Thermal Properties Of Gas Research Articles

Computing Thermal Properties of Natural Gas by Utilizing AGA8 Equation of State

In current study, an attempt has been made to develop a numerical method and a computer program to calculate the thermal properties of natural gas mixture such as enthalpy and internal energy in addition of the compressibility factor using AGA8 state equation. The method has been applied to a typical Iranian natural gas mixture to calculate the thermal properties of the gas. Finally, the developed program has been utilized to model single reservoir fast filling process of a typical natural gas vehicle on-board cylinder. The computed results have been compared with simulation results of same process (fast filling) in which the pure methane was acted as working fluid. The results show the similar trends and good agreements.

Photothermal Gas Analyzer for Simultaneous Measurements of Thermal Diffusivity and Thermal Effusivity

In this paper, we describe a new, simple, and fast photothermal method for simultaneous measurements of two important gas thermal properties: thermal diffusivity and thermal effusivity. The method consists essentially in combining a photoacoustic cell and a thermal wave pyroelectric cell enclosed in a single compact gas analyzer. The photoacoustic cell is kept filled with synthetic air and sealed. The pyroelectric cell is also filled with synthetic air, and after some warm up time, the synthetic air is exchanged to the gas of interest. It is shown that the analysis of the transient and saturation signals of both photoacoustic and pyroelectric cells is capable of measuring the thermal properties with an accuracy of 3%. This particular capability of performing simultaneously the measurements of thermal diffusivity and thermal effusivity allows us to carry on the complete characterization of the thermal properties of gases.

Thermal motion of carbon clusters and production of carbon nanotubes by gravity-free arc discharge

Thermal and diffusion properties of hot gas around a dc arc discharge under a gravity-free condition are investigated using a jet plane in order to improve the arc production of carbon clusters. Spherically symmetric temperature distribution of He gas around the arc plasma and monotonic slow expansion of the high-temperature region are observed. By means of the passive-type Mie scattering method, random slow diffusion of carbon clusters around the arc plasma is clearly observed under the gravity-free condition. This indicates that carbon clusters including single-walled carbon nanotubes are synthesized around the arc plasma where the He temperature is higher than 1000K. It is confirmed that large bundles of fatter single-walled carbon nanotubes are produced under the gravity-free condition.

Measurement of thermal properties of gases using an open photoacoustic cell as a sensor

An alternative photothermal technique for the measurement of thermal properties of gases is described. The proposed technique uses the open photoacoustic cell as a sensor. The gas sample is confined between two thin aluminum foils. One of these acts as the absorber of modulated light while the other, coupled with an electret microphone, is used for sensing the temperature fluctuations transmitted through the gas layer. The thermal diffusivity of CO2-air mixtures as a function of the relative concentration is measured. It is demonstrated that different concentrations of CO2 in air can be detected with precision using the described experimental device.

Surface acoustic wave gas sensor of the sorption type sensitive to the thermal properties of gases

The basic principles of a new surface acoustic wave (SAW) gas sensor are described. Being essentially a sensor of the sorption type, the proposed device possesses certain features of the thermometric SAW sensors and is not only sensitive to the vapors of volatile substances, but capable of detecting gases by their thermal properties as well. In contrast to the known thermometric SAW sensors, the proposed sensor is characterized by high temperature stability and fast response. A variant of the sensor based on a LiNbO3 SAW delay line is described and some results of the test for detecting propane-butane mixtures are presented.

A combined unsteady method for the determination of thermal conductivity of gases and fluids

The unsteady methods of line heat sources and heat impulse are combined to form a convenient mathematical model for the determination of thermal properties of gases and fluids in a hot-wire cell. By taking measurements in the first regular regime, the right-hand side of the system of heat equations to be solved simplifies considerably. Results of numerical simulations are listed.

Heat transfer in a fluidized bed. Part II. Interpretation of the heat transfer coefficient on the basis of solids movement

In Part I the influence of the thermal driving force on the coefficient for heat exchange with a fluidized bed was described. The extent of this was clearly related to the kind of powder fluidized, i.e. powders which exhibited dense phase expansion were strongly influenced as opposed to those which did not exhibit dense phase expansion. The latter yielded heat transfer coefficients which could be reasonably predicted by a theoretical model based on a combination of solids movement and unsteady-state heat conduction, using well-known models from the literature. The slight influence of the driving force on the experimentally determined heat transfer coefficients could also be anticipated when accounting for the temperature-dependent thermal properties of gas and solids. For powders exhibiting dense phase expansion, prediction with the proposed model proved to be impossible. Here, the solids behaviour seems to be governed by random movements which are difficult to relate to fluidizing parameters. Tentative calculations suggested that the bubble frequency may be a useful correlating parameter.

