Exploratory development of a twin-spool turbocharger for a high-output diesel engine. Final report, September 1983-June 1986

Technical Report · Fri Aug 01 04:00:00 EDT 1986

OSTI ID:6295153

Hess, R; King, J F; Harp, J L

The analysis, design, fabrication, and experimental testing of a twin-spool turbocharger was conducted for the Cummins NTC-475 diesel engine. Two major designs of the twin-spool turbocharger were fabricated and tested: 1) Compact design, concentric shaft-to-shaft bearing coupled turbocharger incorporating a) split 40/sup 0/ backswept impeller, b) split AiResearch Ti8A85 turbine rotor, c) adjustable vaned compressor diffuser, and d) nozzleless AiResearch turbine (volute) housing; and 2) Independently supported (shafts dynamically de-coupled) concentric shaft design incorporating a) separate structures for bearing support of the inner shaft b) split 25/sup 0/ backswept compressor impeller, c) split T18A40/Ti8A85 turbine rotor/exducer combination, and d) divided volute, adjustable-nozzle turbine housing. While bench tests were performed on both designs, engine testing was successfully carried out using the latter designs. Tests indicated that the second twin-spool configuration gave performance comparable to the originally equipped two-stage turbocharger system of the NTC-475 diesel engine (rated BHP of 425 hp at 2100 RPM, best BSFC of 0.35 at engine lug) with the added benefit of extending engine lugging range to 1200 RPM (from 1300 RPM, as originally equipped). This configuration gave peak compressor efficiency of about 75% and peak turbine efficiency of about 80%, both attributed to the reduction inducer angle of attack and exducer exit swirl angle made possible by the twin-spool concept.

• Research Organization: Thermo Mechanical Systems Co., Canoga Park, CA (USA)
• OSTI ID: 6295153
• Report Number(s): AD-A-181273/4/XAB; SR-41
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330102* -- Internal Combustion Engines-- Diesel
BEARINGS
CHEMICAL REACTIONS
COMPRESSORS
DIESEL ENGINES
DIFFUSERS
EFFICIENCY
ENGINES
FABRICATION
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MACHINERY
NOZZLES
REDUCTION
SUPERCHARGERS
TESTING
TURBINES
TURBOCHARGERS
TURBOMACHINERY