NASA Technical Reports Server (NTRS) 20030099650: Easier Analysis With Rocket Science

2 Pages·0.04 MB·English

by  NASA Technical Reports Server (NTRS)

Easier Analysis With Rocket Science
A
nalyzing rocket engines is one of Marshall Space Subroutine module, making it possible to develop spe-
Flight Center’s specialties. When Marshall engi- cific applications of the code for various disciplines and
neers lacked a software program flexible enough customize those applications as needed. As a result,
to meet their needs for analyzing rocket engine fluid GFSSP has a wide variety of commercial applications
flow, they overcame the challenge by inventing the in industries that require flow predictions in complex
Generalized Fluid System Simulation Program (GFSSP), flow circuits.
which was named the co-winner of the NASASoftware Concepts NREC, Inc., of White River Junction,
of the Year award in 2001. Vermont, incorporated GFSSP into its commercially
Most rocket analysis tools are either engine or tur- available Cooled Turbine Airfoil Agile Design System
bopump specific, and some can only analyze one specif- (CTAADS). Specializing in all aspects of turbomachin-
ic engine or perform one part of a test. Consequently, ery with applications ranging from aircraft engines to
Marshall engineers often use multiple software tools and industrial pumps, the company developed the product in
modules to complete their work. Frequently, however, conjunction with Harvard Thermal, Inc., of Harvard,
the different tools cannot communicate, causing road- Massachusetts, to significantly reduce the total time and
blocks during analysis. The engineers needed a software cost for designing cooled turbine airfoils.
program that could plug into virtually any scenario and Gas turbines used for aircraft propulsion must operate
be operated with minimal training and computer- at high temperatures for thermal efficiency and power
processing power. As a result, the Marshall development input. However, these extreme temperatures can cause
team for GFSSPfocused on flexibility when developing thermal stresses within the turbine blade materials,
the base code for the new software program. necessitating that the blades be cooled by air extracted
NASA’s GFSSP has been extensively verified by from the engine’s compressor for safe and efficient oper-
comparing its predictions with test data. The software ation. Since thermal efficiency decreases as a result of
uses a highly intuitive graphical user interface that this extraction, engineers need to understand and opti-
allows engineers to construct very complex models in a mize the cooling technique, operating conditions, and
very short time and allows users to model and view the turbine blade geometry.
results with a click of a mouse. With changing require- An increased understanding of the detailed hot-gas-
ments and needs, the software has evolved to GFSSP flow physics within the turbine itself is necessary to
version 3.0. This latest version contains a User design a system that most efficiently cools the turbine
Turbine blades must be properly
cooled for safe and efficient oper-
ation. This first-stage turbine
blade has its cooling holes and
drilled trailing edge highlighted.
y
g
o
l
o
n
h
c
e
T

r
e
t
u
p
m
o
C
58 S P I N O F F 2 0 0 3
blades. Since blade life can be reduced by half if the tem- The internal cooling airflow module gives users max- C
perature prediction is off by only 50 °F, it is crucial to imum flexibility in defining the fluid flow network. o
m
accurately predict the local heat-transfer coefficient, as Users can control how many sections are needed to
p
well as the local blade temperature, in order to prevent define each cooling passage. The fluid network solver is u
local hot spots and increase turbine blade life. capable of producing turbine airfoil cooling passage air- t
e
CTAADS assists users in need of this information flow calculations requiring compressible flow with fric- r

by providing a systematic, logical, and rapid three- tion, heat addition, and area change; pumping due to T
e
dimensional (3-D) modeling approach to cooling- blade rotation; and choked flow. Concepts NREC also c
h
system design for cooled axial turbine vanes and blades. added numerous resistance options specific to turbine
n
The product is a fully integrated suite of independent cooling to GFSSP. All options have default correlations o
l
software modules that supports the rapid generation for total pressure loss and heat transfer coefficients. o
of airfoil cooling-passage geometry and performs com- Outside of the success Concepts NREC has found g
y
plete 3-D thermal analysis. with utilizing GFSSP, other possible commercial appli-
CTAADS’s internal cooling airflow module, which cations for the versatile software program include heat-
generates and solves a one-dimensional fluid flow net- ing ventilation and air conditioning systems, chemical
work representing the entire cooling configuration, is processing, gas processing, power plants, hydraulic con-
built upon GFSSP. Users can construct the fluid flow trol circuits, and various types of fluid distribution sys-
network with a Concepts NREC-developed graphical tems. Best of all, GFSSPis easy to learn, despite its roots
user interface. The network is then transformed into a in rocket science. According to Marshall’s GFSSPteam
customized input file for GFSSP, and the fluid network leader Alok Majumdar, “A goal of ours was to make
solver is a significantly modified and customized version GFSSPso that an undergraduate engineering student can
of GFSSP. quickly become proficient with the software.”
The Cooled Turbine Airfoil Agile Design System provides a sys-
tematic, logical, and rapid three-dimensional modeling approach
for designing cooled turbine airfoils.
S P I N O F F 2 0 0 3 59