scholarly journals Numerical Simulation in Steady Flow of Non-Newtonian Fluids in Pipes with Circular Cross-Section

Author(s):  
F.j. Galindo-rosales ◽  
F.j. Rubio-hernndez
2008 ◽  
Author(s):  
F. J. Galindo-Rosales ◽  
F. J. Rubio-Hernández ◽  
Albert Co ◽  
Gary L. Leal ◽  
Ralph H. Colby ◽  
...  

2012 ◽  
Vol 516-517 ◽  
pp. 917-920
Author(s):  
Xue Yao Wang ◽  
Xue Zhi Wu ◽  
Sheng Dian Wang ◽  
Xiang Xu ◽  
Yun Han Xiao

The flow character in riser is important for deep understanding the steady and high-efficient running of CFBs. In this paper, the 2D numerical simulation research for bench-scale circular cross-section riser based on EMMS methods is carried out. The solids’ transient moving profiles are captured. By analyzing the axial solids concentration profiles by simulation and experimental methods, the practicability of the EMMS model is verified.


2018 ◽  
Vol 180 ◽  
pp. 02093
Author(s):  
Smyk Emil ◽  
Mrozik Dariusz ◽  
Olszewski Łukasz ◽  
Peszyński Kazimierz

Determining of minor losses coefficient is very complicated problem. Analytical methods are often very difficult and experimental methods are very expensive and time-consuming. Consequently, the use of numerical methods seems to be a good solution, but there are no publications describing this issue. Therefore, the paper is describing the numerical method of determining the minor loss coefficient ξ on the example of elbows with circular cross-section.


2018 ◽  
Vol 8 (1) ◽  
pp. 322-328
Author(s):  
Moloshnyi Oleksandr ◽  
Szulc Przemyslaw

Abstract The paper concerns the analysis of the cavitation processes in the flow passages of the radial labyrinth pump. The object of the analysis contains the active (moving) and the passive (stationary) discs with straight channels trajectory and semi-circular cross-section. The conversion of the mechanical energy into hydraulic based on the exchange of the momentum between the liquid remaining in the moving and the stationary areas of the discs as well as on the centrifugal increase of the moment of momentum. The analysis of the cavitation processes was realized by the experimental research and the numerical simulation. In the article, the comparison of the cavitation characteristics was carried out. The numerical simulation had given similar results to the experimental one, the process of the cavitation was visualized. Furthermore, numerical investigations helped to describe the cavitation development. The results of the numerical research such as the distributions of the velocity, pressure and vapor volume fraction in the passages were presented. At first, cavitation starts on the back side and on the top of the wall between channels of the active disc. Further, the cavitation areas are growing along the axis of the channels. Eventually, they separation was observed and vortices of the vapour-gas mixture in the middle of the channels were formed. This phenomenon is so-called super cavitation vortices.


Author(s):  
Shiva P Pudasaini ◽  
Yongqi Wang ◽  
Kolumban Hutter

This paper presents a new model and discussions about the motion of avalanches from initiation to run-out over moderately curved and twisted channels of complicated topography and its numerical simulations. The model is a generalization of a well established and widely used depth-averaged avalanche model of Savage & Hutter and is published with all its details in Pudasaini & Hutter (Pudasaini & Hutter 2003 J. Fluid Mech. 495 , 193–208). The intention was to be able to describe the flow of a finite mass of snow, gravel, debris or mud, down a curved and twisted corrie of nearly arbitrary cross-sectional profile. The governing equations for the distribution of the avalanche thickness and the topography-parallel depth-averaged velocity components are a set of hyperbolic partial differential equations. They are solved for different topographic configurations, from simple to complex, by applying a high-resolution non-oscillatory central differencing scheme with total variation diminishing limiter. Here we apply the model to a channel with circular cross-section and helical talweg that merges into a horizontal channel which may or may not become flat in cross-section. We show that run-out position and geometry depend strongly on the curvature and twist of the talweg and cross-sectional geometry of the channel, and how the topography is shaped close to run-out zones.


2012 ◽  
Vol 7 (3) ◽  
pp. 155892501200700
Author(s):  
Xiaosong Liu ◽  
Fumei Wang

The models of polyethylene terephthalate (PET) non-circular cross-section (NCCS) fibers were established, and the characteristic parameters of non-circular cross-section fiber used in this numerical simulation were extracted. Furthermore, the differences of refracted light intensity ratio Irz and the direction of refracted light βt among circular, trilobal and quadri-lobal cross-section fibers were analyzed theoretically. The results show that the refracted light intensity ratios Irz of these fibers were in the range of 0.94~0.95. Both the trilobal and quadri-lobal cross-section fibers’ βt, which was the angle of refracted light to Y-axis, changed non-monotonically and much more intricately than that of circular cross-section ones. Moreover, according to the theory of geometrical optics, the effects of trilobal and quadri-lobal cross-section shapes on the changes of internal refracted light and transmitted light in fibers were also conducted. The results suggested that the refracted and transmitted light were changed more effectively in the quadri-lobal cross-section fiber. The results of the experiment show that the shielding properties of quadri-lobal cross-section filament fabrics were better than that of the counterparts with circular fibers, but the difference was limited or insignificant.


Author(s):  
R. S. Rivlin

In this paper, the general hydrodynamic theory of visco-inelastic, incompressible, non-Newtonian fluids, developed in a previous paper (l), is applied to the problem of the flow of such a fluid through a tube of circular cross-section. It is found that the absolute values of the normal stress components are no longer uniform over a cross-section of the tube normal to its axis, as in the case of Newtonian fluids obeying the laws of classical hydrodynamics.However, the pressure difference, between points at equal radii on two planes normal to the axis, is independent of the position of these points on the planes.


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