Compressed air energy storage is one of the technologies required for the massive use of intermittent renewable energies, solar or wind. Liquid piston air compression increases the efficiency of energy storage by promoting intense heat exchange in the compression chamber.
However, the description and evaluation of this convective exchange for low bore / stroke ratio compression chambers is poorly studied in the scientific literature. Using an experimental study conducted on two test benches, the internal convective exchange in the compression chamber is studied. An inverse method, coupled with the measurement of the compressed air temperature and the position of the piston, is used to determine the instantaneous parietal thermal transfers during compressions. After having highlighted the systematic presence of a transition from the convective regime of laminar type to a turbulent regime in the volume of compressed air, new convective exchange correlations are sought. On the basis of 73 experiments, several forms of correlations based on dimensionless numbers are optimized and compared.
Two new Nusselt number correlations, one in a laminar regime and the other in a turbulent regime, are then selected. A 1D thermodynamic unsteady model of the compression chamber is then built in the Matlab / Simulink environment to test the quality of these correlations. The numerical results are thus compared with the experimental data. Finally, two additional experimental tests, carried out on a different test bench, make it possible to confirm the quality of the new convective exchange correlations proposed.
Stakeholders or Phd/Writer name
- Thibault Neu