Nozzle Flow Separation Phenomena and Control for different conditions

Abstract

A detailed study of separated nozzle flows has been conducted. For a subscale, non-axisymmetric, two-dimensional, convergent divergent nozzle, schlieren flow visualization was acquired along with measurements of force, moment, and pressure as part of an extensive static performance evaluation. Additionally, two-dimensional numerical simulations were performed using the computational fluid dynamics package PAB3D together with algebraic Reynold’s stress modelling and two-equation turbulence closure. This study's experimental findings show that shock-induced boundary layer separation, which was classified into two distinct flow regimes: three-dimensional separation with partial reattachment and entirely detached two-dimensional separation, dominated off design over expanded nozzle flow. The impact of variable shock generation and reflections in various nozzle types on the two primary separation modes, namely Free and Restricted Shock Separation (FSS & RSS), is investigated. The flow separation problem in rocket nozzles has been an unwelcome phenomenon for engineers ever since the birth of the space era. Naturally, the engineers were given the job of bringing things under control. But it proved to be a difficult endeavor; despite the fact that many people were able to explain the physics underlying this occurrence, it is still not completely understood today.