Numerical Inviscid Flow Analysis of the GAMM Francis Runner

1993 ◽  
pp. 71-76
Author(s):  
J. T. Billdal ◽  
Ø. Jacobsen ◽  
K. Bratsberg ◽  
H. I. Andersson ◽  
H. Brekke
Keyword(s):  
Flow Analysis ◽  
Inviscid Flow

Optimization of the Three-Dimensional Flow Path in the Scroll-Nozzle System of a Radial Inflow Turbine

1984 ◽  
Vol 106 (2) ◽  
pp. 511-515 ◽  
Author(s):  
E. A. Baskharone
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Three Dimensional Flow ◽  
Multiply Connected ◽  
Dimensional Flow ◽  
Nozzle Configuration ◽  
Flow Domain ◽  
Radial Inflow Turbine ◽  
Compressibility Effects

A three-dimensional inviscid flow analysis in the combined scroll-nozzle system of a radial inflow turbine is presented. The coupling of the two turbine components leads to a geometrically complicated, multiply-connected flow domain. Nevertheless, this coupling accounts for the mutual effects of both elements on the three-dimensional flow pattern throughout the entire system. Compressibility effects are treated for an accurate prediction of the nozzle performance. Different geometrical configurations of both the scroll passage and the nozzle region are investigated for optimum performance. The results corresponding to a sample scroll-nozzle configuration are verified by experimental measurements.

Three-dimensional inviscid flow analysis of turbofan forced mixers

1985 ◽  
Author(s):  
T. BARBER ◽  
G. MULLER ◽  
S. RAMSAY ◽  
E. MURMAN
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Inviscid Flow

scholarly journals Numerical Simulation of Cascade Flow: Vortex Element Method for Inviscid Flow Analysis and Axial Turbine Blade Design

2021 ◽  
Vol 85 (2) ◽  
pp. 14-23
Author(s):  
Nono Suprayetno ◽  
Priyono Sutikno ◽  
Nathanael P. Tandian ◽  
Firman Hartono
Keyword(s):  
Best Practice ◽  
Lift Coefficient ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Turbine Rotor ◽  
Design Stage ◽  
Outer Diameter ◽  
Axial Turbine ◽  
Cascade Flow

This study aims to design an axial turbine rotor blade and predict the turbine performance at preliminary design stage. Quasi three dimensional method was applied to design including blade to blade flow analysis. The blade profile uses a NACA 0015 airfoil by varying the profile thickness from hub to tip. The profile is divided into eleven segments which has different parameters. The profile was analysed using blade to blade flow/cascade flow analysis called vortex panel method to obtain lift coefficient. The analysis of cascade flow was performed in potential flow and prediction of turbine perfomance is carried out involving common best practice to give drag effect on the blade. The design of the turbine was applied on three different rotors, which also have a different discharge, head, and design rotation. The outer diameter of turbine 1 is 0.65 m, while turbine 2 and turbine 3 have an outer diameter of 0,60 m. The calculation result show that the efficiency of turbines 1, 2, and 3 were 88,32%, 89,67%, and 89,04%, respectively.

Subsonic Propulsion System Installation Analysis and Optimization

1991 ◽  
Author(s):  
J. L. Colehour ◽  
B. W. Farquhar ◽  
J. E. Gengler ◽  
T. A. Reyhner
Keyword(s):  
Potential Flow ◽  
Low Cost ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Inviscid Flow ◽  
Wave Drag ◽  
Propulsion System ◽  
Design Development ◽  
Improved Performance

Computational fluid dynamics (CFD) now allows analysis of propulsion system installations on subsonic transports to an extent that many configuration decisions can be made without testing. The methods discussed here utilize low-cost potential flow methods to predict inviscid flow characteristics and utility methods to model geometry, generate computational mesh, estimate wave drag, and perturb geometry in ways that promise improved performance. Jet plume effects are included in the potential flow analysis by means of a plume simulation method. Wave drag predictions yield levels of drag that are consistent with wind tunnel results, and, through contour optimization, wave drag for a trial propulsion installation geometry was reduced by about 50%. We conclude that through the use of methods such as these, many propulsion system installation design decisions can be made by analysis relatively quickly, which should lead to reduced design development time and cost.

