Thermal Choking Due to Nonequilibrium Condensation

1994 ◽  
Vol 116 (3) ◽  
pp. 599-604 ◽  
Author(s):  
Abhijit Guha
Keyword(s):  
Gas Dynamics ◽  
Control Volume ◽  
Full Time ◽  
Condensation Zone ◽  
Explicit Equation ◽  
General Validity ◽  
Integral Control ◽  
Classical Gas ◽  
Nonequilibrium Condensation ◽  
Quantity Of Heat

A theory of thermal choking due to nonequilibrium condensation in a nozzle is presented. An explicit equation for the critical quantity of heat in condensing flow has been derived. The equation is of general validity and applies to vapor-droplet flow with or without a carrier gas. It has been usually assumed in the literature that the classical gas dynamics result for the critical quantity of heat applies in condensing flow as well. The classical result is, however, obtained by considering external heat addition to an ideal gas in a constant area duct. In this paper it is shown that the area variation across the condensation zone (although small) and the depletion in the mass of vapor as a result of condensation have profound effects on the critical quantity of heat. The present equation (derived from an integral, control-volume approach) agrees very well with results from full time-marching solution of the nonequilibrium, differential gas dynamic equations. The classical gas dynamics result, on the other hand, seriously underpredicts the critical heat for condensing flow in nozzles (by a factor of three in the example calculation presented).

Solution of One Classical Gas Dynamics Problem

2019 ◽  
Vol 62 (4) ◽  
pp. 612-619
Author(s):  
A. V. Efimov
Keyword(s):  
Gas Dynamics ◽  
Classical Gas

Improvement on Spherical Symmetry in Two-Dimensional Cylindrical Coordinates for a Class of Control Volume Lagrangian Schemes

2012 ◽  
Vol 11 (4) ◽  
pp. 1144-1168 ◽  
Author(s):  
Juan Cheng ◽  
Chi-Wang Shu
Keyword(s):  
Spherical Symmetry ◽  
Gas Dynamics ◽  
Control Volume ◽  
Two Dimensional ◽  
Cylindrical Coordinates ◽  
One Dimensional ◽  
First Order ◽  
Conservation Of Momentum ◽  
Numerical Fluxes ◽  
Geometric Conservation Law

AbstractIn, Maire developed a class of cell-centered Lagrangian schemes for solving Euler equations of compressible gas dynamics in cylindrical coordinates. These schemes use a node-based discretization of the numerical fluxes. The control volume version has several distinguished properties, including the conservation of mass, momentum and total energy and compatibility with the geometric conservation law (GCL). However it also has a limitation in that it cannot preserve spherical symmetry for one-dimensional spherical flow. An alternative is also given to use the first order area-weighted approach which can ensure spherical symmetry, at the price of sacrificing conservation of momentum. In this paper, we apply the methodology proposed in our recent work to the first order control volume scheme of Maire in to obtain the spherical symmetry property. The modified scheme can preserve one-dimensional spherical symmetry in a two-dimensional cylindrical geometry when computed on an equal-angle-zoned initial grid, and meanwhile it maintains its original good properties such as conservation and GCL. Several two-dimensional numerical examples in cylindrical coordinates are presented to demonstrate the good performance of the scheme in terms of symmetry, non-oscillation and robustness properties.

Energy Balance in Vortex-Induced-Vibration of an Inverted Pendulum

2002 ◽  
Author(s):  
P. Dong ◽  
A. Voorhees ◽  
P. Atsavapranee ◽  
S. Kuchnicki ◽  
H. Benaroya ◽  
...  
Keyword(s):  
Inverted Pendulum ◽  
Energy Transport ◽  
Control Volume ◽  
Experimental Methodology ◽  
Fluid Structure Interactions ◽  
Integral Control ◽  
Image Velocimetry ◽  
Induced Motion ◽  
Modeling Data ◽  
Oscillation Frequencies

High resolution Digital Particle Image Velocimetry has been used to measure terms in the integral fluid energy transport equation. These data have been incorporated into a scientifically rigorous Hamilton’s Principle approach for modeling fluid-structure interactions. The interaction being modeled is the vortex-induced motion of a circular cylinder mounted like an inverted pendulum in a water tunnel. This paper describes the experimental methodology used to acquire key modeling data, i.e. kinetic energy transport and work across the boundaries of an integral control volume. There is also a presentation of a simple analysis showing that competition between vortex shedding and cylinder oscillation frequencies give rise to observed beating phenomena.

