The Flow Conditions to Move Different Plastic Particles in Dilute Pneumatic Conveying

2011 ◽  
Vol 148-149 ◽  
pp. 932-937
Author(s):  
Rungtawan Wiwattanasirikul ◽  
Purimpat Sujumnongtokul
Keyword(s):  
Unit Length ◽  
Positive Pressure ◽  
Pneumatic Conveying ◽  
Flow Conditions ◽  
Test Rig ◽  
Air Velocity ◽  
Two Phase ◽  
Inner Diameter ◽  
Minimum Velocity ◽  
Total Test

In this research, positive-pressure high velocity pneumatic conveying has been tested to determine the flow conditions such as minimum velocity, solid mass flow rate, and pressure drop per unit length of polypropylene (PP), recycled polyethylene (recycled PE), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). The conveying efficiency (η ) of such two-phase flow was also experimentally investigated. During the course of the experimental conduct, the material sphericity ranged from 73.2 to 84.4 %. True density ranged from 904.5 to 1305.7 kg/m3, and bulk density covered the range of 493.7 to 783.4 kg/m3 .The tests were carried out on a pneumatic conveying test rig using a PVC pipes of 0.079-m inner diameter and total test length of 8.57 m. The results showed the minimum conditions to move the particles in dilute phase. For the conveying efficiency (η), the efficiency varies reversely with the air velocity in exponential function.

An Experimental Study of Horizontal Self-Excited Pneumatic Conveying

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Fei Yan ◽  
Akira Rinoshika
Keyword(s):  
Pressure Drop ◽  
Power Consumption ◽  
Pneumatic Conveying ◽  
Velocity Range ◽  
Air Velocity ◽  
Additional Pressure ◽  
Polyethylene Particles ◽  
Conveying System ◽  
Frequency Features ◽  
Minimum Velocity

A new pneumatic conveying system that applies soft fins mounted vertically on a center plane of pipe in the inlet of the gas-particle mixture is developed to reduce power consumption and conveying velocity. The effect of different fin’s lengths on a horizontal pneumatic conveying is experimentally studied in terms of the pressure drop, conveying velocity, power consumption, particle flow pattern, and additional pressure drop. The test pipeline consisted of a horizontal smooth acrylic tube with an inside diameter of 80 mm and a length of about 5 m. Two kinds of polyethylene particles with diameters of 2.3 mm and 3.3 mm are used as conveying materials. The superficial air velocity is varied from 10 to 17 m/s, and the solid mass flow rate is from 0.20 to 0.45 kg/s. Compared with conventional pneumatic conveying, the pressure drop, minimum and critical velocities, power consumption, and additional pressure drop can be reduced by using soft fins in a lower air velocity range, and the efficiency of fins becomes more evident when increasing the length of the fins or touching particles stream by the long fins. The maximum reduction rates of the minimum velocity and power consumption by using soft fins are about 20% and 31.5%, respectively. The particle concentrations of using fins are lower than those of non-fin near the bottom of the pipe and are higher than those of non-fin in the upper part of the pipe in the acceleration region. Based on analyzing the frequency features of the fin’s oscillation, the Strouhal number of more efficient fins is about St ≈ 0.75 in the air velocity range of lower than 13 m/s.

scholarly journals Experimental Analysis of Gas–Liquid–Solid Three-Phase Flows in Horizontal Pipelines

2020 ◽  
Vol 105 (4) ◽  
pp. 1035-1054
Author(s):  
Paolo Sassi ◽  
Youssef Stiriba ◽  
Julia Lobera ◽  
Virginia Palero ◽  
Jordi Pallarès
Keyword(s):  
Flow Visualization ◽  
Flow Regime ◽  
Solid Particles ◽  
High Complexity ◽  
Flow Conditions ◽  
Two Phase Flows ◽  
Two Phase ◽  
Three Phase ◽  
Inner Diameter ◽  
The Individual

