Shock loss measurements in non-ideal supersonic flows of organic vapors.

This paper presents the first ever direct measurements of total pressure losses across shocks in supersonic flows of organic vapors in non-ideal conditions, so in the thermodynamic region close to the liquid-vapor saturation curve and the critical point where the ideal gas law is not applicable. Experiments were carried out with fluid siloxane MM (hexamethyldisiloxane, C H OSi ), commonly employed in medium-/high-temperature organic Rankine cycles (ORCs), in the (TROVA), a blowdown wind tunnel at the Laboratory of Compressible fluid dynamics for Renewable Energy Applications (CREA lab) of Politecnico di Milano. A total pressure probe was inserted in superheated MM vapor flow at Mach number with total conditions in the range and at varying levels of non-ideality, with a compressibility factor evaluated at total conditions between .