Introduction

Background

Objectives


Test facility

Measurement techniques


Disintegration regimes

Secondary atomization within the various boiling regimes

Boiling morphology at liquid-solid interface

Heat transfer and droplet dynamics on surface enhanced surfaces






 

 
Dynamics of impacting droplets

micro nano engineering
   

  Introduction

The impact of droplets onto solid surfaces occurs in a variety of technological and environmental processes. Improved understanding requires a better knowledge of the thermo-fluid-dynamic mechanisms of interaction between the impacting droplet and the surface.

Studies are conducted on the disintegration mechanisms from impacts onto cold and heated surfaces within the various boiling regimes. Systematic experiments consider individual droplets impacting onto various rough targets made of different materials and encompass a wide range of Weber, Reynolds and Ohnesorge numbers. Surface wettability and topography, as well as liquid properties and impaction angles are systematically varied and their relative importance is discussed within the different boiling regimes. The analysis addresses the morphology of disintegration and secondary droplet characteristics (size and velocity distribution, number and ejection angles). The emphasis is put on the effects of the nature of the surface.



Projects
The research activities are supported by projects which provide the necessary external funding, namely from national and international funding agencies and/or private companies. The current investigation has contributed to the following projects:

“DYNAMIC BEHAVIOUR OF CRYOGEN SPRAY COOLING”, Project POCTI/EME/57944/2004. 2005-2008.

“FLOW AND HEAT TRANSFER CHARACTERISTICS OF EVAPORATING IMPINGING SPRAYS”, Project POCTI/1999/EME/32960. 2001-2004.

“DIRECT INJECTION ENGINE SPRAY PROCESSES-MECHANISMS TO IMPROVE PERFORMANCE”, FP5, ENK6-CT-2000-00101. 2000-2003.