Sizing Safety Valve Vent Pipes for Saturated Steam

1982 ◽  
Vol 104 (1) ◽  
pp. 247-251
Author(s):  
H. E. Brandmaier
Keyword(s):  
Ideal Gas ◽  
Gas Analysis ◽  
Saturated Steam ◽  
Flow Conditions ◽  
Flow Properties ◽  
Pipe Length ◽  
One Dimensional ◽  
Choked Flow ◽  
Pipe Outlet ◽  
Orifice Valve

An earlier one-dimensional ideal gas analysis was changed to incorporate equilibrium properties of steam as given by the 1967 ASME steam tables. A generalized procedure based on pressure and entropy as independent variables is used to calculate choked flow conditions at the valve orifice, valve pipe outlet and vent pipe outlet. At the third location, the results are independent of whether flow in the vent pipe is supersonic or subsonic. An integral method is used to calculate the vent pipe length required to choke the flow. Computed data are compared with ideal gas data. The vent pipe size, to prevent blowback into the powerplant, is less conservative using real steam data. The flow properties, particularly specific volume, are significantly different.

Mathematical Analysis for Off-Design Performance of Cryogenic Turboexpander

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Subrata K. Ghosh ◽  
R. K. Sahoo ◽  
Sunil K. Sarangi
Keyword(s):  
Pressure Ratio ◽  
Expansion Ratio ◽  
Flow Conditions ◽  
Flow Properties ◽  
Dimensional Solution ◽  
One Dimensional ◽  
Design Performance ◽  
Fluid Properties ◽  
The Mean ◽  
Inlet Conditions

A study has been conducted to determine the off-design performance of cryogenic turboexpander. A theoretical model to predict the losses in the components of the turboexpander along the fluid flow path has been developed. The model uses a one-dimensional solution of flow conditions through the turbine along the mean streamline. In this analysis, the changes of fluid and flow properties between different components of turboexpander have been considered. Overall, turbine geometry, pressure ratio, and mass flow rate are input information. The output includes performance and velocity diagram parameters for any number of given speeds over a range of turbine pressure ratio. The procedure allows any arbitrary combination of fluid species, inlet conditions, and expansion ratio since the fluid properties are properly taken care of in the relevant equations. The computational process is illustrated with an example.

Subsonic Elector Nozzle Limiting Flow Conditions

2003 ◽  
Vol 125 (3) ◽  
pp. 851-854 ◽  
Author(s):  
L. J. De Chant
Keyword(s):  
Design Space ◽  
Reverse Flow ◽  
Control Volume ◽  
Flow Conditions ◽  
Efficient Tool ◽  
One Dimensional ◽  
Choked Flow ◽  
Ejector Nozzle ◽  
Classical Control ◽  
Good Agreement

This paper describes an analytical method used to provide information concerning limiting flows for subsonic ejector nozzles. Three potential limiting flows have been identified and modeled using reduced control volume based analysis: (1) incipient reverse flow into the secondary inlet, (2) choked flow in the secondary inlet, and (3) choked flow in the exit mixing stream. Comparison of the methods developed here with the classical control volume portion of an ejector nozzle code have been performed and show good agreement. As such, it is concluded, that within the scope of one-dimensional control-volume based computations, that the methods developed here provide an efficient tool to help delimit the design space acceptable for ejector operation.

Averaging Methods for Determining the Performance of Large Fans from Field Measurements

1981 ◽  
Vol 103 (2) ◽  
pp. 345-347 ◽  
Author(s):  
P. M. Gerhart
Keyword(s):  
Pressure Rise ◽  
Field Measurements ◽  
Ideal Gas ◽  
Correction Factors ◽  
Flow Properties ◽  
State Equations ◽  
One Dimensional ◽  
Performance Variables ◽  
Definition Of ◽  
Velocity Pressure

When testing large fans in the field, it is often necessary to make measurements at locations where the distributions of gas velocity, pressure, and temperature are highly irregular. When this occurs the fan pressure rise or fan specific energy is usually expressed in terms of average values of pressure, density, and temperature. This paper proposes criteria for the definition of such averages and develops defining equations for them. The averages proposed allow the continuity, energy, and ideal gas state equations to be written in simple one-dimensional form without correction factors. Performance variables such as total pressure are defined in the customary way from the averages of the fundamental flow properties.

