1. Comparative study of the cooling of a hot temperature surface using sprays and liquid jets
- Author
-
Michel Gradeck, Alexandre Labergue, Fabrice Lemoine, Laboratoire Énergies et Mécanique Théorique et Appliquée (LEMTA ), and Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Spray characteristics ,Mass flux ,Materials science ,020209 energy ,Nozzle ,Thermodynamics ,02 engineering and technology ,01 natural sciences ,010305 fluids & plasmas ,Spray nozzle ,Hot Temperature ,[SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] ,Physics::Fluid Dynamics ,[SPI]Engineering Sciences [physics] ,Phase (matter) ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Phase Doppler analysis ,Fluid Flow and Transfer Processes ,Spray cooling ,Mechanical Engineering ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,Mechanics ,Condensed Matter Physics ,Spray heat transfer ,Heat flux ,Thermography ,Inverse conduction problem ,Infrared thermography ,[SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph] - Abstract
International audience; This experimental work aims at investigating the cooling of hot surfaces by using full cone sprays; comparison with the use of a liquid jet is also considered. The wall is a 175 mm diameter nickel disk and 5 mm thickness heated by electromagnetic induction up to about 800 °C. In the case of the sprays, the goal is to link the spray properties with the heat flux removed from the heated surface. For the spray, the influence of the mass flux distribution as well as the droplets properties on the cooling are studied by using three different spray nozzles. The mass flux distribution for each of the sprays is measured with the help of a patternator. The heat removed during the cooling phase is investigated with the use of infrared thermography while the droplet properties are characterized simultaneously by a Phase Doppler system. The Phase Doppler technique is mainly applied to study the statistical properties of the outcom-ing droplets in the vicinity of the heated surface. A decrease of the outcoming droplets size compared to the incoming one is well observed. Moreover, Phase Doppler device has also highlighted that the presence of the surface may have a significant influence on the upstream spray flow. Compared to the liquid jet, heat flux measurements have clearly demonstrated that the sprays lead a more spatial uniformity of the extracted heat flux and a better cooling efficiency. When spray cooling is considered, the influence of the mass flux on the heat flux and the cooling efficiency is in qualitative agreement with previous studies performed in similar conditions. In addition, a comparative study of performances, in term of liquid consumption and cooling duration, is performed by considering a similar surface temperature decrease for the three sprays and the liquid jet. Among the four experiments, the liquid jet has the longest cooling time as well as the highest liquid consumption. Furthermore, the best performances are reached for the spray having the highest mass flux value.
- Published
- 2014