Research on Characteristics of Spiral Flow Generator in a Horizontal Liquid-Solid Circulation Fluidized Bed

2012 ◽  
Vol 524-527 ◽  
pp. 1710-1714
Author(s):  
Yan Liu ◽  
Shao Feng Zhang ◽  
Wei Zhang
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Flow Direction ◽  
Axial Flow ◽  
Processing System ◽  
Spiral Flow ◽  
Pressure Losses ◽  
Flow Generator ◽  
Horizontal Circulation ◽  
Vane Angle

An experimental study is carried out to investigate the structure parameters and pressure drop characteristics of a spiral flow generator in a horizontal liquid-solid circulation fluidized bed. The CCD image measurement and data processing system was used to study the particles distribution at different angles covering 10°, 15°, 20°and 25°normal to the axial flow direction. Increasing the vane angle resulted in lower particles non-uniform results. The vane angle has important influence on generation of the spiral flow in horizontal circulation fluidized bed. The pressure loss with spiral flow generator is higher than that without spiral flow generator. The average increase in pressure losses was about 110% in comparison with that for the pipe without spiral flow generator. The vane angle of 15° represented the minimum pressure drop values.

Microchannels in series connected via a contraction/expansion section

2002 ◽  
Vol 459 ◽  
pp. 187-206 ◽  
Author(s):  
WING YIN LEE ◽  
MAN WONG ◽  
YITSHAK ZOHAR
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Flow Direction ◽  
Pressure Sensors ◽  
Narrow Channel ◽  
Narrow Channels ◽  
Pressure Losses ◽  
Transition Section ◽  
In Series ◽  
Straight Segments

Fluid flow in microdevices consisting of pairs of microchannels in series was studied. The dimensions of the channels are about 40 μm × 1 μm × 2000 μm for the wide and about 20 μm × 1 μm × 2000 μm for the narrow channels. Pairs of wide and narrow channels, with integrated pressure sensors, are connected via transition sections with included angles varying from 5° to 180°. Minor pressure losses (not due to friction) were studied by passing nitrogen through the channels under inlet pressures up to 60 p.s.i. Each device was tested in the contraction mode, flow from wide to narrow channel, and in the opposite expansion mode, flow from narrow to wide channel. Mass flow rate was first measured as a function of the overall pressure drop. The detailed pressure distribution along the straight segments and around the transition section was then measured in order to understand the flow pattern. The Reynolds number for these flows is less than 1, suggesting the flow to be of the Hele-Shaw type with no separation such that the results for all the devices should be similar. However, the flow rate was found to decrease and the pressure loss to increase significantly with increasing included angle of the transition section, regardless of the flow direction. Flow separation due to the transition sections, if indeed there is any, cannot explain the large pressure drop since the kinetic energy is negligible.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

Monitoring of the fluidized bed particle drying process by temperature and pressure drop measurements

2021 ◽  
pp. 1-13
Author(s):  
Gabriela Saldanha Soares ◽  
Scarlet Neves Tuchtenhagen ◽  
Luiz Antonio de Almeida Pinto ◽  
Carlos Alberto Severo Felipe
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Drying Process ◽  
Temperature And Pressure

Paper 10: Pressure Losses in the Inlet and Outlet Casings of Axial Flow Turbines for Turbo-Chargers

1967 ◽  
Vol 182 (4) ◽  
pp. 71-79 ◽  
Author(s):  
C. W. Simpson ◽  
D. E. Y. Scarlett
Keyword(s):  
Axial Flow ◽  
Annular Nozzle ◽  
Design Studies ◽  
Pressure Losses ◽  
Pressure Loss Coefficient ◽  
Turbine Efficiency ◽  
Annular Section ◽  
Turbine Casing ◽  
Transition Piece ◽  
Experimental Pressure

During initial design studies for a new range of turbo-chargers it was apparent that a considerable gain of efficiency could be achieved by a reduction of turbine casing losses. In this paper the theoretical and experimental pressure losses obtained from rig tests on the inlet and outlet casings for old and new designs will be presented. The inlet casing tests were completed on an axial entry casing with transition from circular to semi-annular section. The effect of this transition piece on gas incidences is also shown for the semi-annular nozzle entry. Studies on the outlet casing as a transition from annular through radial to axial flow have been completed and will be presented as a pressure loss coefficient for various designs. The tests have been undertaken with both convex and flat plate radial diffusers, with or without swirl. Different outlet ducts were used to determine the effects on pressure losses in the casings, and the results are discussed. Finally, the gains in overall turbine efficiency obtained by adopting the beneficial results from these tests are considered.

