Computer program gives blade-to-blade solution of the two-dimensional, subsonic, compressible, nonviscous flow problem for a circular or straight infinite cascade of tandem or slotted turbomachine blades. The method of solution is based on the stream function using iterative solution of nonlinear finite-difference equations

Katsanis, T.

Mcnally, W. D.

English

NASA Technical Reports Server

July 1969	 Brief 69-10219 
.
	
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information Springfield, Virginia 22151. 
FORTRAN IV Program Calculates Velocities and Streamlines in a

Tandem Blade Turbomachine 
The problem: 
Efforts are being made to design compressors and 
turbines with smaller diameters, fewer stages, and 
fewer blades per stage. All these factors tend to in-
crease diffusion. Therefore, it is desired to design 
blades with high diffusion, and at the same time avoid 
flow separation. Two concepts for accomplishing this 
are the tandem blade and the slotted blade. However, 
it is necessary to have a method of calculating the 
velocity distribution on the surface of such blades; 
this computer program provides an easy method. 
The solution: 
A computer program which gives the blade-to-
blade solution of the two-dimensional, subsonic, 
compressible (or incompressible), nonviscous flow 
problem for a circular or straight infinite cascade of 
tandem or slotted turbomachine blades. The blades 
may be fixed or rotating. The flow may be axial, radial, 
or mixed. 
How it's done: 
The method of solution is based on the stream 
function using an iterative solution of nonlinear finite-
difference equations. These equations are solved using 
two major levels of iteration. The inner iteration con-
sists of the solution of simultaneous linear equations 
by successive overrelaxation, using an estimated opti-
mum overrelaxation factor. The outer iteration then 
changes the coefficients of the simultaneous equations 
to correct for compressibility. 
The program input consists of the basic blade 
geometry, the meridional stream channel coordinates, 
fluid stagnation conditions, weight flow and flow split 
through the slot, and inlet and outlet flow angles. The 
output includes blade surface velocities, velocity 
magnitude and direction' throughout the passage, and 
the streamline coordinates. 
Notes: 
I. This program should be of interest to engineers 
and designers of compressors and turbines. 
2. The program is written in FORTRAN IV for use 
on the IBM 7094 11/7044 DCS. 
3. Inquiries should be made to: 
COSMIC 
Computer Center 
University of Georgia 
Athens, Georgia 30601 
Reference: B69-10219 
Patent status: 
No patent action is contemplated by NASA. 
Source: Theodore Katsanis and William D. McNally 
Lewis Research Center 
(LEW- 10743) 
Category 06 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000219 2020-03-16T17:40:54+00:00Z


FORTRAN 4 program calculates velocities and streamlines in a tandem blade turbomachine

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