Effect of Liquid Properties on Heat Transfer from Miniature Heaters at Different Gravity Conditions

Abstract

This work presents experiments for the estimation of heat transfer from sub-millimeter spheroidal heaters at varying gravity conditions. Experiments were performed during the 50 th Parabolic Flight Campaign of European Space Agency (May 2009). Heat pulses of varying strength were given to a miniature heater submerged in the liquid while its thermal response was registered during heating. Tests were conducted in water and FC-72, two liquids with distinctly different thermophysical properties. Runs were also conducted with packed beds and dense suspensions of two size classes of polystyrene particles in water. The contribution of natural convection in heat transfer was estimated from differences observed when the acceleration varied from 0g to 1.8g. Although the analysis of data is not finished yet, it is evident that natural convection is more profound in FC-72 than water. In addition, closely packed particles suppress entirely natural convection but this is not so for dense particle suspensions.

Flow Patterns and Heat Transfer in a Cylindrical Annulus under 1g and low-g Conditions: Theory and Simulation

“…Another application for this geometry is the control of the heat transfer by dielectrophoretic force. In particular, the heat transfer and its control under reduced gravity condition are in the focus of attention of researchers (Evgeridis et al 2011;Lotto et al 2017). Experiments have been performed under Earth's gravity conditions (Chandra and Smylie 1972), and many theoretical and numerical works have been done considering microgravity conditions in order to focus on the effects of the thermoelectric buoyancy (Takashima 1980;Malik et al 2012;Yoshikawa et al 2013;Travnikov et al 2015Travnikov et al , 2016.…”

Μελέτη Δυναμικής Φυσαλίδων Κατά Την Απαερίωση Υγρών

“…Η αναγωγή αυτή δεν είναι πάντοτε ορθή. Στο παρελθόν, πειραματικές μελέτες επάνω στη μεταφορά θερμότητας απουσία βαρύτητας έδειξαν διαφορετικά αποτελέσματα από αυτά που προέβλεπαν τα θεωρητικά μοντέλα (Kostoglou et al, 2011;Evgenidis et al, 2011;Kostoglou et al, 2013, Lioumbas et al, 2017. Έτσι, οι πειραματικές μελέτες απαερίωσης σε συνθήκες υπερβαρύτητας προσφέρουν τη δυνατότητα της επιβεβαίωσης των θεωρητικών μοντέλων.…”