Effects of flow speed, flow pattern and air bubbles on pressure loss in slurry pipelines

2003 ◽  
Vol 20 (1) ◽  
pp. 36-41
Author(s):  
Wang Xinli ◽  
J. Y. Hwang ◽  
R. C. Greenlund ◽  
Xiaodi Huang ◽  
A. M. Hein
Keyword(s):  
Flow Pattern ◽  
Pressure Loss ◽  
Flow Speed ◽  
Air Bubbles ◽  
Speed Flow

scholarly journals Modelling Free Flow Speed on Two-Lane Rural Highways in Bosnia and Herzegovina

2014 ◽  
Vol 26 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Ivan Lovrić ◽  
Dražen Cvitanić ◽  
Deana Breški
Keyword(s):  
Field Survey ◽  
Evaluation Model ◽  
Practical Method ◽  
Flow Speed ◽  
Free Flow ◽  
Rural Highways ◽  
Speed Flow ◽  
Free Flow Speed ◽  
Flow Diagrams ◽  
Analysis Models

Free flow speed is used as a parameter in transportation planning and capacity analysis models, as well as speed-flow diagrams. Many of these models suggest estimating free flow speed according to measurements from similar highways, which is not a practical method for use in B&H. This paper first discusses problems with using these methodologies in conditions prevailing in B&H and then presents a free flow speed evaluation model developed from a comprehensive field survey conducted on nine homogeneous sections of state and regional roads.

High Speed Flow Through Wire Gauzes

1959 ◽  
Vol 63 (584) ◽  
pp. 474-475 ◽  
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
High Speed ◽  
Static Pressure ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Speed Flow ◽  
Wire Gauze ◽  
Flow Through

The Flow of Fluids through screens has been widely studied with particular importance being attached to the measurement of the pressure drop caused by a screen and its relation to the screen geometry and the flow conditions. The majority of the investigations have been carried out on wire gauze screens mounted in ducts with air passing through them, the static pressure being measured on either side of the gauze. Attempts have been made by Weighardt Annand and Grootenhuisto correlate the gauze geometry with the pressure drop and to enable the pressure loss over a given screen and with given flow conditions to be predicted.

scholarly journals Properties of Gas and Liquid Two Phase Swirling Flow in a Vertical Long Tube. 1st Report, Flow Pattern and Properties of Pressure Loss.

1994 ◽  
Vol 60 (578) ◽  
pp. 3345-3351 ◽  
Author(s):  
Kazuhisa Wakasugi ◽  
Tomohisa Nakanishi ◽  
Shinji Sakai ◽  
Kazunori Wakai ◽  
Isao Sumida
Keyword(s):  
Flow Pattern ◽  
Pressure Loss ◽  
Swirling Flow ◽  
Two Phase

Traffic Flow Modeling of Diverse Work Zone Activities

2018 ◽  
Vol 2672 (16) ◽  
pp. 23-34 ◽  
Author(s):  
Nipjyoti Bharadwaj ◽  
Praveen Edara ◽  
Carlos Sun ◽  
Henry Brown ◽  
Yohan Chang
Keyword(s):  
Flow Speed ◽  
Reduction Factor ◽  
Work Zone ◽  
Flow Curves ◽  
Work Activity ◽  
Speed Reduction ◽  
Work Activities ◽  
Speed Flow ◽  
Free Flow Speed ◽  
Reduction Factors

What effect does work activity type have on traffic conditions in a work zone? This question has still not been answered satisfactorily in practice. Without knowing the true effect a work activity has on traffic, practitioners are forced to make assumptions while scheduling work. This paper attempts to answer this question by studying the traffic flow characteristics, that is, traffic speed versus flow curves, capacity reduction factors, and free-flow speed reduction factors, for various activities related to construction and maintenance. The importance of the speed–flow curves and reduction factors for work zone planning is also stressed in the latest edition of the Transportation Research Board’s Highway Capacity Manual. This manual recommends capacity and speed reduction factors for work zones, yet does not include specific guidance for including the impact of work activities. Thre e traffic stream models, Gipps, Newell–Franklin, and Van Aerde, were calibrated using field data from St. Louis, Missouri. The Van Aerde model fitted the field data the best as compared to the other two models. Using the Van Aerde model-generated speed–flow curves, it was found that the capacity for bridge-related activities varied from 1,416 vehicles per hour per lane (vphpl) to 1,656 vphpl and for pavement-related activities from 1,120 vphpl to 1,728 vphpl. The capacity reduction factor for different work activities was found to be in the range 0.68 to 0.95, whereas the free-flow speed reduction factor was found to be in the range 0.78 to 1.0. The methodology proposed in this paper contributes toward the development of practitioner guidance and incorporation of work activity effects into traffic impact assessment tools.

