Theoretical model of gravitational perturbation of current collector axisymmetric flow field

1990 ◽  
Vol 67 (10) ◽  
pp. 6099-6108 ◽  
Author(s):  
John S. Walker ◽  
Samuel H. Brown ◽  
Neal A. Sondergaard
1990 ◽  
Author(s):  
A. Kirschner ◽  
H. Stoff

A cascade design-method is presented which complements the meridional through-flow design procedure of turbomachines. Starting from an axisymmetric flow field and the streamline geometry in the meridional plane this simple method produces a solution for the quasi three-dimensional flow field and the blade-element geometry on corresponding stream surfaces. In addition, it provides intra-blade data on loss and turning required for a consistent design and a convenient means of optimizing blade loading. The purpose of this paper is to describe the theoretical basis of the method and to illustrate its application in the design of transonic compressors.


2020 ◽  
Vol 7 (3) ◽  
pp. 597-610 ◽  
Author(s):  
Tian Zhang ◽  
Deji Jing ◽  
Shaocheng Ge ◽  
Jiren Wang ◽  
Xiangxi Meng ◽  
...  

Abstract To simulate the transonic atomization jet process in Laval nozzles, to test the law of droplet atomization and distribution, to find a method of supersonic atomization for dust-removing nozzles, and to improve nozzle efficiency, the finite element method has been used in this study based on the COMSOL computational fluid dynamics module. The study results showed that the process cannot be realized alone under the two-dimensional axisymmetric, three-dimensional and three-dimensional symmetric models, but it can be calculated with the transformation dimension method, which uses the parameter equations generated from the two-dimensional axisymmetric flow field data of the three-dimensional model. The visualization of this complex process, which is difficult to measure and analyze experimentally, was realized in this study. The physical process, macro phenomena and particle distribution of supersonic atomization are analyzed in combination with this simulation. The rationality of the simulation was verified by experiments. A new method for the study of the atomization process and the exploration of its mechanism in a compressible transonic speed flow field based on the Laval nozzle has been provided, and a numerical platform for the study of supersonic atomization dust removal has been established.


2008 ◽  
Vol 22 (1) ◽  
pp. 166-170 ◽  
Author(s):  
Byeung Jun Lim ◽  
Seung Jin Song

Author(s):  
Yuki Toda ◽  
Masataka Morimatsu ◽  
Yu Nishio ◽  
Takanobu Ogawa

Abstract A tube-type gas burner consists of a straight tube with a slit along it and discharges an air-gas mixture through the slit to produce a flame. The flow velocity from the slit depends on the pressure in the tube and the pressure loss at the slit, and it varies in the longitudinal direction of the tube. The resulting uneven flame degrades the quality of the burner. In this study, we develop a one-dimensional theoretical model of the flow in a tube with a slit. To validate the result of the theoretical model, we also conduct experiments and numerical simulations for the same flow field. We applied this theoretical model to a flow in a tube, 1 m length, 40 mm in diameter, with a slit 2.5 mm wide. The end of the tube is closed. We also discuss the effect of the length of the burner on the unevenness.


2009 ◽  
Vol 60-61 ◽  
pp. 260-264
Author(s):  
Bo Zhang ◽  
Yu Feng Zhang ◽  
Xiao Wei Liu ◽  
Peng Zhang

Based on the visualization technology, we investigated experimentally the effect of different flow patterns on anode fluid behaviors of the μDMFC (Micro Direct Methanol Fuel Cell) with a transparent material under the same condition. Stainless steel mesh was utilized as the current collector which was distinct from the carbon cloth or carbon paper. Four dissimilar flow patterns were developed and tested. The observation of the effect of different flow patterns revealed that movements of dilute methanol solutions and CO2 gas bubbles in the dot and parallel flow fields represented more difficult, which could result in a decline of the μDMFC performance. The study also showed that a channel blocking in the single-serpentine flow field would be extremely terrible which could lead to a fuels leaking of the μDMFC, meanwhile the liquid-gas flow was more fluent and stable in a double-serpentine flow field. Therefore, due to its advantages, a double-serpentine flow pattern is more suitable for the μDMFC application compared with the other flow patterns.


1989 ◽  
Vol 209 ◽  
pp. 617-637 ◽  
Author(s):  
S. T. Vuong ◽  
S. S. Sadhal

The fluid dynamics associated with a compound drop consisting of a vapour bubble, partly surrounded by its own liquid in another immiscible liquid is considered. The fluid motion is analysed in the limit of Stokes flow and at the same time the surface tension forces are considered to be large enough to allow the interfaces to have uniform curvature. The flow field consists of translation and growth that can arise from change of phase.An exact analytical solution for the axisymmetric flow field is obtained. The important results of physical interest are the drag force and the flow behaviour. In the case without growth, the drag force lies between the bubble and the solid-sphere limits for a sphere of the same volume as the total liquid and vapour dispersed phase. The maximum drag force is observed when the liquid and vapour volumes are nearly the same. This is the effect of weak circulation due to the smaller available space as compared with a spherical drop. With growth this effect appears to be enhanced. The flow streamlines exhibit secondary vortices in the dispersed phase when there is growth. The velocity field and the drag results here are applied to the heat transfer problem for the compound drop in Part 2 of this two-part series.


RSC Advances ◽  
2014 ◽  
Vol 4 (102) ◽  
pp. 58888-58894 ◽  
Author(s):  
L. Zielke ◽  
A. Fallisch ◽  
N. Paust ◽  
R. Zengerle ◽  
S. Thiele

In this paper we consider a numerically constructed solution concerning the steady nonlinear flow field generated by a point force of magnitude F 0 in an incompressible fluid bounded by a plane wall. The force is applied at a fixed distance from the wall and is perpendicular to it. The streamlines in a meridian section form closed loops which nest at a stagnation point and it is found that as F 0 increases this stagnation point is displaced towards or away from the wall depending on whether the force is pointing towards or away from it. It is also found that as F 0 increases the total volume flux per unit force decreases when the force is pointing towards the wall and increases when the force is pointing in the opposite direction. For instance when F 0 is 150 v 2 ρ , where v denotes the coefficient of kinematic viscosity and ρ the fluid density, the total volume flux for the case where the force points away from the wall is several times that for the case where the force points towards the wall.


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