ON THE STARTING OF SUPERSONIC NOZZLES WITH THE AID OF CYLINDRICAL DIFFUSERS
Abstract
The efficiency of short cylindric diffusers was experimentally investigated in a supersonic wind tunnel provided with exchangeable nozzles with a conical supersonic section designed for M equals 2; 2.5; 3.0; 3.5; 4.0; and 5. 0 and a half cone angle of alpha equals 8 degrees for all M numbers. The diffusor lengths varied from one to eight calibers of the nozzle exit cross sections. Compressed nitrogen was used as the working substance. A graph of the ratio of the aerodynamic stagnation pressure during startup of a nozzle with diffusers to the relative diffuser length showed the advantage of using diffusers at higher nozzle M values. A diffuser length of up to 3-4 nozzle calibers practically exhausts the possibility of decreasing the starting pressure of nozzles with calculated M values of less than 3. Diffuser lengths up to 6-7 calibers are expedient on nozzles for nearly hypersonic M values. Sufficiently long cylindrical diffusers have an efficiency of 0.75-0.85. Diagrams are presented for selecting minimum diffuser lengths in the range of M equals 2-5. The experiments revealed that the maximum rarefaction attainable with cylindrical diffusers at the nozzle exit section during discharge into a normal atmosphere is 0.04 atm. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 1969
- Accession Number
- AD0693611
Entities
People
- N. A. Chukhalo
- V. E. Davidson
Organizations
- National Air and Space Intelligence Center