Choking and Mixing of Two Compressible Fluid Streams

1976 ◽  
Vol 98 (2) ◽  
pp. 311-317 ◽  
Author(s):  
D. R. Otis
Keyword(s):  
Compressible Fluid ◽  
Ideal Gas ◽  
Gas Analysis ◽  
Mixing Process ◽  
Mixed States ◽  
Mixed Flow ◽  
One Dimensional ◽  
Process Solution ◽  
Forbidden Region ◽  
The Relationship

The mixing of a supersonic with a subsonic stream is treated in a one-dimensional, ideal gas analysis to determine when the mixed flow can be supersonic and to reveal the relationship between certain phenomena described by the terms “forbidden region” of “thermal choking.” A singularity in the equations is shown to divide the mixing process solution curves into two branches: subcritical or supercritical leading, respectively, to subsonic or supersonic mixed states.

Subsonic Adiabatic Flow in a Duct of Constant Cross-Sectional Area

1964 ◽  
Vol 68 (638) ◽  
pp. 117-126 ◽  
Author(s):  
A. J. Ward Smith
Keyword(s):  
Flow Theory ◽  
Flow Conditions ◽  
Mean Flow ◽  
Flow Properties ◽  
Cross Sectional ◽  
Fully Developed Flow ◽  
One Dimensional ◽  
Dimensional Flow ◽  
Loss Coefficients ◽  
The One

SummaryStarting from the momentum integral equation an analysis is made of fully-developed flow in a straight pipe. This analysis shows the assumptions implicit in the one-dimensional theory of adiabatic constant-area flow with friction. For conditions of practical interest the approximations associated with the use of the one-dimensional flow theory are shown to be small.Flow with a developing velocity profile and flow in a bend are then analysed. Introducing approximations revealed in the analysis of fully-developed flow, a simple relation is obtained between the variation of mean flow properties along the duct under incompressible and compressible flow conditions. This relation may be written in the same form as the corresponding relation derived using the one-dimensional flow theory. In a similar manner to one-dimensional flow theory, the relation is readily extended to apply over a series of components of constant cross-sectional area.The results of the analysis are also presented in terms of static and total pressure loss coefficients. This form of presentation demonstrates that there are appreciable effects of Mach number, on the pressure loss coefficients, where they are often assumed to be small.The analysis does not enable the variation of the mean flow properties to be calculated ab initio. Its application is to be found in problems where a knowledge of the performance of a component, or series of components, is required under compressible flow conditions, the performance under incompressible flow conditions already being available from theoretical or experimental data.A comparison of predicted and experimental data for flow in bends and flow in combinations of duct components shows good agreement over much of the subsonic speed regime.

The combined effect of lattice’s uniaxial strains and electron–phonon interaction’s screening on TBEC of the intersite bipolarons

2016 ◽  
Vol 30 (26) ◽  
pp. 1650186
Author(s):  
B. Yavidov ◽  
SH. Djumanov ◽  
T. Saparbaev ◽  
O. Ganiyev ◽  
S. Zholdassova ◽  
...  
Keyword(s):  
Ideal Gas ◽  
Einstein Condensation ◽  
Chain Model ◽  
One Dimensional ◽  
Electron Phonon Interaction ◽  
Model Lattice ◽  
Experimental Values ◽  
Bose Einstein ◽  
Derivatives Of ◽  
The Ideal

Having accepted a more generalized form for density-displacement type electron–phonon interaction (EPI) force we studied the simultaneous effect of uniaxial strains and EPI’s screening on the temperature of Bose–Einstein condensation [Formula: see text] of the ideal gas of intersite bipolarons. [Formula: see text] of the ideal gas of intersite bipolarons is calculated as a function of both strain and screening radius for a one-dimensional chain model of cuprates within the framework of Extended Holstein–Hubbard model. It is shown that the chain model lattice comprises the essential features of cuprates regarding of strain and screening effects on transition temperature [Formula: see text] of superconductivity. The obtained values of strain derivatives of [Formula: see text] [Formula: see text] are in qualitative agreement with the experimental values of [Formula: see text] [Formula: see text] of La[Formula: see text]Sr[Formula: see text]CuO4 under moderate screening regimes.

