Acoustic analysis of ram-jet buzz / by Harold Mirels.

Format:

Book

Government document

Author/Creator:

Mirels, Harold, author.

Contributor:

United States. National Advisory Committee for Aeronautics, issuing body.

Series:

Technical note (United States. National Advisory Committee for Aeronautics) ; 3574.

Technical notes / National Advisory Committee for Aeronautics ; No. 3574

Language:

English

Subjects (All):

Airplanes--Ramjet engines.

Airplanes.

Jet engines--Noise.

Jet engines.

Combustion chambers.

Physical Description:

1 online resource (33 pages) : illustrations

Place of Publication:

Washington [D.C.] : National Advisory Committee for Aeronautics, 1955.

Summary:

A one-dimensional analysis of ram-jet buzz is presented. The particular mechaniam leadlng to buzz, which is treated herein, is the amplification of acoustic waves in the ram-jet combustion chamber due to successive reflections from the inlet and exit sections.

It is assumed that the combustion chamber is of constant area and is long compared with the length of the inlet. The inlet of such a configuration operates quasi steadily, or nearly so, during unsteady operation. It is assumed that the exit operates qmsi steadily at all times. The configuration is shown to be unstable when the real part of the acoustic bpedance of the inlet is greater than a term of the order of the combustion-chamber Mach number. For quasi-steady operation, the impedance of an inlet is proportional to the slope of its characteristic curve. Increasing the combustion-chamber Mach number or decreasing the slope of the inlet characteristic curve during suibcritical operation will tend to increase the range of stable operation.

Computations indicate that burning increases the stable operating range of a given configuration. The computations assume a fixed planar flame front and a constant heat release per unit mass.

The requirement of a relatively long combustion chamber is relaxed in the appendix that treats the case of isentropic flow in the combustion chamber.

The applicability of the results for configurations wherein the inlet is replace by a compressor is mentioned briefly in CONCLUDING REMARKS.

Notes:

Title from title screen (viewed March 7, 2019).

"November 1955."

"Lewis Flight Propulsion Laboratory, Cleveland, Ohio."

No Federal Depository Library Program (FDLP) item number.

Includes bibliographical references (page 31).

Print version record.

Other Format:

Paper version: Mirels, Harold. Acoustic analysis of ram-jet buzz

OCLC:

1100474423