& Mobility DEVELOPMENT OF AN EFFICIENT, LEAK PROOF PLENUM SEAL - - PowerPoint PPT Presentation

Power & Mobility

8/21/2018

DEVELOPMENT OF AN EFFICIENT, LEAK PROOF PLENUM SEAL FOR THE M1 ABRAMS ENGINE INLET

Steve Tarnowski Steve Pennala Great Lakes Sound and Vibration Inc.

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Background

• The plenum seal couples the M1 turbine engine inlet to the air

intake plenum.

• Several factors lead to foreign object debris (FOD) and water

ingestion past the seal, leading to premature wear on turbine compressor blades and other components.

– Dimensional variations among vehicles causes extreme misalignment between the plenum box and the turbine inlet – Ability of the seal to properly engage the plenum box outlet ring – Difficulty in accessing the seal to ensure proper installation before engine startup

• GLSV worked with TARDEC GVPM to develop a new plenum seal

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018 DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Goals

• Significantly improve sealing performance and

reliability

• Simplify seal installation, both on the engine

and on the plenum box during powerpack installation

• Provide a means to easily verify proper

installation

• No changes to the plenum box or turbine

inlet/FOD screen

• Maintain or reduce current seal procurement

costs

Current plenum seal installed on turbine FOD screen assembly

Power & Mobility

8/21/2018

Challenges

• Need to account for large dimensional

variation between the turbine inlet and the plenum box outlet

• Blind installation of the seal during

power pack installation

– Seal installation trajectory leading to the final seated position

• Extreme operating environment

– Ambient temps from -60°F to 300°F – Chemicals such as turbine fuel, engine oil, hydraulic oil, etc. – Shock and vibration

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Design Requirements

• Sealing envelope

– GLSV measured twelve M1 engine compartments and powerpacks at the Anniston Army Depot (ANAD) to quantify the variance in alignment between the turbine inlet and plenum outlet – Measurements were taken using high precision laser-scanning equipment. – Measured data was compared to hull drawings to completely define the sealing envelope

• Flexural strength, durability and environmental requirements were taken from the

current production seal drawing

CAD assembly based on vehicle scan data

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Seal Design Process

• GLSV developed the seal design specification based on the

expected range of misalignment.

• The misalignment specification was based on vehicle

measurements, combined with a tolerance stackup based on vehicle hull drawings.

• GLSV created 3D CAD models of the power pack, plenum box,

and hull interface points. These assembly models were used to simulate the motion trajectory during powerpack installation into the vehicle.

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Seal Design Process

• In addition to the final installed misalignment, the simulated

installation trajectory path was also considered in the seal design process:

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Seal Design Process

• Seal material selection considered the best compromise of

material properties to meet the environmental requirements.

• Several seal design concepts were developed, considering

material and processing requirements and manufacturing considerations.

• Preliminary finite element analysis (FEA) was performed to

evaluate sealing/leakage performance for the expected range of misalignment.

• One seal concept was eventually down selected for further

design optimization.

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Seal Design Process

• 2D axisymmetric FEA was performed to

rapidly optimize the seal and zero in on favorable seal geometry.

• Detailed 3D FEA was performed to include

the seal, FOD screen, plenum ring, and a partial model of plenum box.

• Simulated the seal stretched over the

plenum ring, with applied radial clamp force.

• Combined radial and axial offsets were then

applied.

• FEA predicted seal stress/strain and sealing

contact pressures.

FE Model of Seal Assembly

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Prototype Development

• Molding process was developed to validate

manufacturability and provide prototype seals for lab testing and vehicle fit checks:

– Single cavity transfer mold – Several molding trials were conducted to produce good parts – Tooling and transfer molding method were developed with production intent – Minor modifications/improvements will yield consistent, high quality parts in production

• Prototypes molded with FVMQ and HNBR rubber

– FVMQ offers resistance to extreme temperatures and weather – HNBR offers superior abrasion resistance and flexural strength

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Lab Testing

• Comparative lab tests of new FVMQ and HNBR

prototypes and current production seal

– High temp leakage performance – Installation and leakage performance through the range of misalignments – Combined environment leakage performance (high temp and vibration) – Water submersion

• Leak test fixture simulates the vehicle seal

installation procedure, and can pull up to 100 iwg vacuum

– Seal is translated through the installation trajectory and onto the plenum ring with force provided by hydraulic jacks – Fixture is completely sealed and vacuum pump pulls a vacuum on the simulated plenum box

• Lab tests shows the GLSV seal would perform

well on all twelve vehicles measured at Anniston.

GLSV custom designed lab test fixture

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Vehicle Installation Trials

• GLSV assisted ANAD mechanics with seal installation trials and

fit checks with the prototype seals.

• Four install/removal trials were performed on two vehicles.
• The seal geometry and design features allowed for successful

hands-free installation and removal.

– Proper seating/engagement of the seal was verified by remote video cameras mounted inside the engine compartment.

• GLSV received positive feedback from ANAD personnel

– The prototype seal was easier to install on the FOD screen and engaged more smoothly with the plenum ring during power pack installation. – Also provides positive visual proof of proper seal engagement

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.

Power & Mobility

8/21/2018

Conclusions

• GLSV’s new plenum seal performed well in lab tests.
• GLSV’s seal has improved vacuum leakage performance for a

wider range of misalignment conditions.

• GLSV seal performed well at elevated temperatures while

undergoing vibration.

• GLSV’s seal performed well in vehicle installation trials.
• GLSV anticipates additional design improvements during the

upcoming Phase-III SBIR effort to build on the previous work.

• Our end goal is to have a production level TDP and

production-intent tooling for our new plenum seal design.

DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited.