Local turbulent opposing mixed convection heat transfer in inclined flat channel for unstably stratified airflow

Abstract

Local turbulent mixed convection heat transfer in inclined (from ϕ = 0° (horizontal position) till ϕ = 90° (vertical position)) flat channels for opposing flows was investigated for the case when only bottom wall is heated (unstably stratified flow conditions). Wide ranges of airflow parameters are covered: Re = 4 × 10 3–6.6 × 10 4, Gr q = 4.7 × 10 7–6.3 × 10 10, pressure p = 0.1; 0.2; 0.4; 0.7; 1.0 MPa. Correlation for calculation of heat transfer in inclined flat channels was suggested for the region without buoyancy instabilities. The experimental data were compared with the recent experimental data for inclined flat channels when upper wall is heated (stably stratified flow conditions).