Novel viscosity determination method: Validation and application to fuel flow

The kinematic viscosity is a major physical property to be used in numerical, experimental and analytical work in all the related fields of fluid flow research. Its determination can be based on experiments with viscometer and on calculations for single or multi-species components, possibly through the use of mixture law and other intermediate parameters. Its experimental estimation for multi-species and/or supercritical hydrocarbon mixtures under high temperature and pressure remains quite absent. The novel approach proposed in this paper is based on fluid permeation through characterized porous media. The Darcian law or the Darcy-Forchheimer equation are used depending on the flow regime. First tests have been realized with pure gaseous nitrogen at ambient then hot temperature (1200 K) for several varying pressures (up to 60 bar). The accuracy of the methods can be as low as 5 % by comparison to National Institute of Standards and Technology data. The main source of uncertainty is found to be linked to the characteristics of sensors. The method has been applied to liquid dodecane (from 300 K to 700 K and up to 60 bar) with the same order of accuracy before testing it on supercritical n-dodecane (658 K to 700 K up to 60 bar) for which no validation data have been found. By comparisons with computations for multi-species mixture, even multi-phase, a reasonable agreement is found. The novel viscosity determination technique opens a new field of fluid characterization in extreme operating conditions.