An Automaic Method for Creating the Profile of Supersonic Convergent-Divergent Nozzle

The supersonic convergent-divergent nozzles have many applications. An advanced design method must be used when the conditions are critical and wave-free stream must be reached. The characteristic method is a general technique in which the design of a nozzle can be achieved. Unfortunately, this technique can be performed only through a lengthy graphical procedure. The aim of this paper is to create an automatic way to perform the nozzle profile using the above method. Although, there are a variety of CFD FE packages that deal with nozzle design, they all require the profile of the nozzle to be started with. This research develops a new approach that helps the machine designer to create this profile. Through this work, two computational stages have been used and both with the aid of the computer. Firstly, a well-known calculation and graphical packages have been used to create the unit model matrix for each Mach number. Then, in the second stage, programming with visual basic has been used to create the profile of the nozzle automatically by multiplying the unit model matrix by the proper scale factor that is calculated according to the working requirements. User friendly software has been written for this purpose. The functionality of the method is validated by solving problems with known solutions and this approach presented logical results. This work is limited for Mach number up to 2.5 only, constant specific heat and two dimensional flows