Longitudinal Mixing of Fluids Flowing in Circular Pipes

1958 ◽  
Vol 50 (3) ◽  
pp. 343-346 ◽  
Author(s):  
Octave Levenspiel
Keyword(s):  
Circular Pipes ◽  
Longitudinal Mixing

Longitudinal mixing in packed beds

1960 ◽  
Vol 12 (1) ◽  
pp. 20-34 ◽  
Author(s):  
E.J. Cairns ◽  
J.M. Prausnitz
Keyword(s):  
Packed Beds ◽  
Longitudinal Mixing

Graphed equilibrium parameters of channels formed in sediment

1980 ◽  
Vol 7 (1) ◽  
pp. 93-104 ◽  
Author(s):  
A.W. Peterson ◽  
T. Blench
Keyword(s):  
Subject Matter ◽  
Three Dimensional ◽  
Numerical Data ◽  
Reference List ◽  
Laboratory Measurements ◽  
Practical Applications ◽  
Circular Pipes ◽  
The Subject ◽  
Specialized Mathematics ◽  
Major Reference

This paper, for river engineers and their environmental counterparts, presents and explains the origin and potential of four-dimensional charts that smooth most of the world's numerical data obtained from the equilibrium dimensions of sand rivers, gravel rivers, and laboratory flumes. These charts aim to provide a practical service comparable with that provided by factual plots on the comprehensive classic three-dimensional Stanton friction-factor diagram for circular pipes and clean Newtonian fluid. In the river problems, especially, the existence of different phases (whose transitions are not susceptible to formulation), the inadequacies of textbook theories even for simple phases, and the unavoidable imperfections of both field and laboratory measurements combine to prevent responsible design. The remedy is a graphing of total information backed by references from which its reliability and practicability can be assessed.The references have been chosen to contain principal information in the forms of: (i) usable photos, graphs, and tables; (ii) explanations free from specialized mathematics and speculative arguments; and (iii) papers with discussions, authors' replies, and further useful references (since a major reference list would be too long for this paper). Because condensation has had to be extreme the authors will be glad to attempt answers to discussions and questions on the subject matter, its practical applications, and its implications in teaching and research.

Enhanced Longitudinal Mixing in a Lake Caused by Inflow-Induced Circulation

1985 ◽  
Vol 21 (2) ◽  
pp. 221-228
Author(s):  
Francis J. Ferrandino ◽  
Donald E. Aylor
Keyword(s):  
Longitudinal Mixing

Discussion of “Longitudinal Mixing in Natural Streams”

1968 ◽  
Vol 94 (3) ◽  
pp. 566-571
Author(s):  
Hugo B. Fischer ◽  
Nobuhiro Yotsukura
Keyword(s):  
Natural Streams ◽  
Longitudinal Mixing

Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion and Heat Transfer Via CFD and Experimental Work

2021 ◽  
Author(s):  
Ronald E. Vieira ◽  
Thiana A. Sedrez ◽  
Siamack A. Shirazi ◽  
Gabriel Silva
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Experimental Work ◽  
Heat Exchangers ◽  
Flow Patterns ◽  
Cfd Simulations ◽  
Liquid Distribution ◽  
Circular Pipes ◽  
Sand Erosion ◽  
Sand Flow

Abstract Air-water two-phase flow in circular pipes has been studied by many investigators. However, investigations of multiphase flow in non-circular pipes are still very rare. Triangular pipes have found a number of applications, such as multiphase flow conditioning, erosion mitigation in elbows, compact heat exchanges, solar heat collectors, and electronic cooling systems. This work presents a survey of air-water and air-water-sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Firstly, twenty-three experiments were performed for horizontal air-water flow. Detailed videos and slug frequency measurements were collected through circular and triangular clear pipes to identify flow patterns and create a database for these pipe configurations. The effect of corners of the triangular pipe on the liquid distribution was investigated using two different orientations of triangular pipe: apex upward and downward and results of triangular pipes were compared to round tubes. Secondly, ultrasonic wall thickness erosion measurements, paint removal studies, and CFD simulations were carried out to investigate the erosion patterns and magnitudes for liquid-sand and liquid-gas-sand flows in circular and triangular elbows with the same radius of curvature and cross-sectional area. Thirdly, heat transfer rates for liquid flows were also simulated for both circular and triangular pipe cross-sections. Although similar flow patterns are observed in circular and triangular pipe configurations, the orientation of the triangular pipes seems to have an effect on the liquid distribution and slug frequency. For higher liquid rates, slug frequencies are consistently lower in the triangular pipe as compared to the circular pipe. Similarly, the triangular elbow offers better flow behavior as compared to circular elbows when investigated numerically with similar flow rates for erosion patterns for both liquid-sand flow and liquid-gas-sand flows. Experimental and CFD results show that erosion in the circular elbow is about three times larger than in the triangular elbow. Paint studies results validated erosion patterns and their relations with particle impacts. Finally, heat transfer to/from triangular pipes is shown to be more efficient than in circular pipes, making them attractive for compact heat exchangers and heat collectors. This paper represents a novel experimental work and CFD simulations to examine the effects of pipe geometries on multiphase flow in pipes with several practical applications. The present results will help to determine the efficiency of utilizing triangular pipes as compared to circular pipes for several important applications and field operations such as reducing slug frequencies of multiphase flow in pipes, and reducing solid particle erosion of elbows, and also increasing the efficiency of heat exchangers.

The effect of the roller profile oncave-in defect in reshaping processby considering nonlinear combine strain hardening

2021 ◽  
pp. 095440542110368
Author(s):  
Siamak Mazdak ◽  
Hassan Moslemi Naeni ◽  
Mohammad Reza Sheykholeslami ◽  
Manabo Kiuchi ◽  
Hesam Validi
Keyword(s):  
Numerical Study ◽  
Contact Model ◽  
Slab Method ◽  
Incremental Method ◽  
Circular Pipes ◽  
Meaningful Relationship ◽  
Numerical Software ◽  
Combined Hardening ◽  
The Common ◽  
Roller Profile

The reshaping process of pipes is an important method in producing non-circular pipes. Desired profile products are produced by passing round pipe through the rotating rollers. Cave-in defect is one of the common defects in the reshaping process. Roller design issues can decrease this kind of defect. In this paper, a method based on the slab method and the incremental plasticity has been presented to the numerical study of a 2D reshaping process. For investigating the Cave-in defect, the contact model has been developed. The concept of element elongation has been introduced to increase the accuracy of the contact model. Based on the presented method, numerical software has been developed to simulate the 2D reshaping process. Elastic-plastic equations for this subject have been driven based on the incremental method, J yielding criterion, and non-linear combined hardening. The effects of the radius of the roller profile on cave-in defects have been investigated by using the presented software (DARF). A set of experiments has been conducted in a forming station to verify the results. Results show that the presented model has higher accuracy than the Abaqus commercial software in predicting the cave-in defect. Based on the results of the model, the local increase of yielding stress directly affects the cave-in defect. Also, a meaningful relationship between the radius of the roller and the amount of the cave-in has been observed.

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