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jcchin edited this page Oct 10, 2014 · 14 revisions

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Welcome to the TTECTrA_dev Wiki!

Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA)

Designed to provide an estimate of the closed-loop transient performance/capability of a conceptual engine design at a specified flight condition

Jeffrey Csank, Jonathan Seidel, Jeffrey Chin - NASA Glenn Research Center

Alicia Zinnecker - N&R Engineering

Georgia Institute of Technology

(This wiki is currently very outdated, last update 11/6/2013)

#Wiki Table of Contents

This repository contains three main folders, the first two are transient NPSS engine models for a notional 150 and 300 passenger aircraft. These models were original supplied by Georgia Tech and modified to run either independently, or with Matlab and Simulink. The third folder contains the code to run NPSS within Matlab and Simulink.

  1. Code Repository File Organization (How files are organized in this repository)
  2. Notes/Modifications to NPSS from Georgia Tech (These are modifications made to the model based on email conversations and powerpoints from GT)
  3. Notes/Modifications to NPSS to extended Matlab/Simulink capability (These are modifications made to the model to facilitate file wrapping and so various run parameters can be controlled within the Matlab environment)
  4. Description of embedded NPSS Simulink Model (This provides an in-depth description and operation instructions for running NPSS from within Matlab and Simulink)
  5. Version Change Log
  6. List of functionality tests

To download the latest source code, go to

Downloads -> Branches -> .zip

Or if your using git: To clone the main repo and wiki:

$ git clone https://github.com/jcchin/TTECTrA_dev.git

To clone just the wiki:

$ git clone https://github.com/jcchin/TTECTrA_dev.wiki.git

Wiki pages are normal files, with the .md extension. You can edit them locally, as well as creating new ones.

#Matlab Quick Start

  1. From the Matlab folder, edit
npss_location = ''; %path location of the NPSS executable
ModelDir = ''; %path location of this particular engine model

with the appropriate paths

  1. Run TTECTrA_auto.m

#NPSS Quick Start

  1. Download the repository
  2. From the command window, navigate into the folder 150PAX or 300PAX
  3. Update "run_npss.bat" to the appropriate path pointing to your NPSS installation. (In my case the path is, C:\Program Files (x86)\NPSS.V165C) There can be no spaces in the path, so Program Files (x86) is rewritten as "Progra~2" meaning its the second folder starting with "Progra..."
    set NPSS_TOP=C:\Progra~2\NPSS.V165C

4. Run the following command from inside 300PAX folder (or similarly in the 150PAX folder) using any of the -DNAME flags listed below

    run_npss.bat 150PAX_Sfunction.run -DFLTENV

5. That's it! For more help see Jeff (215-433-2026, jeffrey.c.chin@nasa.gov)

Running from the command line

Each case file can be run from the command line using the following syntax

run example.run –DFLTENV –DEXAMPLEIFDEFNAME

Example commands for the provided case files are as follows

run CMAPSS40K.run –DFLTENV –DACCELSCHEDULE
run CMAPSS40K.run –DFLTENV –DMAXLIMITSCHEDULE
run CMAPSS40K.run –DFLTENV –DMINLIMITSCHEDULE
run CMAPSS40K.run –DFLTENV –DPOWERMANAGEMENT

Changes to CMAPSS40K folder

Following files changed in CMAPSS40K for integrating linear model generator

  1. CMAPSS40K.run – changes to printing to the screen
  2. High_BPR_CMAPSS40K.mdl – introduced new variable EPR for linear model generation and linear model generation script
  3. Solver_setup.fnc – added constraints and solver settings for stall and solver stability for NASA provided CMAPSS40K transients

Following files are additional

  1. linear_model_CMAPSS40K.run – calls linear model generation functions at several flight conditions
  2. Linear_model.fnc – functions for creating linear model output stream and its format, setting up solver for linear model generation, and returning solver back to simulation settings

NPSS File Organization

150 Pax

  • input - Contains input variables to intialize the engine, these can be generated by Matlab, or directly within NPSS.
  • maps - Contains turbomachinery performance maps
  • output - Contains all code output
  • run - Contains NPSS run files
  • src - Contains all model files, and solver setup functions.
  • viewers - Contains all viewer files, which create the output code.
  • .gitignore - Contains rules for files to be ignored by version control (git)
  • run_npss.bat - Working setup batch file

Tips for editing this wiki

This wiki uses the Markdown syntax. The wiki itself is actually a git repository (submodule within the ttectra_dev repo), which means you can clone it, edit it locally/offline, add images or any other file type, and push it back to us. It will be live immediately.

Syntax highlighting

You can highlight snippets of text using the Pygments library.

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def wiki_rocks(text):
    formatter = lambda t: "funky"+t
    return formatter(text)
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