the case of a pulsed supersonic flow around the model in the shock tube and the results for quartz, ceramics, graphite, and silicized graphite were reported in Ref.…”

Section: Experimental Methods and Facilitiesmentioning

confidence: 99%

“…For high-catalytic surfaces, the data on the values of γ are contradictory, partly because the observed catalycity depends on the flow conditions around the surface. The best catalyst for catalytic recombination of oxygen atoms in the dissociated oxygen flow around cold surfaces (T w = 300 K) is silver [25,37]. In subsonic air and nitrogen flows, oxygen-free copper at p 0 = 0.1 atm and T w ∼ 300 K can be considered as a reference high-catalytic material [38]; in supersonic airflows, it can be considered as a material with moderate catalycity [39,40].…”

Section: Experimental Methods and Facilitiesmentioning

confidence: 99%

Chapter 6: Modeling of Catalytic Properties of Thermal Protection Coatings of Space Vehicles

2013

Hypersonic Aerodynamics and Heat Transfer

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The large practical interest in research of the interaction of multispecies gas mixtures with catalytic surfaces in supersonic flows was aroused by the development of reusable space vehicles, the Space Shuttle and Buran. For such vehicles, the use of low-catalytic coatings can ensure significant reduction of heat fluxes and, therefore, the weight of necessary thermal protection systems. Consequently, the payload can be increased. Laboratory and in-flight tests of experimental reusable systems-Bor, Buran, and Space Shuttle-showed that the use of low-catalytic coatings makes it possible to reduce heat fluxes to the vehicle surface by a factor of 3-5 [1][2][3][4][5].The interest in this problem was revived when the International Space Station was created and also due to the development of hypersonic transportation systems, such as NASP in the USA, Sanger in Germany, HOTOL in Great Britain, aerospace glider in Japan, and reentry vehicles such as the European mini-shuttle Hermes and the Japanese vehicle HOPE. The program of manned flights was also successfully developed in China. These projects gave rise to significant theoretical and experimental research all over the world. The efforts associated with the development of a rescue space vehicle for returning from the International Space Station in the case of emergency also increased the interest in effective thermal protection systems.A further impetus to future space transportation technologies is expected to be given by programs aimed at the development of hypersonic reusable flying vehicles. New problems in science and technology are also posed by projects of scientific expeditions to Mars, which can be realized in the near future.The development of promising aerospace vehicles requires solving, principally, new scientific and engineering problems. One of the most important problems is the development of a reusable thermal protection system. Calculations of thermal loads and predictions of the lifetime of a reusable thermal protection system require fundamental information

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Heat-transfer measurements with a catalytic flat plate in dissociated oxygen.

Cited by 14 publications

References 33 publications

Measurements of heat transfer to a flat plate in a dissociated high-enthalpy laminar air flow

Measurements of heat transfer to a flat plate in a dissociated high-enthalpy laminar air flow

An experimental study of the velocity distribution and transition to turbulence in the aorta

Chapter 6: Modeling of Catalytic Properties of Thermal Protection Coatings of Space Vehicles

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