Three-dimensional potential flow through a rectilinear cascade of blades

1975 ◽  
Vol 44 (1) ◽  
pp. 27-41 ◽  
Author(s):  
A. F. de O. Falc�o
2001 ◽  
Vol 123 (2) ◽  
pp. 256-264 ◽  
Author(s):  
B. P. M. van Esch ◽  
N. P. Kruyt

The hydraulic performance of an industrial mixed-flow pump is analyzed using a three-dimensional potential flow model to compute the unsteady flow through the entire pump configuration. Subsequently, several additional models that use the potential flow results are employed to assess the losses. Computed head agrees well with experiments in the range 70 percent–130 percent BEP flow rate. Although the boundary layer displacement in the volute is substantial, its effect on global characteristics is negligible. Computations show that a truly unsteady analysis of the complete impeller and volute is necessary to compute even global performance characteristics; an analysis of an isolated impeller channel and volute with an averaging procedure at the interface is inadequate.


1993 ◽  
Vol 115 (2) ◽  
pp. 233-238 ◽  
Author(s):  
M. S. Greywall

An approach to compute three-dimensional flows using two stream functions is presented. The independent variables used are χ, a spatial coordinate, and ξ and η, values of stream functions along two sets of suitably chosen intersecting stream surfaces. The dependent variables used are the streamwise velocity, and two functions that describe the stream surfaces. Since the value of a stream function is constant along the solid boundaries, this choice of variables makes it easy to satisfy the boundary conditions. To illustrate the approach, computations of incompressible potential flow through a circular-to-rectangular transition duct are also presented.


1977 ◽  
Vol 99 (1) ◽  
pp. 167-175 ◽  
Author(s):  
R. Howells ◽  
B. Lakshminarayana

A relatively simple and rapid method for predicting the three-dimensional flow effects in axial flow turbomachinery was investigated. Although the two-dimensional cascade is a satisfactory approximation for the design and analysis of some types of turbo-machines, the flow through devices, such as propeller pumps and inducers, may deviate significantly. A three-dimensional lifting surface theory was used to predict the potential flow around blades, represented by line vortices and sources, spanning an annulus. A rotor was designed, built, and tested (with air as the test medium) for comparison with the theory. Static pressure distributions on a rotating blade were measured. The effect of blade dihedral on these pressures was also measured. Deviation from cascade predictions caused by the three-dimensional flow effects is found to be appreciable for propeller pumps. No theory was developed, but variation of the experimental blade pressure distributions caused by dihedral was found to be considerable.


2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).


2000 ◽  
Vol 124 (1) ◽  
pp. 140-146 ◽  
Author(s):  
V. Schramm ◽  
K. Willenborg ◽  
S. Kim ◽  
S. Wittig

This paper reports numerical predictions and measurements of the flow field in a stepped labyrinth seal. The theoretical work and the experimental investigations were successfully combined to gain a comprehensive understanding of the flow patterns existing in such elements. In order to identify the influence of the honeycomb structure, a smooth stator as well as a seal configuration with a honeycomb facing mounted on the stator wall were investigated. The seal geometry is representative of typical three-step labyrinth seals of modern aero engines. The flow field was predicted using a commercial finite volume code with the standard k-ε turbulence model. The computational grid includes the basic seal geometry as well as the three-dimensional honeycomb structures.


1960 ◽  
Vol 82 (4) ◽  
pp. 921-927 ◽  
Author(s):  
Friedrich O. Ringleb

The conditions for the equilibrium of two vortexes in a two-dimensional flow through a duct or diffuser are derived. Potential-flow considerations and a few basic results from viscous-flow theory are used for the discussion of the role of cusps as separation control and trapping devices for standing vortexes. The investigations are applied to cusp diffusers especially with regard to the wind tunnel of the James Forrestal Research Center of Princeton University.


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