A Study on the Flow Pattern Within the Centrifugal and Mixed-Flow Impellers

1971 ◽  
Author(s):  
Shinpei Mizuki ◽  
Toshimichi Sakai ◽  
Ichiro Watanabe
Keyword(s):  
Experimental Data ◽  
Flow Pattern ◽  
Surface Pressure ◽  
Flow Behavior ◽  
Inviscid Flow ◽  
Flow Patterns ◽  
Blade Surface ◽  
Mixed Flow ◽  
Analytical Results ◽  
Good Coincidence

An Investigation of the flow patterns within the centrifugal and mixed-flow impeller channel were performed. The velocity distributions within the impeller channel and blade surface pressure of the centrifugal and mixed-flow impellers were closely examined by experiment and the flow behavior within these impellers were clarified. The incompressible and inviscid flow within the impellers having straight radial blades were also derived analytically. The present authors assumed an outermost boundary of the relative eddy at the impeller exit periphery and corrected the analytical results. The corrected analytical results thus obtained showed good coincidence with the experimental data.

A New Model for Dispersed Multi-Layer Oil-Water Flow

2001 ◽  
Author(s):  
Subash S. Jayawardena ◽  
Banu Alkaya ◽  
Clifford L. Redus ◽  
James P. Brill
Keyword(s):  
Flow Pattern ◽  
Fluid Model ◽  
Flow Behavior ◽  
Mechanistic Model ◽  
Homogeneous Model ◽  
Flow Patterns ◽  
New Model ◽  
Oil In Water ◽  
Oil Water ◽  
Liquid Flows

Abstract Flow patterns observed in near-horizontal oil-water two-phase flows are quite different from those in gas-liquid flows. Experience with gas-liquid flows suggests that the mechanisms governing the flow behavior are flow-pattern dependent. However, little attention has been given to modeling flow patterns observed only in liquid-liquid systems. Such flow patterns include an oil-in-water dispersion flowing on top of a water layer and the simultaneous flow of dispersions of water-in-oil and oil-in-water as separate layers. A new mechanistic model is developed for one such flow pattern in horizontal and near-horizontal pipelines. The model combined the two-fluid model used for stratified flows with the homogeneous model used for dispersed flows. This paper presents that model, and shows that the new model can predict the pressure gradient as well as the holdup. The model results are compared with those from two other models, the stratified flow model and the homogeneous model. The new model predictions are also compared with available experimental data.

Analysis of Leakage Flow Through the Flank Contacts in Transition Zone in Involute External Toothed Gear Pump

2017 ◽  
Author(s):  
Vineet Sahoo ◽  
Debanshu Roy ◽  
Rathindranath Maiti
Keyword(s):  
Flow Pattern ◽  
Transition Zone ◽  
Fluid Pressure ◽  
Flow Patterns ◽  
Leakage Flow ◽  
Gear Pump ◽  
Instantaneous Flow ◽  
Analytical Results ◽  
Basic Purpose ◽  
Flow Through

The leakage past the tooth flanks of the gears in transition contacts in involute external toothed gear pump is analyzed in details using CFD in Fluent®. Analytical results support the experimentally visualized flow patterns [1]. Extending the approach of an earlier investigation [2] more rigorous analyses are carried out considering actual gear data of a pump and a full cycle of contact. However, the relieve groove and cavitation are not considered. The basic purpose is to establish the flow pattern analyses using CFD in Fluent-Ansys® environment. The beginning and the end of entrapment, squeezing of fluid, pressure build up, separation and generation of gap at the active contact and instantaneous flow through the gap are estimated meticulously.

Flow Pattern and Boiling Heat Transfer of CO2 at High Pressure in Horizontal Mini-Channels

2010 ◽  
Author(s):  
Takeyuki Ami ◽  
Noriko Nakamura ◽  
Hisashi Umekawa ◽  
Mamoru Ozawa ◽  
Masahiro Shoji
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Flow Pattern ◽  
Void Fraction ◽  
Boiling Heat Transfer ◽  
Flow Behavior ◽  
Nucleate Boiling ◽  
Flow Patterns ◽  
Heat Transfer Deterioration ◽  
Mini Channels

Experimental investigation was conducted with CO2 at high pressure, ranging 5.0 to 6.5 MPa, in horizontal mini-channels of 0.51, 1.0 and 2.0 mm in diameters. In smaller bores tube, e.g. 0.51 and 1.0 mm, the phase stratification is not serious and the flow pattern becomes quasi-axi-symmetric, while in 2.0 mm or larger tubes phase stratification becomes significant as in conventional sized tubes. This phase stratification, together with the intermittent flow behavior, causes the heat transfer deterioration at the upper wall. Existing criteria as a whole were insufficient in predicting flow patterns. In order to predict complicated two-phase flow behavior, including inherent void fraction fluctuation and flow patterns, the discrete bubble model based on a pattern dynamics approach was developed, so as to be applicable to the horizontal mini-channels. The simulated void fraction fluctuations successfully provided not only the flow pattern maps in terms of statistical properties, but also quantitative estimation of the heat transfer deterioration at the upper wall of the tube of 2.0 mm in diameter. Existing correlations were evaluated through the comparison with the present experimental data, and a nucleate boiling mode was found a dominant mode over the boiling heat transfer at high pressure in mini-channels.

