The main scientific objectives are directed to studies of the coupling phenomena involving hydrodynamics in highly compressible supercritical fluids and forced piston effect. After the implementation of a series of experiments on board the MIR station in the ALICE facility, evidence of continuing such a research program on the ISS became clear and was prioritised at the program management level.

In the DECLIC program the first scientific objective is dedicated to the direct visualisation of the boiling crisis and to the phase separation at very low volume fraction. Preliminary observations of critical density fluctuations in the direct space are also expected. These density fluctuations have natural length scales as the correlation length which value is around 0.5µm, and time scale 12ms for temperature fluctuation of ± 1mk around the critical point. Simultaneously, typical runs are dedicated to the boiling study. For this latter topic, a specific cell with internal heater is designed in order to control the heat flux delivered to the gas bubble, in the two phase domain T Tc.

This High Temperature Insert is dedicated to the Study of Forced Piston Effect in H₂O and coupling phenomena between chemical reactions and hydrodynamic in highly compressible supercritical fluids.

The scientific objectives are : study of the heat and mass transfer in near-critical water submitted to a pulse heating and/or mechanical quenching, with observation of the critical behavior of water.

The experiment will necessitate critical temperature (Tc) search and equilibration steps with measurement of temperature and density gradient relaxation.

This experiment has led to the study of new technological problems linked to high temperature and high pressure utilization.

The design is performed to withstand temperature up to 600°C and high pressure up to 500 bars. The sample cell body and the corresponding optical windows are submitted to an agressive environment that must to be under control. Recent achievements have evidenced the technical difficulties in this high temperature, high pressure experimental cell, observed through a wide transmission diameter (around 12mm), designed taking into account a reduced volume and NASA safety constraints.

The DECLIC solidification program on board the ISS is targeting both Fundamental Physics and Materials Processing.

Basic Fundamental Physics is related to :

Self organization in far/from-equilibrium systems
Growth and Patterns in Non-linear Physics
Dynamics of extended 3D-systems

Materials Processing with active control is related to :

Microstructure engineering for specific in-use properties of materials
Well-defined model experiments on technical alloys, and on model transparent systems to be achieved with the DECLIC facility.
Physical modeling and numerical simulation at the microstructure and fluid flow scales.
Comparative studies involving microgravity benchmarks under diffusion transport and 1g-experiments effected by fluid flow caused by earth gravity.

The Directional Solidification experiment is performed in a dedicated insert, which ensures dedicated conditioning of sample material encapsulated in a cartridge.

The succinonitrile-based alloy utilization has led the designers to take into account the safety aspects that were considered as critical due to toxicity of the sample in certain conditions.

Main scientific objectives :

Birth of Morphological Instabilities

Dynamics of formation and Selection of Cellular/Dendritic Array
Recoil of the Front in Initial Solidification Transient

Coupling effects between Solidification Front and Convection.