Interaction of rarefaction waves with area reductions in ducts

1983 ◽  
Vol 137 ◽  
pp. 285-305 ◽  
Author(s):  
J. J. Gottlieb ◽  
O. Igra
Keyword(s):  
Steady Flow ◽  
Rarefaction Wave ◽  
Gas Flow ◽  
Flow Analysis ◽  
Inviscid Flow ◽  
Rarefaction Waves ◽  
Area Reduction ◽  
Random Choice Method ◽  
Wave Patterns ◽  
The One

The interaction of a rarefaction wave with a gradual monotonic area reduction of finite length in a duct, which produces transmitted and reflected rarefaction waves and other possible rarefaction and shock waves, was studied both analytically and numerically. A quasi-steady flow analysis which is analytical for an inviscid flow of a perfect gas was used first to determine the domains of and boundaries between four different wave patterns that occur at late times, after all local transient disturbances from the interaction process have subsided. These boundaries and the final constant strengths of the transmitted, reflected and other waves are shown as a function of both the incident rarefaction-wave strength and area-reduction ratio, for the case of diatomic gases and air with a specific-heat ratio of 7/5. The random-choice method was then used to solve numerically the conservation equations governing the one-dimensional non-stationary gas flow for many different combinations of rarefaction-wave strengths and area-reduction ratios. These numerical results show clearly how the transmitted, reflected and other waves develop and evolve with time, until they eventually attain constant strengths, in agreement with quasi-steady flow predictions for the asymptotic wave patterns. Note that in all of this work the gas in the area reduction is initially at rest.

scholarly journals A Rapid Aerodynamic Loading Procedure for Centrifugal Impeller Design

1994 ◽  
Author(s):  
J. H. G. Howard ◽  
Colin Osborne ◽  
David Japikse
Keyword(s):  
Industrial Design ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Design Procedure ◽  
Inviscid Flow ◽  
Centrifugal Impeller ◽  
Zone Model ◽  
Geometry Design ◽  
Loading Method ◽  
Rapid Loading

A crucial aspect of the design process for centrifugal impellers is the establishment of specific blade shapes. A rapid inviscid flow analysis procedure was developed for incorporation within a geometry manipulation code. Using a single streamtube model, a single-pass computation technique was generated. A two-zone model ensures that key features of the passage flow physics are incorporated. Several examples of industrial design problems are employed to demonstrate the capabilities of the rapid loading method and its use in a geometry design procedure (used by some 20 industrial design groups worldwide). Comparisons with a quasi-three-dimensional method are included. The rapid loading method is most accurate when the meridional stream paths have similar shapes to those for the hub and shroud contours. The technique is useful within a geometry generation program since rapid aerodynamic screening of candidate configurations is allowed with sufficient accuracy to avoid the need for quasi-three-dimensional approaches. If required, the final design may be analyzed using three-dimensional viscous flow calculation methods.

Influence of airfoil thickness on unsteady aerodynamic loads on pitching airfoils

2015 ◽  
Vol 774 ◽  
pp. 460-487 ◽  
Author(s):  
Valentina Motta ◽  
Alberto Guardone ◽  
Giuseppe Quaranta
Keyword(s):  
Flat Plate ◽  
Lift Coefficient ◽  
Finite Thickness ◽  
Flow Analysis ◽  
Unsteady Aerodynamics ◽  
Inviscid Flow ◽  
Hysteresis Curve ◽  
Normal Velocity ◽  
Airfoil Surface ◽  
Aerodynamic Loads

The influence of the airfoil thickness on aerodynamic loads is investigated numerically for harmonically pitching airfoils at low incidence, under the incompressible and inviscid flow approximation. Force coefficients obtained from finite-volume unsteady simulations of symmetrical 4-digit NACA airfoils are found to depart from the linear Theodorsen model of an oscillating flat plate. In particular, the value of the reduced frequency resulting in the inversion – from clockwise to counter-clockwise – of the lift/angle-of-attack hysteresis curve is found to increase with the airfoil thickness. Both the magnitude and direction of the velocity vector due to pitching over the airfoil surface differ from their flat-plate values. During the upstroke, namely nose-up rotation, phase, this results in a decrease (increase) of the normal velocity magnitude over the upper (lower) surface of the airfoil. The opposite occurs during the downstroke phase. This is confirmed by comparing the computed pressure distribution to the flat-plate linear Küssner model. Therefore, beyond the inversion frequency, the lift coefficient of a finite-thickness airfoil is higher during upstroke and lower during downstroke than its flat-plate counterpart. A similar dependence is also found for the quarter-chord moment coefficient. Accordingly, a modification to the classical Theodorsen model is proposed to take into account the effects of the airfoil thickness on unsteady loads. The new model is found to accurately predict the unsteady aerodynamics of a thick symmetric and a slightly cambered airfoil with a maximum thickness in the range 4–24 %. The limits of the present inviscid flow analysis are assessed by means of numerical simulation of high Reynolds number ($\mathit{Re}=10^{6}$) flows.

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