Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 19, 2024 - November 20, 2024
Three-dimensional convective flow occurs in a single-sided heated rectangular channel depending on the heating temperatures. We investigated the structure and cause of the convective flow based on experiment and numerical analysis at different heating temperatures. In the experiment, a horizontal rectangular channel with controllable heating surface temperature was constructed and flow velocity was measured under multiple heating temperature conditions. Heating was applied only from the bottom surface, and flow velocities in the two-dimensional test section were measured using micrometer-resolution particle tracking velocimetry (micro-PTV). The result revealed the existence of three-dimensional convective flow with complex S-shaped velocity distributions in the spanwise direction of the channel and increased streamwise flow velocity near the heated bottom wall with the heating temperature. We attributed the three-dimensional convective flow to the buoyancy force caused by the density change of the working fluid due to heating from the sidewall surfaces. For verifying the deduction, numerical analysis was performed with the same geometry as in the experiment. In the analysis, the variations in density and viscosity were simulated with respect to temperature dependence. The analysis reproduced a rolled-up flow at sidewall surfaces when the temperature of the heating surface of the channel exterior was higher than that of the channel heating surface. In addition to these, we discuss the origin of the convective flow by considering different types of thermally induced flows including thermophoresis, Rayleigh-Bénard convection, and Marangoni convection.