AbstractThe dynamics of three-phase flows involves phenomena of high complexity whose characterization is of great interest for different sectors of the worldwide industry. In order to move forward in the fundamental knowledge of the behavior of three-phase flows, new experimental data has been obtained in a facility specially designed for flow visualization and for measuring key parameters. These are (1) the flow regime, (2) the superficial velocities or rates of the individual phases; and (3) the frictional pressure loss. Flow visualization and pressure measurements are performed for two and three-phase flows in horizontal 30 mm inner diameter and 4.5 m long transparent acrylic pipes. A total of 134 flow conditions are analyzed and presented, including plug and slug flows in air–water two-phase flows and air–water-polypropylene (pellets) three-phase flows. For two-phase flows the transition from plug to slug flow agrees with the flow regime maps available in the literature. However, for three phase flows, a progressive displacement towards higher gas superficial velocities is found as the solid concentration is increased. The performance of a modified Lockhart–Martinelli correlation is tested for predicting frictional pressure gradient of three-phase flows with solid particles less dense than the liquid.

Performance and pressure distribution changes in a centrifugal pump under two-phase flow

1998 ◽  
Vol 212 (3) ◽  
pp. 165-171 ◽  
Author(s):  
E T Pak ◽  
J C Lee
Keyword(s):  
Pressure Gradient ◽  
Pressure Distribution ◽  
Centrifugal Pump ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Positive Pressure ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Pump Performance

Pump performance characteristics change drastically under two-phase flow conditions from those of single-phase flow. This is due to a change in flow characteristics in the impeller. Owing to a positive pressure gradient the air bubble moves more slowly than the water in the impeller channel, but in the suction surface region of the impeller inlet, where a negative pressure gradient prevails, the bubbles move more quickly than the water. Thus, in the space just after this region the distributions of the void fraction obtained are considerably higher and uneven. The change in the pressure distribution owing to air admission is also particularly evident in the inlet region of the impeller. These changes bring about an alteration of the whole flow pattern in the impeller and also cause a drop in pump performance. The Reynolds-averaged Navier-Stokes equations for two-phase flow in a centrifugal pump impeller are solved using a finite volume method to obtain the pressure, velocities and void fraction respectively. Good agreement is achieved when the predicted results are compared with those measured experimentally within the range of bubbly flow conditions.

scholarly journals Experimental investigation of hydrodynamic phenomena in vertical-upward adiabatic two-phase flow conditions

2021 ◽  
Vol 10 (3) ◽  
pp. 49-59
Author(s):  
Dinh Anh Tuan ◽  
Pham Tuan Nam ◽  
Nguyen Tu Oanh
Keyword(s):  
Experimental Investigation ◽  
Atmospheric Pressure ◽  
Two Phase Flow ◽  
Water Velocity ◽  
Phase Flow ◽  
Flow Conditions ◽  
Air Velocity ◽  
Two Phase ◽  
Single Flow ◽  
Flow Experiments

In order to investigate hydrodynamic phenomena in two-phase flow conditions in nuclear safety analysis, a series of two-phase flow experiments were conducted using a single flow channel in which air and water were simultaneously injected into the test section. The experiments under atmospheric pressure conditions were carried out with the water velocity and the air velocity covering the ranges from 0.2 to 1.5 m/s and 0.05 to 0.2 m/s, respectively. The technique of two-sensor conductivity probe was used for the measurement of bubble parameters. The experimental results presented and analyzed in this study are the local time-averaged void fraction and bubble velocities at three axial positions L/D = 14.4, 51.2 and 71.3.

An Experimental Study With Minimum Transport Velocity of Dilute Gas-Solid Two-Phase Flow in a Vertical Pipe

2003 ◽  
Author(s):  
Mitsuaki Ochi ◽  
Hiroshi Nishimura ◽  
Masahiro Takei
Keyword(s):  
Empirical Equation ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Vertical Pipe ◽  
Air Velocity ◽  
Two Phase ◽  
Dilute Gas ◽  
Transport Velocity ◽  
Transport Experiment ◽  
Minimum Velocity

A simple empirical equation of the minimum transport velocity of a dilute two-phase flow for granular solids in a vertical pipe has been derived on the basis of both a dynamic model equation and the transport experiment. The minimum transport velocity means here the limiting air velocity at which conveying is possible in a state in which particles are not stagnant or recircular in the pipe. As a result, it is found that the empirical equation of the minimum transport velocity, simply called the minimum velocity, can arrange the data of this study with a pretty good accuracy.