Diabatic Nozzle Flow with Constant Small Stage Efficiency

1960 ◽  
Vol 64 (598) ◽  
pp. 632-635 ◽  
Author(s):  
R. A. A. Bryant
Keyword(s):  
Gas Flow ◽  
Nozzle Flow ◽  
Flow Conditions ◽  
One Dimensional ◽  
Real Flow ◽  
Stage Efficiency ◽  
Frictional Effects

The concept of small stage efficiency is introduced when studying one-dimensional gas flow in nozzles in order to permit a closer approximation of real flow conditions than is possible from an isentropic analysis. It is more or less conventional to assume the flow conditions are adiabatic whenever the small stage efficiency is used. That is to say, small stage efficiency is generally considered in relation to flows contained within adiabatic boundaries, in which case it becomes a measure of the heat generated by internal frictional effects alone.

A Study of a Sharp 90 Degree Curved Flow

1992 ◽  
Author(s):  
R. H. Kim
Keyword(s):  
Turbulence Model ◽  
Ideal Gas ◽  
Radius Of Curvature ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Algebraic Stress Model ◽  
Finite Difference Technique ◽  
Curved Tube ◽  
Kinetic Energy Loss ◽  
The Ideal

Abstract An investigation of air flow along a 90 degree elbow-like tube is conducted to determine the velocity and temperature distributions of the flow. The tube has a sharp 90 degree turn with a radius of curvature of almost zero. The flow is assumed to be a steady two-dimensional turbulent flow satisfying the ideal gas relation. The flow will be analyzed using a finite difference technique with the K-ε turbulence model, and the algebraic stress model (ASM). The FLUENT code was used to determine the parameter distributions in the passage. There are certain conditions for which the K-ε model does not describe the fluid phenomenon properly. For these conditions, an alternative turbulence model, the ASM with or without QUICK was employed. FLUENT has these models among its features. The results are compared with the result computed by using elementary one-dimensional theory including the kinetic energy loss along the passage of the sharp 90 degree curved tube.

Statistical mechanics of one-dimensional solitary-wave-bearing scalar fields: Exact results and ideal-gas phenomenology

1980 ◽  
Vol 22 (2) ◽  
pp. 477-496 ◽  
Author(s):  
J. F. Currie ◽  
J. A. Krumhansl ◽  
A. R. Bishop ◽  
S. E. Trullinger
Keyword(s):  
Solitary Wave ◽  
Statistical Mechanics ◽  
Scalar Fields ◽  
Ideal Gas ◽  
Exact Results ◽  
One Dimensional

The Structure of Laminar Premixed H2-Air Flames at Elevated Pressures

2000 ◽  
Vol 214 (4) ◽  
Author(s):  
M. El-Gamal ◽  
E. Gutheil ◽  
J. Warnatz
Keyword(s):  
Laminar Flame ◽  
Flame Structure ◽  
Ideal Gas ◽  
Fortran Program ◽  
Laminar Flame Speed ◽  
Real Gas ◽  
One Dimensional ◽  
Rocket Propulsion ◽  
Elevated Pressures ◽  
Engine Combustion

In high-pressure flames that occur in many practical combustion devices such as industrial furnaces, rocket propulsion and internal engine combustion, the assumption of an ideal gas is not appropriate. The present paper presents a model that includes modifications of the equation of state, transport and thermodynamic properties. The model is implemented into a Fortran program that was developed to simulate numerically one-dimensional planar premixed flames. The influence of the modifications for the real gas behavior on the laminar flame speed and on flame structure is illustrated for stoichiometric H

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