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ROMAC Rotating Machinery and Controls Laboratory |
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Bearings and Seals Student: Minhui He Advisor: Paul Allaire Project Start Date: September 1996 Project Objectives: Develop a new finite element bearing code to accurately model fluid film journal bearings, including the bearings with new oil feeding features (leading edge groove, spray bar…) and complex flow conditions (axial flow…) Progress in the Past Year: Successfully wrote and tested the code that models regular fixed geometry bearings, i.e. the new code at present does the same work as THBRG.
Student: Rob Prior/Bob Brechting Advisor: Lloyd Barrett and Ron Flack Project Start Date: 1988 Progress in Last Year: Experimental measurement of fluid film bearing coefficients continues with the investigation of bearing coefficients as a function of bearing load angle. A complete review of the test rig systems, data acquisition codes, and post test data processing codes for calculating bearing dynamic properties has been performed by Rob Prior. This has resulted in some changes to the uncertainty analysis. The bearing coefficients for a five pad, rocker-back pivot type with a preload of 0.3 were measured at various load angles from load on pad to load between pad. Comparisons of the measured coefficients with the analytically predicted coefficients show fairly good agreement. In addition to reviewing the test rig set up and post test data acquisition processing, this research has also provided the opportunity for testing procedures to be developed and documented. The results of this testing and the system review will be reported in Rob's MS thesis which will be available by the next ROMAC Annual Meeting. A new MS student, Bob Brechting, has joined ROMAC to continue research with the fluid film bearing test rig. He has been working with Rob to become familiar with the rig and testing procedures. The rotor and drive have successfully been run at 4900 rpm. Work has begun on increasing the rotor speed of the test rig from 2500 rpm to 7500 rpm. After completing preliminary tests, running the rig without a test bearing, to show that the rotor and drive system are stable, testing will resume. Initial testing will consist of measuring static operating position and oil film heat generation.
Labyrinth Gas Seal Code/Program Development Student: Jinhui Chen and Jie zhou Advisor: Paul Allaire Project Start Date: 1997 Project Objectives: Develop a new gas labyrinth seal analysis program named LABY4, which will replace the LABY3. Labyrinth seals are composed of seal teeth and chambers between the teeth. Both the teeth-on-rotor and teeth-on-stator conditions will take into account, so does the interaction of both conditions. We try to give out the detail flow field and the rotor dynamic coefficient stiffness and damping. Progress in the Past Year: By using the three volume approach ( The seal is divided into 3 volumes: volume 1, the volume over the seal teeth; volume 2, the volume over the seal chamber; and volume 3, the seal chamber.) and bulk flow equations, the zeroth order code and the first order perturbation code have been written and verified for teeth-on-rotor conditions. The 3-D fluid flow code TASC flow, by AEA, is being used to evaluate details of the flow and improve the computer code.
Hydrostatic Bearing/Programming and Document Writing Student: Jie Zhou Advisor: Paul Allaire Project Start Date: October 2000 Report Number: John Kocur’s dissert. Project Objectives: Complete and integrate an existing Code, (HYDROB by John Kocur) for release as a ROMAC program. The final version will be released by March 2001. In addition, we are extracting a manual for HYDROB from John Kocur’s dissertation. Progress in the Past Year: Four subroutines with copyright have been replaced by our own version. The skeleton of the manual is set up.
T. Brockett and L. Barrett ROMAC has undertaken a project to modify the fixed and tilting pad bearing program THRUST to include tilting circular pad geometries. It is anticipated that these modifications will be completed by the next Annual Meeting in June 2001. Specific tasks involved in this effort include the following:1. Modify the I/O of the code to allow additional pad option, checking of input, printout of input. 2. Modification to Reynolds solution algorithm to allow for circular pads. This requires a new "crude block" meshing subroutine that defines the crude block nodal coordinates. The 2-D mesher then takes that information and determines the actual mesh. 3. A subroutine will be developed to define crude block mesh of the energy equation in the film. Once defined, the 3-D mesher determines 3-D mesh for the film. 4. Modification of the current flow calculation subroutine that uses the four "sides" of a sector to determine flows into and out of the pad using the Reynolds solution pressures. 5. The subroutine calculating the flux entering the runner will also be modified. Currently, it assumes equal contribution from all of the energy elements along the pad in the circumferential direction for any given radial coordinate. The thrust disk is in "contact" with the energy elements to different amounts in the circular pad, however. 6. Modify the THRUST scripts for the scripted editor to reflect additional options 7. Update the manual to include the additional options in the code, include any additional theory used, add an example to illustrate the new capabilities.
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