Convective Boiling Between 2D Plates: Microgravity Influence on Bubble Growth and Detachment

Abstract

The experiment detailed in this paper presents results obtained on the nucleation, growth and detachment of HFE-7100 confined vapour bubbles. Bubbles are created on an artificial nucleation site between two-dimensional plates under terrestrial and microgravity conditions. The experiments are performed by varying the shear flow by changing the convective mass flow rate, and varying the bubble nucleation rate by changing the heat flux supplied. The experiments are performed under normal (1 g) and reduced gravity (μg). The distance between the plates is equal to 1 mm. The results of these experiments are related to the detachment diameters of bubbles on the single artificial nucleation site and to the associated effects on the heat transfer by the confinement influence. The experimental device allows the observation of the flow using both visible video camera and infrared video camera. Here, we present the results obtained concerning the influence of gravity on the bubble detachment diameter and the images of 2D bubbles obtained in microgravity by means of an infrared camera. The following parameters: nucleation site surface temperature, bubble detachment diameter and bubble nucleation frequency evidence modifications due to microgravity.

Evaporation, boiling and explosive breakup of heterogeneous droplet in a high-temperature gas

“…At the same time, the special analysis of the processes of formation and growth of bubbles under the considered conditions is important. These processes are rather specific and represent a fascinating and independent scientific problem [47][48][49][50][51]. The solution of this problem will allow widening the concepts of the boiling regimes at inside interfaces and possible approaches to intensification of the boiling in heterogeneous droplets.…”

Direct numerical simulation of nucleate boiling in zero gravity conditions

“…Finally, using Eqs. 7and (6) to express Eq. (5) and requiring it equals zero, a relation for the equilibrium radius R b is found:…”

“…On the other hand, things become much more complicated if microgravity conditions are searched. Most of the experiments in micro-gravity are carried out using drop towers, sounding rockets [5] or during parabolic flights [6,7]. However, the drawbacks of these methodologies are a short observation time and continuously varying gravity conditions.…”

Asymmetric interface temperature during vapor bubble growth

“…The thin film is 100 lm thick with an electrical resistance of 1.0 X and has a 50 lm triangular hole to create a unique artificial nucleation site where single vapor bubbles nucleate. More details regarding the test cell can be found in Serret et al 8 All experiments are carried out according to the same experimental procedure. At a constant mass flow rate and heat flux, we continuously acquire visible and infrared images.…”