Experimental and numerical investigation of dense gas fluid dynamics and BZT fluids exploitation for engery conversion applications (DSF.6573)

Research
Shock waves are strong pressure waves in a compressible medium produced for example by supersonic aircraft, explosions, lightning and other phenomena that create abrupt changes in pressure. Shock waves occur in a region if a disturbance takes place in a shorter time than the time required for sound waves to traverse that region. Although they are common in many industrial applications, they are not desirable because shock waves dissipate a considerable amount of energy. The purpose of the proposed research is to investigate whether, for some particular fluids expanding in the gaseous state at high pressure and temperature, shock waves can be avoided as opposed to what happens for common fluids like air and steam in similar conditions. Bethe, Zel'dovich and Thompson were the first scientists who theoretically predicted this phenomenon. For this reason, fluids exhibiting this non conventional behavior are called BZTs. Examples can be found within the hydrocarbons, fluorocarbons and silicon oils classes of substances.

Utilization
The proposed project features 2 main deliverables: 1) the experimental assessment of the possibility of avoiding the formation of shock waves in supersonic flows under particular conditions and for particular fluids called BZT and 2) a fluid dynamic code which would allow the investigation and design of processes in conditions that were previously difficult or impossible to model. An application for the mentioned discoveries is the Organic Rankine Cycle (ORC) turbine. ORC turbines are small to medium electric power plants similar to the steam cycle turbines used in big power plants but using an organic fluid in place of steam. Siloxanes are employed as working fluids for these turbines. An increase in efficiency is key to the marketability of these systems which are currently very costly.