Computerized Analysis of Dynamic Pressure Exchanger Scavenge Processes

1975 ◽  
Vol 189 (1) ◽  
pp. 149-158 ◽  
Author(s):  
P. H. Azoury ◽  
S. M. Hai
Keyword(s):  
Differential Equations ◽  
Specific Heat ◽  
High Performance ◽  
Gas Flow ◽  
Previous Analysis ◽  
Dynamic Pressure ◽  
Ideal Gas ◽  
Wave Processes ◽  
One Dimensional ◽  
Good Agreement

The present work supplements a previous analysis by Azoury of the basic wave processes in a d.p.e. (dynamic pressure exchanger) cell. A hybrid computerized method of integrating the differential equations of unsteady one-dimensional ideal gas flow is used to analyse the component scavenge processes of the d.p.e. in a looped arrangement. These processes are employed to investigate the effect of the relative nature of the interacting gases on d.p.e. performance. A criterion of high performance is proposed in terms of the overall strength of the interface between the gases and their relative specific heat ratios. The criterion gives good agreement with theory when tested with experimental results obtained on two d.p.e. test units.

Optimization of synthetic jet actuation by analytical modeling

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Max Huber ◽  
Andreas Zienert ◽  
Perez Weigel ◽  
Martin Schüller ◽  
Hans-Reinhard Berger ◽  
...  
Keyword(s):  
High Performance ◽  
Synthetic Jet ◽  
Parameter Study ◽  
Content Type ◽  
One Dimensional ◽  
Wide Range ◽  
Jet Actuators ◽  
Different Dimensions ◽  
Oscillation Correction ◽  
Good Agreement

Purpose The purpose of this paper is to analyze and optimize synthetic jet actuators (SJAs) by means of a literature-known one-dimensional analytical model. Design/methodology/approach The model was fit to a wide range of experimental data from in-house built SJAs with different dimensions. A comprehensive parameter study was performed to identify coupling between parameters of the model and to find optimal dimensions of SJAs. Findings The coupling of two important parameters, the diaphragm resonance frequency and the cavity volume, can be described by a power law. Optimal orifice length and diameter can be calculated from cavity height in good agreement with literature. A transient oscillation correction is required to get correct simulation outcomes. Originality/value Based on these findings, SJA devices can be optimized for maximum jet velocity and, therefore, high performance.

Similarity Solutions of Cylindrical Shock Waves in Magnetogasdynamics With Thermal Radiation

2015 ◽  
Vol 11 (3) ◽  
Author(s):  
Rajan Arora ◽  
Ankita Sharma
Keyword(s):  
Differential Equations ◽  
Unsteady Motion ◽  
Similarity Solutions ◽  
Ideal Gas ◽  
Time Dependent ◽  
Radiative Cooling ◽  
Azimuthal Magnetic Field ◽  
Cylindrical Shock Wave ◽  
One Dimensional ◽  
Lie Group Of Transformations

Using Lie group of transformations, here we consider the problem of finding similarity solutions to the system of partial differential equations (PDEs) governing one-dimensional unsteady motion of an ideal gas in the presence of radiative cooling and idealized azimuthal magnetic field. The similarity solutions are investigated behind a cylindrical shock wave which is produced as a result of a sudden explosion or driven out by an expanding piston. The shock is assumed to be strong and propagates into a medium which is at rest, with nonuniform density. The total energy of the wave is assumed to be time dependent obeying a power law. Indeed, with the use of the similarity solution, the problem is transformed into a system of ordinary differential equations (ODEs), which in general is nonlinear; in some cases, it is possible to solve these ODEs to determine some special exact solutions.

scholarly journals Quotients of Euler Equations on Space Curves

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 186
Author(s):  
Anna Duyunova ◽  
Valentin Lychagin ◽  
Sergey Tychkov
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Euler Equations ◽  
Gas Flow ◽  
Euler System ◽  
Partial Differential ◽  
One Dimensional ◽  
Space Curves ◽  
Ode System

Quotients of partial differential equations are discussed. The quotient equation for the Euler system describing a one-dimensional gas flow on a space curve is found. An example of using the quotient to solve the Euler system is given. Using virial expansion of the Planck potential, we reduce the quotient equation to a series of systems of ordinary differential equations (ODEs). Possible solutions of the ODE system are discussed.

scholarly journals Interaction of waves in one-dimensional dusty gas flow

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pooja Gupta ◽  
Rahul Kumar Chaturvedi ◽  
L. P. Singh
Keyword(s):  
Shock Wave ◽  
High Frequency ◽  
Gas Flow ◽  
Ideal Gas ◽  
Transport Equations ◽  
Dust Particles ◽  
Multiple Time Scales ◽  
Dusty Gas ◽  
One Dimensional ◽  
Geometrical Acoustics

AbstractThe present study uses the theory of weakly nonlinear geometrical acoustics to derive the high-frequency small amplitude asymptotic solution of the one-dimensional quasilinear hyperbolic system of partial differential equations characterizing compressible, unsteady flow with generalized geometry in ideal gas flow with dust particles. The method of multiple time scales is applied to derive the transport equations for the amplitude of resonantly interacting high-frequency waves in a dusty gas. These transport equations are used for the qualitative analysis of nonlinear wave interaction process and self-interaction of nonlinear waves which exist in the system under study. Further, the evolutionary behavior of weak shock waves propagating in ideal gas flow with dust particles is examined here. The progressive wave nature of nonresonant waves terminating into the shock wave and its location is also studied. Further, we analyze the effect of the small solid particles on the propagation of shock wave.