scholarly journals The Flow Pattern Transition and Water Holdup of Gas–Liquid Flow in the Horizontal and Vertical Sections of a Continuous Transportation Pipe

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2077
Author(s):  
Guishan Ren ◽  
Dangke Ge ◽  
Peng Li ◽  
Xuemei Chen ◽  
Xuhui Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Pattern ◽  
Liquid Mixture ◽  
Vertical Section ◽  
Flow Patterns ◽  
Phase Flow ◽  
Three Phase ◽  
Three Phase Flow ◽  
Oil Water ◽  
Water Gas

A series of experiments were conducted to investigate the flow pattern transitions and water holdup during oil–water–gas three-phase flow considering both a horizontal section and a vertical section of a transportation pipe simultaneously. The flowing media were white mineral oil, distilled water, and air. Dimensionless numbers controlling the multiphase flow were deduced to understand the scaling law of the flow process. The oil–water–gas three-phase flow was simplified as the two-phase flow of a gas and liquid mixture. Based on the experimental data, flow pattern maps were constructed in terms of the Reynolds number and the ratio of the superficial velocity of the gas to that of the liquid mixture for different Froude numbers. The original contributions of this work are that the relationship between the transient water holdup and the changes of the flow patterns in a transportation pipe with horizontal and vertical sections is established, providing a basis for judging the flow patterns in pipes in engineering practice. A dimensionless power-law correlation for the water holdup in the vertical section is presented based on the experimental data. The correlation can provide theoretical support for the design of oil and gas transport pipelines in industrial applications.

Calculation of Compressible Subsonic Flow in Cascades With Varying Blade Height

1973 ◽  
Vol 95 (4) ◽  
pp. 345-351 ◽  
Author(s):  
R. A. Van den Braembussche
Keyword(s):  
Experimental Data ◽  
Subsonic Flow ◽  
Rotational Flow ◽  
Blade Surface ◽  
Mixed Flow ◽  
Exact Relation ◽  
Blade Height ◽  
Singularity Method ◽  
Turbine Cascades ◽  
Theoretical Results

This paper deals with a singularity method to calculate the subsonic compressible flow in compressor and turbine cascades, with constant or varying blade height. The method is an extension of an incompressible flow method by means of the Janzen-Rayleigh theorem, using an exact relation between pressure and density. Theoretical results are compared with experimental data. A further extension of this method to rotational flow in plane cascades obtained from the transformation of the blade to blade surface of a mixed flow machine is also discussed.

Average Physical Parameters in an Air-Water Two-Phase Flow in a Small, Square-Sectioned Channel

1994 ◽  
Vol 116 (2) ◽  
pp. 247-254 ◽  
Author(s):  
J. K. Keska ◽  
R. D. Fernando
Keyword(s):  
Experimental Data ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Full Range ◽  
Flow Patterns ◽  
Physical Parameters ◽  
Phase Flow ◽  
Spatial Concentration ◽  
Two Phase ◽  
Concentration Measurements

This experimental study focuses on an adiabatic two-phase air-water flow generated in a small, horizontal, 6.35 mm square channel. Pressure and temperature were near standard conditions. Experimental data and correlations available in the literature, generally, do not consider the full range of concentration, small cross-sectional areas and direct physical parameters, such as concentration (void fraction) and/or phase velocities. Based on the direct measurement of in-situ spatial concentration (in a full range of concentrations, including gas and liquid phases only), and flow-pattern determination, the experimental data from the study are compared with data from the literature and with prediction by the generally accepted Lockhart-Martinelli’s and Chen’s models. Spatial concentration measurements were made with a computer-based system developed and built by the authors. Pressure drop over a length of the channel was also measured with pressure transducers. These measurements were made for a variety of flow conditions which encompassed bubble, slug, plug, and annular flow regimes. Flow patterns were established, and both mean and fluctuating components of the concentration measurements were used to objectively identify the flow patterns. These results, together with visual enhanced observation (stroboscope) supplemented with a high-speed CCD camera recording enhanced with dye injection, were used to obtain flow-pattern maps and compared with the literature. Spatial concentration is shown to be a key physical parameter in describing the state of the mixture in two-phase flow.

