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AD-A261 296 ", REPORT FR9201-01 ADVA.L-7 BR!SD'LE SEALS FOR GAS TURBINE ENGINES DTIC CCNTPACT PAAJ02-92-C-00O8 EB 2 4 1993 PHASE I FIN.T.L REPORT COVEMING PERIOD CF MAY THRU NOVEMBER 1992 SUBMITTED JANUARY 1993 By ENGINEERED DESISNS, INC. CINCIMNATI, OHIO 45245 | -o Approved for public release, distribution' is unl imited. 1 REPORT DOCUMENTATION PAGE I AGENCY USE ONLY 4#4-te 01400 J REPORT DATE 3 RPOkTF TV*( ANDO OA~tS COYESIDr 28 January 1993 lFinal Report, May - .uvemteerr 4- TITLE ANO SUBTITLE S t NuMjkioIk~ $ ADVANCED BRISTLE SEALS FOR GAS TURBINE FNGINES DAAJO2- 2-C-i>C2 -. AUTo..RS) Cabe, Jerry L. 7. PERFORMING ORGANIZATION NAME(S) AN' ADOOESS(.S) B #ERIOa*A(cid:127)NC OCGANWIAtiON ftEPOPI humola Engineered Designs, Inc. 4733 Devitt Drive FR9201-01 Cincinnati, Ohio 45246 9-S PONSORING/MONITORING AGENCY NAME(S) APND AIDOESS({.S) 10 SPONOfItNG MONITON11 Department of the Army AGENCY RIPOAT Nu;MjB Aviation Applied Technology Directorate U.S. Army Aviation and Troop Command (AlMSAT-R-TP) Fort Eustis, VA 23604-5577 11, SUPPLEMENTARY NOTES 12a. OISTRIBUTION1 AVAIkABILITY STATEMENT t~b DISTRIBUTION COOT 13. ABSTRACT (Mawsmum 200 words) A seven month proof-of-concept program was conducted for an advanced br ;ýtie seal, called a bush seal, for use in gas turbine engines. This program win, performed as a Small Business Innovation Research (SBIR) Phase I project. Bush seal specimen and a full ring bush seal were designed, evaluated, ard manufactured for testing. An analytical study of the potential of the th/ seal relative to a labyrinth seal was conducted. Static and dynamic tes'.-I of the bush seal was performed to determine the behavior of the bristles under pressurization and during contact with a rotating labyrinth tooth. Stable behavior of the bristle elements was observed during static pressurization of a full ring bush seal. The dynamic testing of vario.,us configurations of bush seal against a rotating labyrinth tooth showed - wear of the bristles relative to a conventional labyrinth seal. The development and application of the bush seal concept to gas turbine engines has the potential of improving the engine's performance while decreasing the degradation of the seal performance over time. 14. SUBJECT TERMS 15. NUMBER OF PAG,8 40 Seal, Bush Seal, Labyrinth Seal, Gas Turbine 1 PRICEODE... 17. SECURITY CLASSIFICATION 1' SECURITY CLASSIFICATION 19 SECURITY CLASSIFICATION 20. LIMITATION OF ARSTA(T OF REPORT Of THIS PAGE OF ABSTRACT I UNCLASSIFIED I NSN 754001,280-5500 S0aded Fe~r (cid:127)g8 , , (This Page Intentionally Left Blank) ii PREFACE This report describes the work performed by Engineered Designs, Inc., Cincinnati, Ohio, under Department of the Army Contract DAAJ02-92-C-0008. This is the final report and covers the period of May 1992 to November 1992. This program was aimed at determining the feasibility of an advanced bristle seal concept for application to gas turbine engines. This proof-of-concept program was sponsored under the Department of the Army Small Business Innovation Research (SBIR) program~by the U.S. Army Aviation and Troop Command (ATCOM) ,Aviation Applied Technology Directorate (AATD), Fort Eustis, Virginia. The Technical Contracting Officer's Representative was Mr. Philip LaFerriere of AATD. The Principal Investigator and Program Manager was Jerry Cabe of Engineered Designs, Inc. t971C QUAUYIN-:(cid:127) YX1r* ,+*iw-(cid:127),r-, +p 4 LACCS was initiated by Aviation Systems Command (AVSCOM) *Program prior to organizational name change in October 1992. iii (This Page Intentionally Left Blank) iv CONTENTS Page PREFACE ...................................................... iii LIST OF FIGURES .............................................. vi LIST OF TABLES ............................................... vii BUSH SEAL CONCEPT SUMMARY .................................... 1 PHASE I PROGRAM OBJECTIVES ................................... 