Transients During a Railway Air Brake Release Demand

1990 ◽  
Vol 204 (1) ◽  
pp. 31-38 ◽  
Author(s):  
M A Murtaza ◽  
S B L Garg
Keyword(s):  
Partial Differential Equations ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Differential Equations ◽  
Difference Method ◽  
Laboratory Data ◽  
One Dimensional ◽  
The Finite Difference Method ◽  
Air Brake System ◽  
Good Agreement

This paper deals with the simulation of railway air brake release demand of a twin-pipe graduated release railway air brake system based on the solution of partial differential equations governing one-dimensional flow by the finite difference method supported by extrapolation/interpolation. Air brake release demand is simulated as an exponential input of pressure. The analysis incorporates the corrections needed to be used for various restrictions in the brake pipeline. Results are in good agreement with the laboratory data.

Simulations of Reacting Fluidized Beds Using an Agent-Based Bubble Model

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
S. Pannala ◽  
C.Stuart Daw ◽  
John Halow
Keyword(s):  
Gas Flow ◽  
Bubble Dynamics ◽  
Dynamic Pressure ◽  
Emergent Behavior ◽  
Ozone Decomposition ◽  
Agent Based ◽  
Dynamic Pressure Measurements ◽  
Bubbling Beds ◽  
The Impact ◽  
Good Agreement

We apply a low-order dynamical model for simulating the conversion of bubbling bed reactors. The model includes mass-transfer and first-order reactions between the gas and solids and accounts for upward motion and interactions between bubbles. On a time-average basis, we get reasonably good agreement between the model and experimental measurements from an ozone decomposition reactor. The collective result of the bubble dynamics is a type of global emergent behavior characterized by the formation of a pulsing central channel of high void fraction and high gas flow. These pulsations appear to be similar in character to those typically seen in dynamic pressure measurements of bubbling beds. We use our model to explore the impact of these pulsations on reactor conversion.

scholarly journals One-Dimensional Optimal System for 2D Rotating Ideal Gas

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1115 ◽  
Author(s):  
Andronikos Paliathanasis
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Ideal Gas ◽  
Optimal System ◽  
Lie Point Symmetries ◽  
Rotating System ◽  
Partial Differential ◽  
One Dimensional ◽  
Rotating Systems ◽  
The One

We derive the one-dimensional optimal system for a system of three partial differential equations, which describe the two-dimensional rotating ideal gas with polytropic parameter γ > 2 . The Lie symmetries and the one-dimensional optimal system are determined for the nonrotating and rotating systems. We compare the results, and we find that when there is no Coriolis force, the system admits eight Lie point symmetries, while the rotating system admits seven Lie point symmetries. Consequently, the two systems are not algebraic equivalent as in the case of γ = 2 , which was found by previous studies. For the one-dimensional optimal system, we determine all the Lie invariants, while we demonstrate our results by reducing the system of partial differential equations into a system of first-order ordinary differential equations, which can be solved by quadratures.

The theory of one-dimensional adiabatic ideal-gas flow

1972 ◽  
Vol 4 (3) ◽  
pp. 93-94
Author(s):  
M. D. Ustinov
Keyword(s):  
Gas Flow ◽  
Ideal Gas ◽  
One Dimensional

scholarly journals Selected Mathematical Models Describing Flow in Gas Pipelines

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 478
Author(s):  
Andrzej J. Osiadacz ◽  
Marta Gburzyńska
Keyword(s):  
Differential Equations ◽  
High Speed ◽  
Gas Flow ◽  
Complex Structure ◽  
Hyperbolic Model ◽  
Gas Flows ◽  
Gas Pipelines ◽  
One Dimensional ◽  
Network Operation ◽  
The Mathematical Model

The main aim of simulation programs is to study the behavior of gas pipe networks in certain conditions. Solving a specified set of differential equations describing transient (unsteady) flow in a gas pipeline for the adopted parameters of load and supply will help us find out the value of pressure or flow rate at selected points or along selected sections of the network. Transient gas flow may be described by a set of simple or partial differential equations classified as hyperbolic or parabolic. Derivation of the mathematical model of transient gas flow involves certain simplifications, of which one-dimensional flow is most important. It is very important to determine the conditions of pipeline/transmission network operation in which the hyperbolic model and the parabolic model, respectively, should be used. Parabolic models can be solved numerically in a much simpler way and can be used to design simulation programs which allow us to calculate the network of any structure and any number of non-pipe elements. In some conditions, however, they describe the changes occurring in the network less accurately than hyperbolic models do. The need for analysis, control, and optimization of gas flows in high-pressure gas pipelines with complex structure increases significantly. Very often, the time allowed for analysis and making operational decisions is limited. Therefore, efficient models of unsteady gas flows and high-speed algorithms are essential.

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