Benchmark Validation Experiment of Plenum-to-Plenum Flow Through Heated Parallel Channels

This paper documents a computational fluid dynamics (CFD) validation benchmark experiment for flow through three parallel, heated channels from one plenum to another. The test section was installed into a facility designed for natural convection benchmark validation experiments. The focus of these experiments was the highly-coupled thermal-fluid dynamics that occur between mixing jets in the upper plenum of the wind tunnel. A thermal instability in mixing jets, called thermal striping, can cause damage to structures which is a concern for High Temperature Gas Reactors. Nine experimental cases were explored by varying the relative channel temperature or blower speed. The boundary conditions for CFD validation were measured and tabulated along with an uncertainty. Geometry measurements of the triple channel test section were used to make an as-built solid model for use in simulation. The outer tunnel and channel surface temperatures, the pressure drop across the test section, atmospheric conditions, and inflow into the upper plenum were measured or calculated for the boundary conditions. The air velocity and temperature were measured in the jet mixing region of the upper plenum as system response quantities.