3 WORK CARRIED OUT DURING PHASE I .............................. 4 RESULTS OF PHASE I ........................................... 12 CONCLUSIONS BASED ON PHASE I EFFORTS ......................... 28 APPENDIXES A. STATIC TEST HEAD ASSEMBLY DRAWING - P893A001 ....... 30 B. VERMESE ORIFICE EQUATION ........................... 33 C. BUSH SEAL STATIC TEST DATA ......................... 34 v FIGURES 1 Bush seal concept .................................... 1 2 Bush seal Phase I schedule ......................... 5 3 Bristle bundle as welded ............................ 6 4 Static test air system schematic ................... 8 5 Test plan for static test of bush seal ............. 9 6 Bush seal subscale specimen ........................ 13 7 Full ring bush seal test article ................... 14 8 Bush seal test article surface after machining ..... 15 9 Static test head as assembled with spacer .......... 16 10 Loose bundle area of test article before testing... 18 11 Loose bundle area of test article after testing.... 19 12 Test Sequences A & B varsus predicted flow ......... 20 13 Simple orifices versus predicted flow .............. 21 14 Machined ring versus predicted fl(cid:127)w ................ 21 15 Test setup with .003 inch shim installed ........... 22 16 Test Sequences A, B, G, & H versus predicted flow.. 23 17 Test setup wit' .003 inch shim and RTV seal ........ 23 18 Test setup with RTV seal ........................... 24 19 Shimmed and RTV sealed tests versus predicted flow. 24 A-1 Static Test Head Assembly drawing - P893A001 SH 1.. 31 A-2 Static Test Head Assembly drawing - P893A001 SH 2.. 32 vi TABLES 1 Parasitic air leakage at T700 seal locations ........ 17 2 Bush seal dynamic test matrix ....................... 25 3 Bush seal dynamic test wear measurement ............. 26 4 Bush seal extended duration test .................... 26 C-i Test Sequence A data ................................ 35 C-2 Test Sequence B data ................................ 35 C-3 Test Sequunce C data ................................ 36 C-4 Test Sequence D data ................................ 36 C-5 Test Sequence E data ................................ 37 C-6 Test Sequence F data ................................ 37 C-7 Test Sequence G data ................................ 38 C- Test Sequence H data....................................38 C-9 Test Sequence I data ................................ 39 C-10 Test Sequence J data ................................ 39 vii (This Page Intentionally Left Blank) viii BUSH SEAL CONCEPT SUMIARY In 1988, Engineered Designs, Inc. initiated the development of an innovative bristle seal concept for use in gas turbine engine applications. This early development effort was limited to conceptual design and manufacturing methods evaluations. In May 1992 a contract between AVSCOM and Engineered Designs, Inc. was initiated to developoan advanced bristle seal with operational capabilities to 1450 F and 1450 feet per second tip speed evolving from the previous work. This contract effort was conducted as a Phase I Small Business Innovation Research (SBIR) program. The advanced bristle seal covered by this contract is called a "bush seal". Figure 1 compares the features of a conventional labyrinth seal with those of a bush seal. Because the bush seal does not have to be designed for the worst case of combined thermal, mechanical, and rotor movement effects, the initial radial gap can be smaller than that of the conventional labyrinth seal. The bush seal's radial gap will also not be permanently increased during rubs caused by transients or rotor excursions as in a conventional labyrinth seal with abradable surfaces. This is because the bristles of the bush seal are spread apart during a STAlIONAAY MER "(cid:127)-ED O IATEIIAL / kO14tWALC AP LAS-*INTKT EE(cid:127)TS / O WITh COATING - ITA¶IWN "(put WIf* PISILEs CONVENTIONAL LABYRINTH SEAL STAItIA -- IN S. LA UIIIT 5TIE1TR ." WITN COING BUSH SEAL FIGURE 1. BUSH SEAL CONCEPT 1