A numerical method of computing interior subsonic ideal gas flows with a twist

This paper describes and validates a numerical method for the calculation of unsteady inviscid and viscous flows. A companion paper compares experimental measurements of unsteady heat transfer on a transonic rotor with the corresponding computational results. The mathematical model is the Reynolds-averaged unsteady Navier–Stokes equations for a compressible ideal gas. Quasi-three-dimensionality is included through the use of a variable streamtube thickness. The numerical algorithm is unusual in two respects: (a) For reasons of efficiency and flexibility, it uses a hybrid Navier–Stokes/Euler method, and (b) to allow for the computation of stator/rotor combinations with arbitrary pitch ratio, a novel space–time coordinate transformation is used. Several test cases are presented to validate the performance of the computer program, UNSFLO. These include: (a) unsteady, inviscid flat plate cascade flows (b) steady and unsteady, viscous flat plate cascade flows, (c) steady turbine heat transfer and loss prediction. In the first two sets of cases comparisons are made with theory, and in the third the comparison is with experimental data.

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Numerical Method for Simulating High Pressure CO2 Flows With Nonequilibrium Condensation

Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2018-75592 ◽

2018 ◽

Author(s):

Takashi Furusawa ◽

Hironori Miyazawa ◽

Shota Moriguchi ◽

Satoru Yamamoto

Keyword(s):

High Pressure ◽

Numerical Method ◽

Supercritical Co2 ◽

Compressible Flows ◽

Ideal Gas ◽

Experimental Result ◽

High Mass ◽

Real Gas ◽

High Pressure Co2 ◽

Nonequilibrium Condensation

A numerical method for compressible flows with nonequilibrium condensation is reconstructed for simulating supercritical CO2 flows with nonequilibrium condensation under high pressure conditions. Thermophysical properties are interpolated from pressure-temperature look-up tables and density-internal energy look-up tables, which are generated using the polynomial equations in REFPROP. We employ the high pressure nonequilibrium condensation model in which the critical radius of a liquid droplet is modified by considering non-ideal gas. We simulate high pressure CO2 flows through a Laval nozzle, which was experimentally investigated by Lettieri et al. High-pressure CO2 passes through the nozzle, leading to a decrease in its pressure and temperature. It reaches the supercooled condition near the throat. Nucleation and the subsequent growth of droplets lead to an increase in the condensate mass fraction in the diverging area. The proposed method for real gas reproduced the peak of pressure distribution owing to the release of latent heat, whereas the numerical result assuming ideal gas is different from the experimental result. The nucleation region obtained using the present method is earlier and narrower than that in the case of ideal gas. The early and rapid nucleation leads to the high mass condensate rate at the outlet. These results show that considering the real gas effect and nonequilibrium condensation is crucial for developing the impeller of a compressor for the supercritical CO2 Brayton cycle.

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An Enskog based Monte Carlo method for high Knudsen number non-ideal gas flows

Computers & Fluids ◽

10.1016/j.compfluid.2006.12.006 ◽

2007 ◽

Vol 36 (8) ◽

pp. 1291-1297 ◽

Cited By ~ 28

Author(s):

Moran Wang ◽

Zhixin Li

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Knudsen Number ◽

Ideal Gas ◽

Gas Flows

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Examples of transonic ideal gas flows with a shock

Fluid Dynamics ◽

10.1007/bf01032382 ◽

1972 ◽

Vol 4 (1) ◽

pp. 31-33

Author(s):

G. D. Sevost'yanov

Keyword(s):

Ideal Gas ◽

Gas Flows

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Time-Dependent Pipe Forces Caused by Blowdown and Flow Stoppage

Journal of Fluids Engineering ◽

10.1115/1.3447046 ◽

1973 ◽

Vol 95 (3) ◽

pp. 422-428 ◽

Cited By ~ 4

Author(s):

F. J. Moody

Keyword(s):

Ideal Gas ◽

Piping System ◽

Gas Flows ◽

Time Behavior ◽

Pipe System ◽

Economical Design ◽

Graphical Summary ◽

Reaction Forces ◽

Force Time ◽

System Layout

Formulations are developed in this study for rapid estimates of time-and-space-dependent pipe reaction forces caused by either sudden blowdown or flow stoppage in a fluid piping system. The analytical model is a uniform pipe with arbitrary bends and friction, a pressure source at one end, and a sudden opening or closing value at the other end. A homogeneous mixture of liquid and ideal gas flows in the system. The method of characteristics is used to obtain fluid-mechanical properties, which then are employed to predict associated pipe loads. A graphical summary of results includes initial and steady blowdown forces, wave propagation forces, and local force-time behavior. The formulations presented are expected to provide a basis for confident, efficient, and economical design of pipe system layout and motion restraints.

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A numerical method for calculating gas flows in channels and nozzles in the direct, inverse and combined formulations

USSR Computational Mathematics and Mathematical Physics ◽

10.1016/0041-5553(87)90066-8 ◽

1987 ◽

Vol 27 (5) ◽

pp. 190-196

Author(s):

I.L. Osipov ◽

A.V. Shipilin ◽

N.P. Shulishnina

Keyword(s):

Numerical Method ◽

Gas Flows

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Validation of a Numerical Method for Unsteady Flow Calculations

Volume 1: Turbomachinery ◽

10.1115/91-gt-271 ◽

1991 ◽

Cited By ~ 8

Author(s):

Michael Giles ◽

Robert Haimes

Keyword(s):

Heat Transfer ◽

Flat Plate ◽

Numerical Method ◽

Stokes Equations ◽

Companion Paper ◽

Ideal Gas ◽

Euler Method ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Loss Prediction

This paper describes and validates a numerical method for the calculation of unsteady inviscid and viscous flows. A companion paper compares experimental measurements of unsteady heat transfer on a transonic rotor with the corresponding computational results. The mathematical model is the Reynolds-averaged unsteady Navier-Stokes equations for a compressible ideal gas. Quasi-three-dimensionality is included through the use of a variable streamtube thickness. The numerical algorithm is unusual in two respects: a) for reasons of efficiency and flexibility it uses a hybrid Navier-Stokes/Euler method, and b) to allow for the computation of stator/rotor combinations with arbitrary pitch ratio a novel space-time coordinate transformation is used. Several test cases are presented to validate the performance of the computer program, UNSFLO. These include: a) unsteady, inviscid flat plate cascade flows, b) steady and unsteady, viscous flat plate cascade flows, c) steady turbine heat transfer and loss prediction. In the first two sets of cases comparisons are made with theory, and in the third the comparison is with experimental data.

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