The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 02, 1989
Filed:
Feb. 26, 1989
Robert E Betts, Huntsville, AL (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
In a method for determining and evaluating nozzle erosion rate, an eroding ozzle and a non-eroding nozzle are employed in a dual nozzle arrangement to receive a balanced thrust and flow rate from a common solid propellant grain of a solid propellant rocket motor when initially fired. When erosion of the eroding nozzle begins an increase in throat area results and the mass discharged through throat increases thereby causing an imbalance in thrust. The erosion is correlated to the mass flow rate of the solid propellant rocket motor by the mathematical relationships, F.sub.2 P.sub.C.sbsb.2 (A.sub.t.sbsb.2 +.DELTA.A.sub.t.sbsb.2)C.sub.F.sbsb.2, wherein F.sub.2 is force, P.sub.C.sbsb.2 is chamber pressure, A.sub.t.sbsb.2 is throat area, .DELTA.A.sub.t.sbsb.2 is change in throat area due to erosion, and C.sub.F.sbsb.2 is the thrust coefficient. Thus, the erosion rate of the eroding nozzle is determined and evaluated as a result of the increase of thrust and the flow rate which causes an imbalance in the thrust due to erosion products discharged and a change in value of the A.sub.t.sbsb.2 plus .DELTA.A.sub.t.sbsb.2.