Another Set of Axioms for Classical Gas Dynamics

1972 ◽  
Vol 13 (6) ◽  
pp. 813-821 ◽  
Author(s):  
Michael Schilder
Keyword(s):  
Gas Dynamics ◽  
Classical Gas

Development of an Aero-Thermodynamics Course to Aid an Undergraduate Propulsion Track

2005 ◽  
Author(s):  
Keith M. Boyer ◽  
Kurt P. Rouser ◽  
Timothy J. Lawrence
Keyword(s):  
Gas Dynamics ◽  
United States Air Force ◽  
Control Volume ◽  
Three Dimensional ◽  
The United States ◽  
Performance Criteria ◽  
Initial Assessment ◽  
Air Force Academy ◽  
Practical Applications ◽  
Hands On

This paper describes the development and assessment of a sophomore-level, aero-thermodynamics class structured to meet the needs of both the Department of Aeronautics and Department of Astronautics at the United States Air Force Academy. The course was developed following ABET EC2000 guidelines. Because of the large core class requirement placed on students at the USAF Academy, this single course was developed as an alternative to students taking traditional separate thermodynamics and gas dynamics courses. Benefits and tradeoffs of this approach are presented. The general philosophy in developing the course was to provide solid foundations in thermodynamics and compressible gas dynamics while motivating and inspiring students to their chosen engineering profession. To that end, the course is loaded with practical applications and hands-on laboratories. Engineering rigor was maintained by inclusion of an unsteady, three-dimensional control volume formulation of the governing equations, emphasizing assumptions and their implications, and enforcing engineering analysis methods. Quantitative assessment of specific performance criteria demonstrates achievement of educational outcomes. Student course critique scores provided additional quantitative data. Finally, an initial assessment of course impact on two different undergraduate propulsion classes demonstrates the intended result — improved understanding of fundamentals allowing for expanded coverage in other areas. In short, the propulsion tracks in both departments appear to be improved.

Non-classical gas dynamics of vapour mixtures

2014 ◽  
Vol 741 ◽  
pp. 681-701 ◽  
Author(s):  
Alberto Guardone ◽  
Piero Colonna ◽  
Emiliano Casati ◽  
Enrico Rinaldi
Keyword(s):  
Binary Mixtures ◽  
Gas Dynamics ◽  
Vapour Phase ◽  
Mixture Composition ◽  
Nonlinearity Parameter ◽  
Mixture Flow ◽  
Cubic Equation ◽  
Ideal Mixing ◽  
Monotone Dependence ◽  
Classical Gas

AbstractThe non-classical gas dynamics of binary mixtures of organic fluids in the vapour phase is investigated for the first time. A predictive thermodynamic model is used to compute the relevant mixture properties, including its critical point coordinates and the local value of the fundamental derivative of gas dynamics $\Gamma $. The considered model is the improved Peng–Robinson Stryjek–Vera cubic equation of state, complemented by the Wong–Sandler mixing rules. A finite thermodynamic region is found where the nonlinearity parameter $\Gamma $ is negative and therefore non-classical gas dynamics phenomena are admissible. A non-monotone dependence of $\Gamma $ on the mixture composition is observed in the case of binary mixtures of siloxane and perfluorocarbon fluids, with the minimum value of $\Gamma $ in the mixture being always larger than that of its more complex component. The observed dependence indicates that non-ideal mixing has a strong influence on the gas dynamics behaviour, either classical or non-classical, of the mixture. Numerical experiments of the supersonic expansion of a mixture flow around a sharp corner show the transition from the classical configuration, exhibiting an isentropic rarefaction fan centred at the expansion corner, to non-classical ones, including mixed expansion waves and rarefaction shock waves, if the mixture composition is changed.

Supernovae and interstellar gas dynamics

1967 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
F. D. Kahn ◽  
L. Woltjer
Keyword(s):  
Lower Limit ◽  
High Velocity ◽  
Gas Dynamics ◽  
Interstellar Cloud ◽  
Interstellar Gas ◽  
Random Motions ◽  
Relativistic Particles

The efficiency of the transfer of energy from supernovae into interstellar cloud motions is investigated. A lower limit of about 0·002 is obtained, but values near 0·01 are more likely. Taking all uncertainties in the theory and observations into account, the energy per supernova, in the form of relativistic particles or high-velocity matter, needed to maintain the random motions in the interstellar gas is estimated as 1051·4±1ergs.

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