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Coltrin, R. E.

Publications and source records attributed to Coltrin, R. E..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

A survey of inlet/engine distortion compatibility

The history of distortion analysis is traced back to its origin in parallel compressor theory which was initially proposed in the late fifties. The development of this theory is reviewed up to its inclusion in the complex computer codes of today. It is found to be a very useful tool to guide development but not quantitative enough to predict compatibility. Dynamic or instantaneous distortion methodology is also reviewed from its origins in the sixties, to its current application in the eighties. Many of the requirements for interpreting instantaneous distortion are considered and illustrated. Statistical methods for predicting the peak distortion are described, and their limitations and advantages discussed. Finally, some Reynolds number and scaling considerations for inlet testing are considered. It is concluded that the deterministic instantaneous distortion methodology combined with distortion testing of engines with screens will remain the primary method of predicting compatibility for the near future. However, parallel compressor analysis and statistical peak distortion prediction will be important tools employed during the development of inlet/engine compatibility. Previously announced in STAR as N83-27991

Bowditch, D. N.↗
NASA NTRS1983

A survey of inlet/engine distortion compatibility

The history of distortion analysis is traced back to its origin in parallel compressor theory which was initially proposed in the late fifties. The development of this theory is reviewed up to its inclusion in the complex computer codes of today. It is found to be a very useful tool to guide development but not quantitative enough to predict compatibility. Dynamic or instantaneous distortion methodology is also reviewed from its origins in the sixties, to its current application in the eighties. Many of the requirements for interpreting instantaneous distortion are considered and illustrated. Statistical methods for predicting the peak distortion are described, and their limitations and advantages discussed. Finally, some Reynolds number and scaling considerations for inlet testing are considered. It is concluded that the deterministic instantaneous distortion methodology combined with distortion testing of engines with screens will remain the primary method of predicting compatibility for the near future. However, parallel compressor analysis and statistical peak distortion prediction will be important tools employed during the development of inlet/engine compatibility.

Bowditch, D. N.↗
NASA NTRS1980

An analytical and experimental study of a short s-shaped subsonic diffuser of a supersonic inlet

A subscale HiMAT forebody and inlet was investigated over a range of Mach numbers to 1.4. The inlet exhibited a transitory separation within the diffuser but steady state data indicated reattachment at the diffuser exit. A finite difference procedure for turbulent compressible flow in axisymmetric ducts was used to successfully model the HiMAT duct flow. The analysis technique was further used to estimate the initiation of separation and delineate the steady and unsteady flow regimes in similar S-shaped ducts.

Neumann, H. E.↗
NASA NTRS1980

An analytical and experimental study of a short S-shaped subsonic diffuser of a supersonic inlet

An experimental investigation of a subscale HiMat forebody and inlet was conducted over a range of Mach numbers to 1.4. The inlet exhibited a transitory separation within the diffuser but steady state data indicated reattachment at the diffuser exit. A finite difference procedure for turbulent compressible flow in axisymmetric ducts was used to successfully model the HiMAT duct flow. The analysis technique was further used to estimate the initiation of separation and delineate the steady and unsteady flow regimes in similar S-shaped ducts.

Neumann, H. E.↗
NASA NTRS1979

Supersonic propulsion technology

Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.

Powers, A. G.↗
NASA NTRS1975

Engine systems technology

Current full-scale engine development programs are discussed, and efforts to improve the available technology base are presented. The Lewis full-scale engine test facilities are described. Several typical engine programs and plans for research in aeromechanical instability or flutter are summarized. An overview of Lewis studies of flow distortion and its effects on engine stability is presented. The origins and nature of the distortion problem are summarized, and some of the results and methods for both steady and time-varying distortions are discussed.

Willoh, R.↗