A study of boundary layer and mass bleed in a short length supersonic diffuser for a gas dynamic laser
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Authors
Habel, Paul Grimmer
Subjects
Laser
Gas dynamic laser
Diffuser
Boundary layer bleed
Gas dynamic laser
Diffuser
Boundary layer bleed
Advisors
Fuhs, A.E.
Date of Issue
1976-03
Date
March 1976
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
This research was conducted to study the effect of boundary layer and mass bleed on the starting (i.e., establishment of supersonic flow) and running of a short length supersonic diffuser for a gas dynamic laser. A one-dimensional diffuser geometry which diffused the flow by an isentropic turn was laid out by the method of characteristics. Extensive boundary layer bleed holes and slots were incorporated in the diffuser walls. Self-actuating, one-way valves installed in the walls bled excess flow during starting. Schlieren flow visualization was obtained through opposite glass diffuser walls. The diffuser was started and Mach 3.5 flow established in a diffuser with a contraction ratio of 1.69. This geometry would not start without utilizing boundary layer and mass bleed. A mode of operation called self bleed was discovered. The lower static pressure in the diffuser entrance, via suitable
ducting, was used to bleed the boundary layer in the diffuser throat. This method reduced the
minimum operating stagnation pressure 17.0% without utilizing vacuum tanks or pumps. Testing confirmed that boundary layer bleed in the diffuser throat significantly lowers operating
stagnation pressure.
Type
Thesis
Description
Series/Report No
Department
Aeronautics
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.