EXPERIMENTÁLNÍ STUDIE NĚKTERÝCH ASPEKTŮ SPREJŮ TYPU „EFFERVESCENT“

Some Aspects of Effervescent Atomization: Experimental Study

habilitation thesis

en

The present work is focused on experimental study of a single-hole, plain-orifice effervescent atomizer with an outside-in gas injection configuration for combustion applications. Introductory chapter outlines main features of the effervescent atomization. Next chapter deals with two-phase flow inside the atomizer. Qualitative description of fluid mixing, internal two-phase transport and discharge of the mixture is based on published maps, analytical two-phase flow models are used for predictions of discharge of the gas-liquid mixture and compared with experimental data. Phenomenological explanation of liquid break-up and spray-gas interaction is followed with experimental description of the spray structure using Particle Image Velocimetry-Planar Laser-Induced Fluorescence technique; spatially and temporally resolved distributions of the liquid within the spray and spray cone angles are studied with respect to operation conditions of the atomizer. Spatial variation of droplet characteristics, such size and velocity distributions, are probed by means of Phase-Doppler Anemometry. Energy considerations in effervescent atomization are followed with an estimation of atomization efficiency. The last chapter describes several applications of the effervescent atomizer for waste fuel and suspension spraying.

Předložená práce systematicky shrnuje poznatky získané při experimentálním výzkumu atomizace typu effervescent. Věnuje se těmto aspektům: vnitřní dvoufázové proudění, vlastnosti spreje (velikost a rychlost kapek, hmotnostní toky ve spreji atd.), atomizační účinnost, nestability, atomizace suspenzí, návrhy trysek pro různé aplikace atd.

The present work is focused on experimental study of a single-hole, plain-orifice effervescent atomizer with an outside-in gas injection configuration for combustion applications. Introductory chapter outlines main features of the effervescent atomization. Next chapter deals with two-phase flow inside the atomizer. Qualitative description of fluid mixing, internal two-phase transport and discharge of the mixture is based on published maps, analytical two-phase flow models are used for predictions of discharge of the gas-liquid mixture and compared with experimental data. Phenomenological explanation of liquid break-up and spray-gas interaction is followed with experimental description of the spray structure using Particle Image Velocimetry-Planar Laser-Induced Fluorescence technique; spatially and temporally resolved distributions of the liquid within the spray and spray cone angles are studied with respect to operation conditions of the atomizer. Spatial variation of droplet characteristics, such size and velocity distributions, are probed by means of Phase-Doppler Anemometry. Energy considerations in effervescent atomization are followed with an estimation of atomization efficiency. The last chapter describes several applications of the effervescent atomizer for waste fuel and suspension spraying.

dvoufázové proudění, effervescent atomizace, vlastnosti spreje, suspenze, směs kapalina–plyn, atomizační účinnost

two-phase flow, effervescent atomization, spray characteristics, suspensions, gas–liquid mixture, atomization efficiency

29.03.2013

VUT Brno

Brno

1–92

92