Nonideal Isentropic Gas Flow Through Converging-Diverging Nozzles

1990 ◽  
Vol 112 (4) ◽  
pp. 455-460 ◽  
Author(s):  
W. Bober ◽  
W. L. Chow
Keyword(s):  
Mach Number ◽  
Gas Flow ◽  
Accurate Solution ◽  
Gas Flows ◽  
Kutta Method ◽  
Runge Kutta Method ◽  
Nonideal Gas ◽  
Reservoir Conditions ◽  
Flow Through ◽  
Isentropic Gas

A method for treating nonideal gas flows through converging-diverging nozzles is described. The method incorporates the Redlich-Kwong equation of state. The Runge-Kutta method is used to obtain a solution. Numerical results were obtained for methane gas. Typical plots of pressure, temperature, and area ratios as functions of Mach number are given. From the plots, it can be seen that there exists a range of reservoir conditions that require the gas to be treated as nonideal if an accurate solution is to be obtained.

Experiments on the Resistance Law for Non-Darcy Compressible Gas Flows in Porous Media

1974 ◽  
Vol 96 (4) ◽  
pp. 353-357 ◽  
Author(s):  
B. A. Masha ◽  
G. S. Beavers ◽  
E. M. Sparrow
Keyword(s):  
Reynolds Number ◽  
Porous Material ◽  
Incompressible Flow ◽  
Gas Flow ◽  
Strong Support ◽  
Reynolds Numbers ◽  
Gas Flows ◽  
Pressure Distributions ◽  
Flow Through ◽  
Compressible Gas

Experiments were performed to examine the resistance law for non-Darcy compressible gas flow through a porous material. A particular objective of the investigation was to determine whether a resistance law deduced from incompressible flow experiments could be applied to flows with significant density changes. To this end, the coefficients appearing in the Forchheimer resistance law were first determined from experiments in the incompressible flow regime. These values were then used in an analytical model employing the Forchheimer resistance law to predict streamwise pressure distributions for subsonic compressible flow through the porous material. Corresponding experimental pressure distributions were measured for flow Reynolds numbers up to 81.6. At the highest Reynolds number of the tests the density changed by about a factor of two along the length of the porous medium. The greatest discrepancy between experimental and predicted pressures at any Reynolds number was 2 percent. This agreement lends strong support to the validity of using the incompressible Forchheimer resistance law for subsonic flows in which density changes are significant.

Structure and Pressure Drop in Particle-Laden Gas Flow Through a Pipe Bend: A Numerical Analysis by the Euler/Lagrange Approach

2009 ◽  
Author(s):  
S. Lai´n ◽  
M. Sommerfeld
Keyword(s):  
Pressure Drop ◽  
Gas Flow ◽  
Gas Flows ◽  
Wall Roughness ◽  
Mass Loading ◽  
Particle Collisions ◽  
Pipe Bend ◽  
Flow Through ◽  
Fully Coupled ◽  
Lagrange Approach

The structure of particle-laden gas flows in a horizontal-to-vertical elbow is investigated numerically for analysing the required modelling depth. The numerical computations are performed with the fully coupled Euler-Lagrange approach considering all the relevant forces: drag, gravity-buoyancy and lift forces (slip-shear and slip-rotational). Moreover, interparticle and particle-rough wall collisions are taken into account by means of stochastic approaches. The effect of the different mechanisms, i.e. wall roughness, inter-particle collisions and mass loading, on the flow structure in the bend and the resulting pressure drop are investigated.

Theoretic Analysis of Middle Ear Gas Composition under Conditions of Nonphysiologic Ventilation

1992 ◽  
Vol 101 (5) ◽  
pp. 445-451 ◽  
Author(s):  
Ervin J. Ostfeld ◽  
Alexander Silberberg
Keyword(s):  
Steady State ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Gas Flow ◽  
High Rate ◽  
Gas Flows ◽  
Gas Composition ◽  
Flow Through ◽  
Pressure Changes ◽  
Patulous Eustachian Tube

