Expansion of a Very Low Quality Two-Phase Fluid Through a Convergent-Divergent Nozzle

1964 ◽  
Vol 86 (2) ◽  
pp. 247-254 ◽  
Author(s):  
E. S. Starkman ◽  
V. E. Schrock ◽  
K. F. Neusen ◽  
D. J. Maneely
Keyword(s):  
Experimental Data ◽  
Slip Flow ◽  
Design Criteria ◽  
Saturated Liquid ◽  
Two Phase ◽  
Flow Rates ◽  
Isentropic Expansion ◽  
Mass Flow Rates ◽  
Laval Nozzles ◽  
Phase Fluid

Flow in de Laval nozzles of high pressure, low-quality steam-water mixtures was investigated to determine the resulting mass flow rates and to acquire design criteria information. Qualities ranged from 0 to 20 percent and pressures up to 1000 psia. Comparisons of the experimental data to three simple models: (a) isentropic expansion; (b) frozen composition; and (c) slip flow, showed satisfactory correspondence at all conditions except for qualities very close to saturated liquid. Observation was made that a condition similar to shock resulted when the nozzles were overexpanded.

Bounds on Two-Phase Flow: Part II — Void Fraction in Circular Pipes

2005 ◽  
Author(s):  
M. M. Awad ◽  
Y. S. Muzychka
Keyword(s):  
Experimental Data ◽  
Void Fraction ◽  
Mass Flow ◽  
Liquid Fraction ◽  
Published Data ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Working Fluids ◽  
Mass Flow Rates

Theoretical and empirical models for the gas void fraction (α) are reviewed. Simple rules are developed for obtaining rational bounds for the void fraction in two-phase flow. The lower bound is based on the separate cylinders formulation for turbulent-turbulent flow that uses the Blasius equation to predict the Fanning friction factor. The upper bound is based on the Butterworth relationship that represents well the Lockhart-Martinelli correlation. These two bounds are reversed in the case of liquid fraction (1−α). The bounds models are verified using published experimental data of void fraction versus mass quality at constant mass flow rate. The published data include different working fluids such as R-12 and R-22 at different pipe diameters, different pressures, and different mass flow rates. It is shown that the published data can be well bounded for a wide range of mass qualities, pipe diameters, pressures and mass flow rates. Further comparisons are made using the published experimental data of void fraction (α) and liquid fraction (1−α) versus the Lockhart-Martinelli parameter (X), for different working fluids such as R-12, R-22 and air-water mixtures.

Two-Phase Flow Behavior in Channels With Sudden Area Change Using Experimental and Computational Approach

2017 ◽  
Author(s):  
Ashish Kotwal ◽  
Che-Hao Yang ◽  
Clement Tang
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Experimental Analysis ◽  
Single Phase ◽  
Computational Analysis ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Area Change

The current study shows computational and experimental analysis of multiphase flows (gas-liquid two-phase flow) in channels with sudden area change. Four test sections used for sudden contraction and expansion of area in experiments and computational analysis. These are 0.5–0.375, 0.5–0.315, 0.5–0.19, 0.5–0.14, inversely true for expansion channels. Liquid Flow rates ranging from 0.005 kg/s to 0.03 kg/s employed, while gas flow rates ranging from 0.00049 kg/s to 0.029 kg/s implemented. First, single-phase flow consists of only water, and second two-phase Nitrogen-Water mixture flow analyzed experimentally and computationally. For Single-phase flow, two mathematical models used for comparison: the two transport equations k-epsilon turbulence model (K-Epsilon), and the five transport equations Reynolds stress turbulence interaction model (RSM). A Eulerian-Eulerian multiphase approach and the RSM mathematical model developed for two-phase gas-liquid flows based on current experimental data. As area changes, the pressure drop observed, which is directly proportional to the Reynolds number. The computational analysis can show precise prediction and a good agreement with experimental data when area ratio and pressure differences are smaller for laminar and turbulent flows in circular geometries. During two-phase flows, the pressure drop generated shows reasonable dependence on void fraction parameter, regardless of numerical analysis and experimental analysis.

Numerical Analysis of the Flow Inside a Centrifugal Compressor’s Vaneless Diffuser and Volute

2001 ◽  
Author(s):  
Hooman Rezaei ◽  
Abraham Engeda ◽  
Paul Haley
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Mass Flow ◽  
Operating Conditions ◽  
Vaneless Diffuser ◽  
Flow Angle ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Minimum Medium ◽  
Good Agreement

Abstract The objective of this work was to perform numerical analysis of the flow inside a modified single stage CVHF 1280 Trane centrifugal compressor’s vaneless diffuser and volute. Gambit was utilized to read the casing geometry and generating the vaneless diffuser. An unstructured mesh was generated for the path from vaneless diffuser inlet to conic diffuser outlet. At the same time a meanline analysis was performed corresponding to speeds and mass flow rates of the experimental data in order to obtain the absolute velocity and flow angle leaving the impeller for those operating conditions. These values and experimental data were used as inlet and outlet boundary conditions for the simulations. Simulations were performed in Fluent 5.0 for three speeds of 2000, 3000 and 3497 RPM and mass flow rates of minimum, medium and maximum. Results are in good agreement with the experimental ones and present the flow structures inside the vaneless diffuser and volute.

