ID 433

Toward the Integration of Surrogate’s Thermophysical Properties in Primary Atomization Simulations

 

Abstract:

To accurately evaluate the thermodynamic state of the vapor and liquid phase of a multi-component fuel, properties can be derived from the constitutive pure species using the Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) by NIST. In the REFPROP program, the mixture model incorporates high-accuracy Helmholtz equations of state and mixing rules with estimated interaction parameters: compressibility, viscosity, surface tension coefficient, etc., are evaluated directly from the properties of the constituent pure fluids. Rather than from a static table, these properties can now be calculated at run time by the CLSVOF multiphase compressible code to investigate their effects on primary atomization, evaporation and cavitation phenomena. The novelty of this approach is that it does not require a new ad-hoc fitting of the equation of state if the fuel composition changes during the simulation; in fact, since the fuel composition is itself a variable, this approach could be used to study the effects of local concentration variations due to differential evaporation. The new capability is demonstrated in an ongoing simulation of primary atomization for spray G using the NREL’s 4-component blendstock for oxygenate blending composed by 55% iso-octane, 25% toluene, 15% n-heptane and 5% 1-hexene, by volume.