Faculty & Research

personnel profile

James P. Johnston

 
Title:Professor Emeritus
Department(s):Mechanical Engineering
Location:Mechanical Engineering
Bldg 530, Room 205
Mail Code:3032
E-mail: jpj@stanford.edu

Research Statement

He was Chairman of the Thermosciences Division, 1985/90, and Associate Chairman of the Mechanical Engineering Department, 1992/94. Before joining the faculty of the Mechanical Engineering Dept. of Stanford University in 1961, he worked at Ingersoll-Rand Company as a research engineer (1957/61). He became emeritus in 1994. Research and teaching covered many areas of fluid dynamics, gas dynamics, and thermodynamics with a particular emphasis on areas where basic knowledge had important impact on the performance of flow machinery (turbines, compressors, pumps, diffusers, nozzles, etc.). Twenty-five graduate students earned their Ph.D. degrees under his supervision.

Primary Interests:

1. Turbulent boundary layer separation, reattachment, and control of stall. Control of flow separation and stall by active and passive means for internal flows, e.g. diffusers. Recent work concentrated on use of Vortex Generator Jets, the VGJ method, for active generation of longitudinal vortices as replacements for solid vortex generators for separation control.

2. Flow in, performance of, and the design of Diffusers. The prediction of subsonic flow in diffusers has advanced in recent years, but a method developed in the late 1970's and early 80's, the Unified Integral Method, still appears to be useful for rapid estimation of diffuser performance. This method is reviewed in our 1998 J. of fluids Engineering paper.

3. Micro-scale gas turbine power generator. From 1999 through 2002, a very small gas turbine engine/generator with design output of 100 Watts was under development by the Stanford Rapid Prototyping Laboratory directed by Prof. F.B. Prinz. We assisted to his group in regards the gas dynamics and fluid dynamics in the turbomachinery. A high-speed, radial-flow compressor, radial-turbine and shaft assembly (12 mm rotor diameter) was manufactured as a single component from Silicon Nitride, a material chosen to withstand temperatures as high as 1300 degrees C. Aerodynamic performance experiments at reduced speed (420,000 rpm) and CFD at design speed (800,000 rpm) for the compressor impeller showed that it should meet design requirements (Pr = 3 and efficiency of 65% at design point flow rate of 2.4 g/sec).

Publication TitleAuthor(s)/Speaker(s)Open Document
Micro-scale Radial-Flow Compressor Impeller Made of Silicon Nitride - Manufacturing and Performance S. Kang; J.P. Johnston; T. Arima...
Performance of a micro-scale radial-flow compressor made of silicon nitride J.P. Johnston; S. Kang,; T. Arima...
Vortex generating jets, effects of jet-hole inlet geometry J.P. Johnston; B.P. Mosier; Z.U. Khan
On Vortex Generating Jets Z.U. Khan; J.P. Johnston
Pitched and Skewed Vortex Generator Jets for Control of Turbulent Boundary Layer Separation: a Review J.P. Johnston
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Academic Honors & Awards

Freeman Fellowship from the ASME (1967)
ASME's Robert T. Knapp research paper award (1975)
AIAA Survey Paper citation (1981)
Elected as a Fellow of ASME in 1984
He has served as Associate Editor of the Journal of Fluids Engineering.>
He is currently a life member of ASME.
He is the author of over 90 published papers, several book chapters and many conference papers and reports.