Development of a Noncontacting Mechanical Seal for High Performance Turbocharger Applications

Abstract

This paper presents the design and development of a noncontacting dry-gas mechanical seal for high performance automotive turbocharger applications. Turbochargers are increasingly being incorporated into high performance automobile engines to improve fuel efficiency, enhance energy recovery, and increase horsepower as compared with similar sized naturally aspirated engines. Minimizing the wear rate of tribological surfaces in the turbomachinery is critical to maximizing the reliability and durability of the turbocharger. A dry-gas seal for turbochargers and related technologies with 2–4 cm shafts has been developed. The seal provides a complete barrier between the bearing oil and compressor flow path and is capable of reverse pressure and high speed. The seal performance was evaluated for speeds between 60,000 and 80,000 rpm, pressure differentials between −0.8 (reverse pressure) to 6 bar, and temperatures between 20 and 200 °C. Structural and thermal response of the seal components to the operating conditions are analyzed using finite element methods and the tribological behavior of the seal rings are analyzed using computational fluid dynamics. The design is experimentally validated in a seal test stand. This novel approach reduces turbocharger blowby and shows no measurable wear when compared with piston ring seals.