Numerical Investigation on Passive Control of Supersonic Jets using Slanted Perforated Jet Tabs

Abstract

The primary objective of this paper is to investigate the performance of C-D (converging-diverging) nozzles with slanted perforated tabs through numerical simulations. Specifically, the paper focuses on the simulation of supersonic jets controlled by these slanted perforated tabs to evaluate their effectiveness in enhancing mixing efficiency. The simulation methodology involves developing a computational model of the jet and the tabs, utilizing mathematical equations and numerical techniques to solve for fluid flow, pressure, and other relevant variables. This computational approach enables the prediction of jet behaviour and the assessment of how different types of control tabs impact the system. This helps for the design of improved jet engines and other fluid systems that require effective mixing capabilities. The introduction of tabs introduces changes to the potential core and velocity profiles, primarily due to enhanced mixing effects facilitated by the tabs. In a supersonic flow, the potential core is typically shorter than in subsonic flows due to the compressibility effects of the fluid. Even though in literature many studies have been done on sonic jets with perforated tabs and some on supersonic jets with perforated tabs, the uniqueness in this paper is on the blockage area. Blockage area has been kept at a minimum of around one percent for solid tab and for 30º perforated tab it’s as low as 0.5%. By incorporating perforated tabs into a supersonic jet, the size of the potential core can be further reduced through enhanced mixing between the jet and the surrounding fluid. Thus, with minimal thrust loss this paper explores maximum benefit of potential core reduction and thereby better mixing efficiency and lesser noise production. Solid tab has better potential core reduction but with lesser blockage area, 30º perforated tab is better in ratio of potential core reduction to blockage area.