Experimental mixed convection heat transfer from a large, vertical surface in a horizontal flow

The convective heat transfer from and the boundary layer flow on a vertical, 3-m-square surface parallel to a horizontal air flow were studied. The test conditions ranged from pure forced convection driven by a horizontal inertial force induced by the horizontal free-stream flow, to combined forced and free convection (i.e., mixed convection) driven by orthogonal forces, the horizontal inertial force and a vertical buoyant force generated by the heated vertical wall, to pure free convection driven by the vertical buoyant force. The emphasis of the study was on mixed convection. Surface temperatures and free-stream velocities renged from 40 to 600 C and 0 to 6.0 m/s, respectively, resulting in Reynolds numbers (Re) and Grashof numbers (Gr) up to 2 x 10/sup 6/ and 2 x 10/sup 12/, respectively. Convective heat-transfer and boundary-layer profiles of mean velocity, flow angle, and temperature were measured. The heat-transfer results showed the range of conditions for which the heat transfer was characterized either as forced, mixed, or free convection. Correlations for mixed-convection heat transfer and for variable properties free convection heat transfer were developed from the heat-transfer results. The combined effects of free-stream velocity, buoyancy, and variable properties on the location of the transition frommore » laminar to turbulent flow were also noted from the heat-transfer results. The boundary-layer profiles demonstrated the variation of mean velocity, flow angle, and temperature through the boundary layer for test conditions ranging from forced, to mixed, to free convection.« less