Design of Maximum Thrust Plug Nozzles for Fixed Inlet Geometry
Abstract
The techniques of the calculus of variations were used to determine the configuration of an optimum thrust plug nozzle. The problem is formulated for a fixed thrust injection angle and cowl lip radius, and the resulting plug contour is then an optimum for a given upstream geometry. The optimum values of the injection angle and cowl lip radius are determined by a parametric study. The analysis is carried out for rotational and irrotational flows and includes boundary layer effects. A method is presented for each of the problem formulations to determine if a given contour is an optimum and a relaxation technique is used to obtain a solution to the irrotational flow problem. A computer program which makes use of the design equations for the irrotational flow problem is developed and described. This program is used to carry out a parametric study to determine the optimum cowl lip radius and injection angle when the plug length is fixed. The resulting optimum nozzle is compared to one designed by Rao's Method. The importance of determining the base pressure accurately is illustrated and an example of scramjet nozzle optimization is presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1970
- Accession Number
- AD0872104
Entities
People
- H. Doyle Thompson
- Joe D. Hoffman
- Robert P. Humphreys
Organizations
- Purdue University