An experimental investigation of the oil film distribution in an oil–gas cyclone separator

2016 ◽  
Vol 231 (1) ◽  
pp. 14-25 ◽  
Author(s):  
Lingzi Wang ◽  
Jianmei Feng ◽  
Shijing Xu ◽  
Xiang Gao ◽  
Xueyuan Peng
Keyword(s):  
Flow Pattern ◽  
Pressure Loss ◽  
Film Flow ◽  
Separation Efficiency ◽  
Flow Behavior ◽  
Outer Cylinder ◽  
Cylinder Wall ◽  
Cyclone Separator ◽  
Oil Film ◽  
Oil Gas

The film flow behavior in an oil–gas cyclone separator was experimentally studied to improve the separation efficiency in terms of the effect of the oil film on the cylinder wall. The oil film flow pattern was captured using a high-speed camera, and the cylinder wall was divided into seven regions to analyze according to the different oil film flow patterns. Along the cyclone cylinder height, the central part of the cylinder was the main flow area, in which droplet–wall collisions and oil film splashing were severe. Additionally, the oil film’s distribution characteristics under inlet velocities of 14.0, 16.0, and 18.0 m/s were compared, and the results showed that more splashing oil droplets were generated under higher inlet velocity. Moreover, changing the structure of the central channel and outer cylinder slightly changed the oil film’s area and flow pattern but exhibited a weak effect on the oil film thickness and re-entrainment. Then, an improved structure was proposed by adding a porous cylinder to the outer cyclone to avoid the generation of small splashing droplets from the oil film. The performance of the modified separator was measured in a real oil-injected compressor system, which demonstrated higher separation efficiency with no increase in static pressure loss. The separation efficiency increased by up to 2.7%, while the pressure loss decreased by up to 10%. Thus, the improved structure can improve the performance of oil–gas separators by changing the distribution and thickness of the oil film on the cylinder wall.

scholarly journals Pressure Loss in Ducts by Dissipative Splitter Silencers: Comparative Study of Standardized, Numerical and Experimental Results

2021 ◽  
Vol 11 (22) ◽  
pp. 10998
Author(s):  
Bartosz Chmielewski ◽  
Iván Herrero-Durá ◽  
Paweł Nieradka
Keyword(s):  
Finite Element Method ◽  
Comparative Study ◽  
Pressure Loss ◽  
Industrial Applications ◽  
Flow Speed ◽  
Point Of View ◽  
Experimental Measurements ◽  
Sound Waves ◽  
The Finite Element Method ◽  
Input Face

Dissipative splitter silencers are widely used in industry for the reduction of propagated sound waves in ducts. Even though these systems are effective from the acoustics point of view when they are properly designed, they also introduce a pressure loss in the system, due to the modification of the properties of the flow circulating inside the duct. This effect is not desired in some industrial applications, so it is necessary to be able to predict the pressure loss as precisely as possible to design silencers according to the needs. Nevertheless, the prediction made by standards are usually limited to given geometries or flow speed. In this work, we present a comparative study on the results obtained for the pressure loss by means of the standards ISO 14163 and VDI 1801-1, numerical simulations with the finite element method, and experimental measurements. Additionally, two different profile shapes and four input face velocities are tested in order to know the influence of these parameters in the variations of the flow and the accuracy of the prediction of the different methods.

Numerical Investigation of the Influence of Real World Blade Profile Variations on the Aerodynamic Performance of Transonic Nozzle Guide Vanes

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
R. Edwards ◽  
A. Asghar ◽  
R. Woodason ◽  
M. LaViolette ◽  
K. Goni Boulama ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Flow Pattern ◽  
Pressure Loss ◽  
Total Pressure ◽  
Aerodynamic Performance ◽  
Guide Vanes ◽  
Trailing Edges ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

This paper addresses the issue of aerodynamic consequences of small variations in airfoil profile. A numerical comparison of flow field and cascade pressure losses for two representative repaired profiles and a reference new vane were made. Coordinates for the three airfoil profiles were obtained from the nozzle guide vanes of refurbished turboshaft engines using 3D optical scanning and digital modeling. The repaired profiles showed differences in geometry in comparison with the new vane, particularly near the leading and trailing edges. A numerical simulation was conducted using a commercial CFD code, which uses the finite volume approach for solving the governing equations. The computational predictions of the aerodynamic performance were compared with experimental results obtained from a cascade consisting of blades with the same airfoil profiles. The CFD analysis was performed for the cascade at subsonic inlet and transonic exit conditions. Boundary layer growth, wake formation, and shock boundary layer interactions were observed in the two-dimensional computations. The flow field showed the presence of shock waves downstream of the passage throat and near the trailing edges of the blades. A conspicuous change in flow pattern due to subtle variation in airfoil profile was observed. The calculated flow field was compared with the flow pattern visualized in the experimental test rig using the schlieren method. The total pressure calculation for the cascade exit showed an increase in pressure loss for one of the off-design profiles. The pressure loss calculations were also compared with the multihole total pressure probe measurement in the transonic cascade rig.

Research on Relationships among Three Parameters in Short-Term Traffic Flow Forecasting

2011 ◽  
Vol 130-134 ◽  
pp. 2072-2076
Author(s):  
Xin Ping Xiao ◽  
Yi Chen Hu ◽  
Huan Guo
Keyword(s):  
Traffic Flow ◽  
Statistical Correlation ◽  
Flow Speed ◽  
Short Term ◽  
Flow Parameters ◽  
Speed Flow ◽  
Basic Parameters ◽  
Binary Linear Regression ◽  
Time Changes ◽  
Grey Relational

This paper expects to get the real-time changes of traffic flow by researching the relationships among the three basic parameters flow, speed and occupancy. we firstly carries out the statistical correlation analysis and grey relational analysis to study the connection between the traffic flow parameters flow and speed, flow and occupancy to get a conclusion that there doesn’t exist a significant linear relationship between neither of the comparisons, and the influence of speed on the flow is a little bigger than that of occupancy. Then we try to establish the binary linear regression model without the intercept and GM (0,3) model to do the data fitting, the final simulation results illustrate that the two methods has effects in some extent, also explain the complexity of traffic flow.

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