Developing Flow Correlations for Different Valve Geometries Using Reference Media for R-744

Abstract

This paper presents experimental data of three different prototype valves with cone-, ball-, and slide-valve geometries that have been tested using R-744 and two reference media, ARAL 4005 and R-729, under one-phase flow conditions. Three different test rigs were used to carry out the tests using boundary conditions with the objective to achieve more or less similarity regarding the Reynolds number and the Mach number. One aim was to find physical-based flow correlations to describe the flow behavior of the three investigated valve geometries with carbon dioxide (R-744), hydrocarbon-based low-viscosity fluid (ARAL 4005), and air (R-729) as the fluid. The main goal of this research was to find a correlation between the flow coefficients of both (a) R-744 and ARAL 4005 and (b) R-744 and R-729 to enable the transfer of a flow coefficient measured for ARAL 4005 or R-729 into a flow coefficient for R-744.