Title

Insight into instabilities in burning droplets

Authors

Authors

A. Miglani; S. Basu;R. Kumar

Comments

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Abbreviated Journal Title

Phys. Fluids

Keywords

MULTICOMPONENT DROPLETS; HOMOGENEOUS NUCLEATION; PRECURSOR DROPLETS; SUPERHEAT LIMIT; SOLID-SURFACE; HIGH-PRESSURE; IMPACT; MICROEXPLOSION; EVAPORATION; COLLISION; Mechanics; Physics, Fluids & Plasmas

Abstract

The complex multiscale physics of nano-particle laden functional droplets in a reacting environment is of fundamental and applied significance for a wide variety of applications ranging from thermal sprays to pharmaceutics to modern day combustors using new brands of bio-fuels. Formation of homogenous nucleated bubbles at the superheat limit inside vaporizing droplets (with or without nanoparticles) represents an unstable system. Here we show that self-induced boiling in burning functional pendant droplets can produce severe volumetric shape oscillations. Internal pressure build-up due to ebullition activity ejects bubbles from the droplet domain causing undulations on the droplet surface and oscillations in bulk. Through experiments, we establish that the degree of droplet deformation depends on the frequency and intensity of these bubble expulsion events. In a distinct regime of single isolated bubble residing in the droplet, however, pre-ejection transient time is identified by Darrieus-Landau evaporative instability, where bubble-droplet system behaves as a synchronized driver-driven system with bulk bubble-shape oscillations being imposed on the droplet. The agglomeration of nanophase additives modulates the flow structures within the droplet and also influences the bubble inception and growth leading to different levels of instabilities. (C) 2014 AIP Publishing LLC.

Journal Title

Physics of Fluids

Volume

26

Issue/Number

3

Publication Date

1-1-2014

Document Type

Article

Language

English

First Page

16

WOS Identifier

WOS:000334179400010

ISSN

1070-6631

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