Annular Frictional Pressure Losses During Drilling—Predicting the Effect of Drillstring Rotation

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Arild Saasen
Keyword(s):  
Rheological Properties ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Axial Flow ◽  
Drilling Fluids ◽  
Unstable Flow ◽  
Pressure Losses ◽  
Shear Dependent Viscosity ◽  
Water Based ◽  
Dependent Viscosity

Controlling the annular frictional pressure losses is important in order to drill safely with overpressure without fracturing the formation. To predict these pressure losses, however, is not straightforward. First of all, the pressure losses depend on the annulus eccentricity. Moving the drillstring to the wall generates a wider flow channel in part of the annulus which reduces the frictional pressure losses significantly. The drillstring motion itself also affects the pressure loss significantly. The drillstring rotation, even for fairly small rotation rates, creates unstable flow and sometimes turbulence in the annulus even without axial flow. Transversal motion of the drillstring creates vortices that destabilize the flow. Consequently, the annular frictional pressure loss is increased even though the drilling fluid becomes thinner because of added shear rate. Naturally, the rheological properties of the drilling fluid play an important role. These rheological properties include more properties than the viscosity as measured by API procedures. It is impossible to use the same frictional pressure loss model for water based and oil based drilling fluids even if their viscosity profile is equal because of the different ways these fluids build viscosity. Water based drilling fluids are normally constructed as a polymer solution while the oil based are combinations of emulsions and dispersions. Furthermore, within both water based and oil based drilling fluids there are functional differences. These differences may be sufficiently large to require different models for two water based drilling fluids built with different types of polymers. In addition to these phenomena washouts and tool joints will create localised pressure losses. These localised pressure losses will again be coupled with the rheological properties of the drilling fluids. In this paper, all the above mentioned phenomena and their consequences for annular pressure losses will be discussed in detail. North Sea field data is used as an example. It is not straightforward to build general annular pressure loss models. This argument is based on flow stability analysis and the consequences of using drilling fluids with different rheological properties. These different rheological properties include shear dependent viscosity, elongational viscosity and other viscoelastic properties.

Effects of Rib Arrangements on Pressure Drop and Heat Transfer in a Rib-Roughened Channel With a Sharp 180 deg Turn

1997 ◽  
Vol 119 (3) ◽  
pp. 610-616 ◽  
Author(s):  
S. Mochizuki ◽  
A. Murata ◽  
M. Fukunaga
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Secondary Flow ◽  
Flow Direction ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Diameter Ratio ◽  
Equivalent Diameter ◽  
Before And After ◽  
Rib Roughened

The objective of this study was to investigate, through experiments, the combined effects of a sharp 180 deg turn and rib patterns on the pressure drop performance and distributions of the local heat transfer coefficient in an entire two-pass rib-roughened channel with a 180 deg turn. The rib pitch-to-equivalent diameter ratio P/de was 1.0, the rib-height-to-equivalent diameter ratio e/de was 0.09, and the rib angle relative to the main flow direction was varied from 30 ∼ 90 deg with an interval of 15 deg. Experiments were conducted for Reynolds numbers in the range 4000 ∼ 30,000. It was disclosed that, due to the interactions between the bend-induced secondary flow and the rib-induced secondary flow, the combination of rib patterns in the channel before and after the turn causes considerable differences in the pressure drop and heat transfer performance of the entire channel.

Experimental Study of the Mixing and Segregation Behavior in Binary Particle Fluidized Bed with Wide Size Distributions

2018 ◽  
Vol 16 (12) ◽  
Author(s):  
Runjia Liu ◽  
Yong Zang ◽  
Rui Xiao
Keyword(s):  
Image Processing ◽  
Pressure Drop ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Processing Method ◽  
Size Distributions ◽  
Mixing Index ◽  
Image Processing Method ◽  
Segregation Behavior ◽  
Wide Size Distribution

Abstract Detailed understanding the particle mixing and segregation dynamic is essential in successfully designing and reasonably operating multicomponent fluidized bed. In this work, a novel fluorescent tracer technique combining image processing method has been used to investigate the mixing and segregation behavior in a binary fluidized bed with wide size distributions. The particle number percentage in each layer for different gas velocities is obtained by an image processing method. Fluidization, mixing and segregation behavior has been discussed in terms of bed pressure drop, gas velocity and mixing index. Different types of binary particle systems, including the jetsam and the flotsam-rich system, are analyzed and compared. The mixing indexes at different minimum fluidization velocities are also analyzed and compared with other work. The results show that the theoretical minimum fluidization velocity calculated from the bed pressure drop cannot represent the whole fluidization for a wide size distribution binary particle system. The effect of a wide size distribution is an inflection point in the mixing index curve. There is also a dead region in the bottom of the bed that consists of particles with large size and a low degree of sphericity. The particles in the dead region are extraordinarily difficult to fluidize and should be considered in the design of fluidized beds in industrial applications.

Numerical Simulation on Heat Transfer and Fluid Flow Characteristics of Arrays With Nonuniform Plate Length Positioned Obliquely to the Flow Direction

1998 ◽  
Vol 120 (4) ◽  
pp. 991-998 ◽  
Author(s):  
L. B. Wang ◽  
G. D. Jiang ◽  
W. Q. Tao ◽  
H. Ozoe
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Direction ◽  
Flow Characteristics ◽  
Numerical Results ◽  
The Body ◽  
Number Range ◽  
Plate Length ◽  
Nonuniform Plate ◽  
Short Plate

The periodically fully developed laminar heat transfer and pressure drop of arrays with nonuniform plate length aligned at an angle (25 deg) to air direction have been investigated by numerical analysis in the Reynolds number range of 50–1700. The body-fitted coordinate system generated by the multisurface method was adopted to retain the corresponding periodic relation of the lines in physical and computational domains. The computations were carried out just in one cycle. Numerical results show that both the heat transfer and pressure drop increase with the increase in the length ratio of the long plate to the short plate, and decrease with the decrease in the ratio of transverse pitch to the longitudinal pitch. The numerical results exhibit good agreement with available experimental data.

Effect of Tube Diameter on Flow Phenomena of Gas-Liquid Two-Phase Flow in Microchannels

2015 ◽  
Author(s):  
Hideo Ide ◽  
Eiji Kinoshita ◽  
Ryo Kuroshima ◽  
Takeshi Ohtaka ◽  
Yuichi Shibata ◽  
...  
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Water Solution ◽  
Flow Direction ◽  
Flow Characteristics ◽  
Tube Diameter ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Flow Phenomena ◽  
The Waves

Gas-liquid two-phase flows in minichannels and microchannels display a unique flow pattern called ring film flow, in which stable waves of relatively large amplitudes appear at seemingly regular intervals and propagate in the flow direction. In the present work, the velocity characteristics of gas slugs, ring films, and their features such as the gas slug length, flow phenomena and frictional pressure drop for nitrogen-distilled water and nitrogen-30 wt% ethanol water solution have been investigated experimentally. Four kinds of circular microchannels with diameters of 100 μm, 150 μm, 250 μm and 518 μm were used. The effects of tube diameter and physical properties, especially the surface tension and liquid viscosity, on the flow patterns, gas slug length and the two-phase frictional pressure drop have been investigated by using a high speed camera at 6,000 frames per second. The flow characteristics of gas slugs, liquid slugs and the waves of ring film are presented in this paper.

Sign in / Sign up

Export Citation Format

Share Document