Mass Transfer in Single Bends Under Annular Two Phase Flow Conditions

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
H. Mazhar ◽  
D. Ewing ◽  
J. S. Cotton ◽  
C. Y. Ching
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Rate ◽  
Local Maximum ◽  
Outer Wall ◽  
Water Velocity ◽  
Maximum Mass ◽  
Flow Conditions ◽  
Air Velocity ◽  
Two Phase ◽  
Transfer Rates

The distributions of the mass transfer coefficient in horizontal 90 deg bends were measured under a range of two phase annular flow conditions. A dissolving wall technique at a high Schmidt number (Sc = 1280) is used for the measurements. The maximum mass transfer occurred on the centerline of the bend outer wall at an angle of approximately 50 deg from the bend inlet under all tested conditions. The area of maximum mass transfer rate was found to span approximately 30 deg in the circumferential direction. A second region of enhanced mass transfer occurred on the latter part of the bend with a local maximum occurring slightly off the bend centerline in some cases. Changing the air and water superficial velocities (Jv = 22–30 m/s, JL = 0.17–0.41 m/s) showed that the air velocity had a larger effect on the mass transfer rates than the water velocity; however, the effect of the water velocity on the mass transfer was not insignificant.

Flow Accelerated Corrosion in Single Bends Under Annular Two Phase Flow Conditions

2012 ◽  
Author(s):  
H. Mazhar ◽  
D. Ewing ◽  
J. S. Cotton ◽  
C. Schefski ◽  
C. Y. Ching
Keyword(s):  
Mass Transfer ◽  
Local Maximum ◽  
Outer Wall ◽  
Water Velocity ◽  
Maximum Mass ◽  
Flow Conditions ◽  
Air Velocity ◽  
Two Phase ◽  
Accelerated Corrosion ◽  
Flow Accelerated Corrosion

The distributions of the mass transfer coefficient in horizontal 90 degree bends were measured under a range of two phase annular flow conditions. A dissolving wall technique at a high Schmidt number (Sc = 1280) is used for the measurements. The maximum mass transfer occurred on the centerline of the bend outer wall at an angle of approximately 50 degrees from the bend inlet under all tested conditions. The area of maximum mass transfer was found to span approximately 30 degrees in the circumferential direction. A second region of enhanced mass transfer occurred on the latter part of the bend with a local maximum occurring slightly off the bend centerline in some cases. Changing the air and water superficial velocities (Jν = 20 to 30 m/s, JL = 0.17 to 0.41 m/s) showed that the air velocity had a larger effect on the mass transfer than the water velocity; however the effect of the water velocity on the mass transfer was not insignificant.

scholarly journals Numerical simulation of air–water two–phase flow in vertical pipe using k-ε model

2015 ◽  
Vol 4 (1) ◽  
pp. 61 ◽  
Author(s):  
Ali Sanati
Keyword(s):  
Two Phase Flow ◽  
Numerical Data ◽  
Phase Flow ◽  
Gas Velocity ◽  
Flow Conditions ◽  
Empirical Correlations ◽  
Vertical Pipe ◽  
Air Velocity ◽  
Two Phase ◽  
Flow Through

Two-phase flow exists mostly in pipes and is of substantial importance in pipeline industry. Numerical data are presented in this paper for water and air velocity in two-phase flow through vertical circular channel using both K-ε model and empirical correlations. In order to investigate the pressure distribution for various flow conditions, two-phase flow was considered through two vertical pipes with different lengths and the same diameters. Moreover, we studied flow entering from below and getting out from top of the pipe. Results obtained in this study have been analyzed with experimental data, showing that the average void fraction rises with increasing inlet gas velocity and drops with increasing inlet water velocity. Also results show that Hassan & Kabir method is the most appropriate approach in comparison with the others.

Sign in / Sign up

Export Citation Format

Share Document