Rotor Dynamics Laboratory VTFAST Page

VT-FAST ver. 3.0
Virginia Tech - Front-end Automated Simulation of Turbomachinery

Date:

Program Capability:

Integrated PC-based computer programs for total solution to lateral rotating machinery dynamic analysis and design evaluation. The package consists of a user friendly front-end that can input and/or update a given rotor bearing system. The major rotor input front-end has on-line help screens to assist with parameter descriptions and requirements. Programs for analysis of fluid-film bearings, oil seals, turbulent seals, and gas labyrinth seals run independently but produce files of characteristics that can be imported into the rotor front-end. Analysis for undamped critical speeds, forced response, and stability evaluation of damped eigenvalues. The output of the response program can be plotted to screen, dumped to a laser printer, or dumped for import into a document file. An on-screen 3-D simulation of the forced response rotor mode shapes and the damped natural frequency mode shapes can give added understanding to the complex rotor behavior.

Method:

The rotor analysis programs may be selected from either a transfer matrix solution or a finite element solution for response and stability evaluation. The bearing programs are finite element based with an overall flow-heat balance evaluation to estimate operating film temperatures. Bearing analysis for multi-lobe, including pocket type fixed geometry bearings and also tilting pad bearings are solved by finite element based solutions that have been proven to be acceptable for turbomachinery analysis. The turbulent seal and gas labyrinth seal programs are based on bulk-flow type solutions with assumption of centered seal operation. The oil seal programs are based on a finite difference solution and include the evaluation of multi-ring operation with ring to ring loading options and an approximate thermal solution for evaluation of land temperatures and overall flow.

Limitations and Restrictions:

Rotor limited to 300 geometry stations with 120 major mass station computation. Up to 20 bearing and/or seal locations. Probe location and orientation for forced response analysis for up to 12 locations along the rotor. Extended memory required for the programs range from between 4 and 20 meg. The largest memory is required for the FEM Rotor Analysis Modules.

Documentation:

On-line help for the major modules. Manuals to specify the input formats are also available.

Input:

Data files in formatted form. The front-ends automate the generation and running of the response and stability. Front-ends for the bearing and seal codes are also provided, but are run prior to loading the resulting tables into the rotor front-end program.

Output:

Options on volume of line printer output for total documentation. Data files are dumped for processing with independent plotting capability (provided). Files are also dumped for on-screen simulation of rotor forced response and damped natural frequency mode shapes.

Post-Processing:

User controlled options on form and content of plots. Screen capture software required to dump the simulation program frozen images.

Hardware:

IBM PC compatible 486-25 or higher recommended.
Windows 3.1x and Windows 95 , 98, XP with some restrictions

Availability:

All executable codes are available to members of the Virginia Tech Rotor Lab Industry Affiliates. Initial membership fee of $TBD with annual fee of $12,500 per industry division.

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