Aerodinamičke karakteristike strujanja plina kroz nadzvučnu mlaznicu

master's thesis

• Title (english): Aerodynamic Characteristics of Gas Flow Through a Supersonic Nozzle
• Author: Ian Cvek Šekuljica
• Mentor: Karolina Krajček Nikolić (mentor)
• Committee member: Anita Domitrović (predsjednik povjerenstva)
• Committee member: Davor Franjković (član povjerenstva)
• Committee member: Ernest Bazijanac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Transport and Traffic Sciences; (Division of Aeronautics); (Department of Aeronautics); Zagreb
• Defense date and country: 2022-09-22, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Traffic and Transport Technology; Air Traffic

Abstract

Za ubrzanje struje fluida sa podzvučne na nadzvučnu brzinu koristi se konvergentno-divergentna mlaznica. Takve vrste mlaznica prisutne su u raketnim motorima ili motorima nadzvučnih vojnih mlaznih zrakoplova. Definirano je i opisano kvazi-jednodimenzionalno strujanje koje je prigodno za razmatranje karakteristika strujanja kroz nadzvučnu mlaznicu i nadzvučne difuzore. Nakon definiranja osnova strujanja fluida kroz nadzvučnu mlaznicu i difuzor, definiran je model nadzvučne mlaznice korišten pri CFD analizi aerodinamičkih karakteristika strujanja plina. Dizajn nadzvučne mlaznice opisan je metodom karakteristika. Također, metoda karakteristika je opisana ukratko kao odličan alat pri izračunu kontura zidova nadzvučne mlaznice. Mlaznica koja je dizajnirana i korištena u radu spada pod vrstu mlaznica minimalnih duljina. Za kraj prikazani su rezultati CFD analiza strujanja u slučaju viskoznog i neviskoznog strujanja. Pojava graničnog sloja se lijepo vidi pri viskoznom strujanju, te porast temperature u blizini zidova mlaznica uslijed pojave trenja. Prikazan je i slučaj pojave normalnog udarnog vala unutar mlaznice. Rezultati su validirani pomoću metode karakteristika.

Abstract (english)

A convergent-divergent nozzle is used to accelerate the fluid flow from subsonic to supersonic speeds. Such types of nozzles are present in rocket engines or supersonic military jet aircraft. A quasi-one-dimensional flow is defined and described, which is convenient for considering the characteristics of flow through a supersonic nozzle and supersonic diffusers. After defining the basis of the fluid flow through the supersonic nozzle and the diffuser, the model of the supersonic nozzle used in the CFD analysis of the aerodynamic characteristics of the gas flow was defined. The design of the supersonic nozzle is described by the method of characteristics. Also, the method of characteristics is briefly described as an excellent tool for calculating the contours of supersonic nozzle walls. The nozzle that was designed and used in the work belongs to the category of minimum length nozzles. Finally, the results of the CFD flow analysis in the case of viscous and non-viscous flow are presented. The appearance of the boundary layer is visible during viscous flow, and the increase in temperature near the walls of the nozzles due to the appearance of friction.. Results are validated by the method of characteristics.

• Keywords: nadzvučna mlaznica; stlačivost; CFD; granični sloj; viskoznost
• Keywords (english): supersonic nozzle; compressibility; computational fluid dynamics; boundary layer; viscosity
• Language: croatian
• URN:NBN: urn:nbn:hr:119:048982
• Study programme: Title: Aeronautics; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka aeronautike (magistar/magistra inženjer/inženjerka aeronautike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-12-09 15:23:36