As gas flows in and out of the nasopharynx, the pressure in that region fluctuates. It drops below or rises above atmospheric pressure, which is itself not constant but is subject to changes in altitude and weather. Such pressure changes in the nasopharynx produce a pumping of gas into and out of the middle ear. The net amount of middle ear gas transferred from or to the nasopharynx will, component for component, in steady state exactly equal the amount of middle ear gas transferred to or from the microcirculation by means of diffusional absorption by (or release from) the mucosa. In the case of a permanently patulous eustachian tube, a single parameter, characteristic of the rate of ventilation through the open eustachian tube, is found to determine the gas composition in the middle ear, whereas in the case of a middle ear ventilated by tympanostomy, two rate-of-ventilation parameters, one for gas flow through the ventilation tube and one for flow through a periodically open eustachian tube, determine the steady state gas composition. A high rate of ventilation favors absorption of oxygen and venting of carbon dioxide from the middle ear in both cases.

The Influence of Exhaust Poppet Valve Gas Flow on Reciprocating Engine Noise

1975 ◽  
Vol 189 (1) ◽  
pp. 461-469 ◽  
Author(s):  
T. J. Williams ◽  
J. B. Cox
Keyword(s):  
Gas Flow ◽  
Combustion Engine ◽  
Flow Characteristics ◽  
Exhaust System ◽  
Gas Flows ◽  
Frequency Spectra ◽  
Reciprocating Engine ◽  
Flow Through ◽  
Field Noise ◽  
Good Agreement

The far field noise generated by cold air flowing through stationary and reciprocating exhaust poppet valves into a cylindrical duct or pipe has been investigated. A method of predicting the intensity and frequency spectrum of the noise generated in such circumstances in terms of the known or assumed geometry and flow characteristics of the valves is presented. Comparisons of the predicted frequency spectra with measured values show good agreement for steady gas flows through stationary valves and for unsteady flow through a simplified exhaust system of a motored single cylinder internal combustion engine.

Heat Transfer Characteristics of Turbulent Gas Flow Through Micro-Tubes

2010 ◽  
Author(s):  
Chungpyo Hong ◽  
Yuki Uchida ◽  
Takaharu Yamamoto ◽  
Yutaka Asako ◽  
Koichi Suzuki
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Wall Temperature ◽  
Transfer Rate ◽  
Gas Flow ◽  
Gas Flows ◽  
Heat Transfer Characteristics ◽  
Total Temperature ◽  
Flow Through ◽  
Turbulent Gas Flow

This paper presents experimental results on heat transfer characteristics of turbulent gas flows though a micro-tube with constant wall temperature. The experiments were performed for nitrogen gas flows through a micro-tube with 242μm in diameter and 50 mm in length. The wall temperature was maintained at 5K, 20K and 30K higher than the inlet temperature by circulating water around the micro-tube, respectively. In order to measure heat transfer rate of gas flow through a micro-tube, the total temperature at a micro-tube exit was measured. The stagnation pressure was chosen in such a way that the Reynolds number ranges from 3000 to 12000. The outlet pressure was fixed at the atmospheric condition. The total temperature at the outlet, the inlet stagnation temperature, the mass flow rate, and the inlet pressure were measured. The heat transfer rates obtained by the present study are higher than those of the incompressible flow. This is due to the additional heat transfer near the micro-tube outlet caused by the energy conversion into kinetic energy. A correlation for the prediction of the heat transfer rate of the turbulent gas flow through a micro-tube was proposed.

scholarly journals Investigation of Subsonic and Hypersonic Rarefied Gas Flow Over a Backward Facing Step

2019 ◽  
Author(s):  
Deepak Nabapure ◽  
Jayesh Sanwal ◽  
Sreeram Rajesh ◽  
K Ram Chandra Murthy
Keyword(s):  
Mach Number ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Flow Characteristics ◽  
Direct Simulation Monte Carlo ◽  
Primary Objective ◽  
Gas Flows ◽  
Backward Facing Step ◽  
Rarefied Gas Flows ◽  
Velocity Pressure

In the present study the Direct Simulation Monte Carlo (DSMC) method, which is one of most the widely used numerical methods to study the rarefied gas flows, is applied to investigate the flow characteristics of a hypersonic and subsonic flow over a backward-facing step. The work is driven by the interest in exploring the effects of the Mach number on the flow behaviour. The primary objective of this paper is to study the variation of velocity, pressure, and temperature with Mach number. The numerical tool is validated with well-established results from the literature and a good agreement is found among them. The flow is analyzed and some comments on the characteristics of the flow are also added.

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