Mixed convection in laminar/turbulent separated backward-facing step flows

<p>"Mixed convective heat transfer results for two-dimensional laminar/turbulent flow in a duct with a backward-facing step are reported. The two walls forming the duct are maintained at uniform but different temperatures. The straight wall is maintained at the inlet air temperature, while the downstream section of the stepped wall is heated to a higher temperature. This study focuses on a backward-facing step geometry with an expansion ratio of two. The present laminar study examines a wide range of inlet flow and wall temperature conditions to cover the domain from buoyancy-assisting mixed convective flow, pure forced convective flow, buoyancy-opposing mixed convective flow to the inlet starved convective flow. Turbulent mixed convective flow is numerically simulated by using a modified k - ε model. For the buoyancy-assisting laminar flow, the buoyancy force reduces the pressure drop across the duct along with the reattachment length and increases the heat transfer rate. The reverse of previous trend applies for the buoyancy-opposing flow condition. A larger buoyancy force in buoyancy-assisting turbulent flow will decrease turbulent kinetic energy, increase the dissipation rate of turbulent kinetic energy, thus causing reattachment length to increase and the heat transfer rate to decrease. The numerical predictions are compared very favorably with existing, but limited, experimental and numerical data"--Abstract, page iv.</p>

Name thesis:degree_name

Ph. D. in Nuclear Engineering

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Lin, Jen-Tai

• Nuclear Engineering

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/721

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1723