Prediction of Unsteady Rotor-Surface Pressure and Heat Transfer From Wake Passings

1992 ◽  
Vol 114 (4) ◽  
pp. 807-817 ◽  
Author(s):  
L. T. Tran ◽  
D. B. Taulbee
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Boundary Layer ◽  
Heat Flux ◽  
Unsteady Flow ◽  
Rotor Blade ◽  
Numerical Solutions ◽  
Inviscid Flow ◽  
Blade Surface ◽  
Blade Passage

The research described in this paper is a numerical investigation of the effects of unsteady flow on gas turbine heat transfer, particularly on a rotor blade surface. The unsteady flow in a rotor blade passage and the unsteady heat transfer on the blade surface as a result of wake/blade interaction are modeled by the inviscid flow/boundary layer approach. The Euler equations that govern the inviscid flow are solved using a time-accurate marching scheme. The unsteady flow in the blade passage is induced by periodically moving a wake model across the passage inlet. Unsteady flow solutions in the passage provide pressure gradients and boundary conditions for the boundary-layer equations that govern the viscous flow adjacent to the blade surface. Numerical solutions of the unsteady turbulent boundary layer yield surface heat flux values that can then be compared to experimental data. Comparisons with experimental data show that unsteady heat flux on the blade suction surface is well predicted, but the predictions of unsteady heat flux on the blade pressure surface do not agree.

scholarly journals Numerical Investigation of Flow Characteristics of Molten Steel in the Tundish with Channel Induction Heating

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1937
Author(s):  
Bin Yang ◽  
Hong Lei ◽  
Yingshi Xu ◽  
Kun Liu ◽  
Peng Han
Keyword(s):  
Fluid Flow ◽  
Flow Pattern ◽  
Numerical Investigation ◽  
Induction Heating ◽  
Molten Steel ◽  
Flow Behavior ◽  
Plug Flow ◽  
Flow Characteristics ◽  
Main Flow ◽  
Mixed Flow

In the continuous process, fluid flow is an important physical phenomena in the tundish, as it affects the process of heat transfer, bubble motion and inclusion collision-coalescence and grow up. This paper undertakes a detailed numerical investigation of fluid flow characteristics in the tundish with and without induction heating. The individual unit method and the volume subtraction model are applied to analyze the flow characteristics. A quantitative evaluation method of flow characteristics is proposed to investigate the flow characteristics. In the tundish with and without induction heating, firstly, the main flow behavior of molten steel is mixed flow in the receiving chamber; secondly, the main flow behavior of molten steel is plug flow in the channel; lastly, the main flow pattern is mixed flow, and the minor flow pattern is plug flow in the discharging chamber. The method of the volume subtraction model is an effective way to analyze the flow characteristics in the tundish with channel induction heating.

Prediction of Unsteady Rotor-Surface Pressure and Heat Transfer From Wake Passings

1991 ◽  
Author(s):  
Le T. Tran ◽  
Dale B. Taulbee
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Boundary Layer ◽  
Heat Flux ◽  
Unsteady Flow ◽  
Rotor Blade ◽  
Numerical Solutions ◽  
Inviscid Flow ◽  
Blade Surface ◽  
Blade Passage

The research described in this paper is a numerical investigation of the effects of unsteady flow on gas turbine heat transfer, particularly on a rotor blade surface. The unsteady flow in a rotor blade passage and the unsteady heat transfer on the blade surface as a result of wake/blade interaction are modeled by the inviscid flow/boundary layer approach. The Euler equations which govern the inviscid flow are solved using a time accurate marching scheme. The unsteady flow in the blade passage is induced by periodically moving a wake model across the passage inlet. Unsteady flow solutions in the passage provide pressure gradients and boundary conditions for the boundary-layer equations which govern the viscous flow adjacent to the blade surface. Numerical solutions of the unsteady turbulent boundary layer yield surface heat flux values which can then be compared to experimental data. Comparisons with experimental data show that unsteady heat flux on the blade suction surface is well predicted, but the predictions of unsteady heat flux on the blade pressure surface do not agree.

scholarly journals Flow Pattern Map of Flow Boiling in a Rectangular Channel Filled with Porous Media

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2440
Author(s):  
Youngwoo Kim ◽  
Dae Yeon Kim ◽  
Kyung Chun Kim
Keyword(s):  
Porous Media ◽  
Flow Pattern ◽  
Flow Regime ◽  
Annular Flow ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Flow Patterns ◽  
Flow Pattern Map ◽  
Mist Flow ◽  
Churn Flow

A flow visualization study was carried out for flow boiling in a rectangular channel filled with and without metallic random porous media. Four main flow patterns are observed as intermittent slug-churn flow, churn-annular flow, annular-mist flow, and mist flow regimes. These flow patterns are clearly classified based on the high-speed images of the channel flow. The results of the flow pattern map according to the mass flow rate were presented using saturation temperatures and the materials of porous media as variables. As the saturation temperatures increased, the annular-mist flow regime occupied a larger area than the lower saturation temperatures condition. Therefore, the churn flow regime is narrower, and the slug flow more quickly turns to annular flow with the increasing vapor quality. The pattern map is not significantly affected by the materials of porous media.

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