An instrument for the measurement of thermal properties of gases and metal wires

A column instrument developed as a potential device for the accurate measurement of several thermal properties such as the electrical resistivity and hemispherical total emittance of metal wires and the thermal conductivity of gases over an extended temperature range is described. The results are reported for platinum and neon covering the maximum temperature range of 273-1650K. In each case the results of the present work are found to be in good agreement with the available data in the literature. This is regarded as a conclusive evidence in favour of the column apparatus as a multiproperty measuring instrument.

Thermal Properties of Interstellar Gas Heated by Cosmic Rays

view Abstract Citations (115) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Thermal Properties of Interstellar Gas Heated by Cosmic Rays Goldsmith, D. W. ; Habing, H. J. ; Field, G. B. Abstract We present detailed calculations of thermal properties of predominantly neutral interstellar gas heated by low-energy cosmic rays. The heating rate does not depend on the form of the energy spectrum of the cosmic rays, but only on an integral over the spectrum. This integral is proportional to the ioniza~ tion rate ~-. it is shown that two beating processes are important: (i) heating of the free electrons of the gas by direct interaction ~ ith cosmic ra~ s anu i ~ he4tlr~ cau ed }~ elect or 1ibera~'~d b~ osrrnc ra~ particles, which electrons transfer part of their energy to the free electrons of the gas. ii the electron density is low (less than 0.02 na), the second process dominates; otherwise both processes must be con- sidered. Calculations of thermal equilibrium show that the kinetic pressure in the gas has a maximum at an atomic density of about 0.2 cm3. This leads to a model in which the interstellar gas is represented by two thermally stable phases in pressure equilibrium-a rarefied one at about 1()~ ° K and a dense one at about 1000 K. Finally, we discuss the influence on equilibrium temperatures of lowering abundances by accretion of trace elements on grains. Evidence is presented for underabundance of all trace eIemen~s observed in the interstellar gas Publication: The Astrophysical Journal Pub Date: October 1969 DOI: 10.1086/150181 Bibcode: 1969ApJ...158..173G full text sources ADS |

Controlled Recovery of Nonliving Satellites

1 Humble, L. W., Lowdermilk, W. H. and, Desmon, L. G., Measure* ments of Average and Friction Coefficients for Subsonic Flow of Air in Smooth Tubes at High Surface and Fluid Temperatures, NACA Rep. 1020, 1951. (Supersedes NACA RM's E7L31, E8L03, E50E23 and E50H23.) 2 Durham, F. P., Neal, R. C. and Newman, H. J., ''High Temperature Heat Transfer to a Gas Flowing in Heat Generating Tubes with High Heat Flux, presented at Reactor Heat Transfer Conf., Nov. 1957, TID7529, pt. 1, book 2, pp. 502-514. 3 Woolley, H. W., Helium, Table 6.10 of the NBS-NACA Tables of Thermal Properties of Nat. Bur. Standards, 1950. 4 Nuttall, R. L., Helium, Table 6.39 of the NBS-NACA Tables of Thermal Properties of Nat. Bur. Standards, 1950. 5 Nuttall, R. L., Helium, Table 6.42 of the NBS-NACA Tables of Thermal Properties of Gases, Nat. Bur. Standards, 1950. 6 Bernardo, E. and Eian, C. S., Heat-Transfer Tests of Aqueous Ethylene Glycol Solutions in an Electrically Heated Tube, NACA ARR E5F07, 1945. 7 Weiland, W. F. and Lowdermilk, W. H., Measurements of HeatTransfer and Friction Coefficients for Air Flowing in a Tube of LengtbDiameter Ratio of 15 at High Surface Temperatures, NACA RM E53E04, 1953.

Tables of Thermal Properties of Gases

not Available.

Compilation of Thermal Properties of Wind-Tunnel and Jet-Engine Gases at the National Bureau of Standards

Abstract A project for the preparation of a series of tables of thermal properties of gases is described. This project was undertaken by the National Bureau of Standards at the suggestion and with the co-operation of the National Advisory Committee for Aeronautics. The scope of the project, tables now available, work in progress, and plans for the future are described. The lack of adequate data at high temperatures and also at high pressures is pointed out.

Closure to “Discussions of ‘Compilation of Thermal Properties of Wind-Tunnel and Jet-Engine Gases at the National Bureau of Standards’” (1950, Trans. ASME, 72, pp. 782–783)

Closure to “Discussions of ‘Compilation of Thermal Properties of Wind-Tunnel and Jet-Engine Gases at the National Bureau of Standards’” (1950, Trans. ASME, 72, pp. 782–783)

The measurement of the thermal properties of gases and vapours adsorbed on solid surfaces

The measurement of the thermal properties of gases and vapours adsorbed on solid surfaces