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

Study of Liquid Injection on Pressure Drop of Refrigerant Mixtures Inside Enhanced Surface Tubing

2005 ◽  
Author(s):  
S. M. Sami ◽  
J. Comeau
Keyword(s):  
Pressure Drop ◽  
Positive Impact ◽  
Reynolds Numbers ◽  
Two Phase ◽  
Flow Rates ◽  
Refrigerant Mixtures ◽  
Liquid Injection ◽  
Mass Flow Rates ◽  
Flow Pressure ◽  
Enhanced Surface

Two phase flow pressure drop characteristics observed under liquid injection during boiling of refrigerant mixtures R-404A, R407C and R507 as well as R-410A are presented in this paper. Experiments showed that liquid injection tends to decrease the pressure drop during boiling which will have positive impact in increasing the boiling heat transfer rate, heat flux and system efficiency. However, condensation data demonstrated that liquid injection increases the pressure drop. In addition, the data also reveals that the refrigerant under investigation exhibit the same behaviour at higher Reynolds numbers or mass flow rates.

Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 2 — Model Validation

2002 ◽  
Author(s):  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Cem Sarica ◽  
James P. Brill
Keyword(s):  
Experimental Data ◽  
Liquid Flow ◽  
Pipe Flow ◽  
Flow Behavior ◽  
Two Phase ◽  
Flow Rates ◽  
Inclination Angles ◽  
Gas Liquid Flow ◽  
Extensive Experimental Data ◽  
Good Agreement

In Zhang et al. [1], a unified hydrodynamic model is developed for prediction of gas-liquid pipe flow behavior based on slug dynamics. In this study, the new model is validated with extensive experimental data acquired with different pipe diameters, inclination angles, fluid physical properties, gas-liquid flow rates and flow patterns. Good agreement is observed in every aspect of the two-phase pipe flow.

Empirical Correlations for Sizing Adiabatic Capillary Tube Using LPG as Refrigerant in Split-Type Air-Conditioner

2014 ◽  
Vol 493 ◽  
pp. 99-104
Author(s):  
Shodiya Sulaimon ◽  
Azhar Abdul Aziz ◽  
Amer Nordin Darus ◽  
Henry Nasution
Keyword(s):  
Experimental Data ◽  
Mass Flow ◽  
Capillary Tube ◽  
Air Conditioner ◽  
Capillary Tubes ◽  
Two Phase ◽  
Design And Optimization ◽  
Mass Flow Rates ◽  
Inner Diameter ◽  
Vapour Compression

This paper presents correlations for sizing adiabatic capillary tubes which serves as an expansion device in split-type air-conditioner with LPG, novel hydrocarbon (HC) mixtures of butane (HC600) and propane (HC290) as refrigerant. A homogenous two-phase flow model developed by the authors and also experimental investigation of the Liquified Petroluem Gas (LPG) refrigerant flow in adiabatic capillary tubes were used in this study. The theoretical model was used to assess various percentage compositions of these HC mixtures and validated with the experimental data. For each HC refrigerant mixture, correlations for sizing adiabatic capillary tube which contains the relevant factors, viz. capillary tube inner diameter, inlet pressure, refrigerant mass flow rate, capillary tube surface roughness and capillary tube inlet subcooling was developed. The proposed correlations were compared with the authors measured data and found to be in good agreement. Further validation was made by comparing the mass flow rates predictions of the correlations with experimental data of previous studies and found that these correlations are consistent. The correlations can be used in small vapour compression refrigeration systems working with the HC refrigerant mixtures for practical design and optimization.

A Suggestion for Compressible Flow Graphs for use in Subsonic Flow

1966 ◽  
Vol 70 (670) ◽  
pp. 948-949
Author(s):  
L. J. S. Bradbury
Keyword(s):  
Compressible Flow ◽  
Static Pressure ◽  
Subsonic Flow ◽  
Flow Equation ◽  
Jet Flows ◽  
Flow Rates ◽  
Isentropic Expansion ◽  
Mass Flow Rates ◽  
Flow Graphs ◽  
Jet Blowing

The present re-look at compressible flow graphs arose during extensive testing of jet blowing models in low speed tunnels. In these tests, it is often necessary to calculate such quantities as jet thrusts, mass flow rates and velocities assuming isentropic expansion to the tunnel static pressure from the measured values of the stagnation pressure and temperature. These jet flows are usually compressible but subsonic and, in order to make these calculations, use has to be made either of Bernoulli's compressible flow equation or, alternatively, the extensive compressible flow graphs that are now available.

A NEW METHOD OF MEASURING TWO-PHASE MASS FLOW RATES IN A VENTURI

2009 ◽  
Vol 21 (1-2) ◽  
pp. 157-168 ◽  
Author(s):  
He Peixiang ◽  
Cees W. M. van der Geld ◽  
Claudio Alimonti ◽  
Julio Cesar Passos
Keyword(s):  
Mass Flow ◽  
New Method ◽  
Two Phase ◽  
Flow Rates ◽  
Mass Flow Rates

Expansion Waves in Two-Phase Pipelines

2006 ◽  
Author(s):  
Alessandro Terenzi
Keyword(s):  
Sound Velocity ◽  
Slip Flow ◽  
Expansion Wave ◽  
Two Phase ◽  
Expansion Waves ◽  
Internal Fluid ◽  
Pressurized Pipelines ◽  
The Impact ◽  
Phase Fluid ◽  
Wave Calculation

The analysis of the expansion wave propagation generated by full-bore ruptures of pressurized pipelines containing compressible fluids must be carried out during the assessment of the possible use of crack arrestors. If the internal fluid is two-phase, the sound velocity dependence from the local void fraction and flow regime has to be taken into account, by considering that it may be much lower than for single phase gases, thus promoting crack propagation. In this paper a model for the simulation of an expansion wave in a two-phase fluid pipeline is presented; this model includes several possible descriptions of the thermodynamics and flow regimes, ranging from the simpler homogeneous equilibrium approach to the non-equilibrium slip flow evaluation. The sound velocity trend inside a rarefaction wave can give rise to particular phenomena as curve inversions and jumps. The impact of different formulations on the expansion wave calculation is discussed, giving hints for the design of the pipelines under consideration.

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