VISUALIZATION OF CONVECTIVE INSTABILITY PHENOMENA IN THE ENTRANCE REGION OF A HORIZONTAL RECTANGULAR CHANNEL HEATED FROM BELOW AND/OR COOLED FROM ABOVE
Titel:
VISUALIZATION OF CONVECTIVE INSTABILITY PHENOMENA IN THE ENTRANCE REGION OF A HORIZONTAL RECTANGULAR CHANNEL HEATED FROM BELOW AND/OR COOLED FROM ABOVE
Auteur:
Cheng, K. C. Shi, Lei
Verschenen in:
Experimental heat transfer
Paginering:
Jaargang 7 (1994) nr. 3 pagina's 235-248
Jaar:
1994-07-01
Inhoud:
The developing secondary flow patterns caused by buoyancy forces in the simultaneous hydrodynamic and thermal entrance region of a horizontal rectangular channel (aspect ratio, a/b = 2) with isothermally heated lower wall and/or isothermally cooled upper wall are studied using the smoke injection method. The entrance air is at room temperature (around 23°C), and the temperature ranges for the lower and upper walls are 23-51°C and 15-23°C, respectively. The mean air velocities are 0.1, 0.2, 0.3, and 0.4 m/s. The Reynolds number varies from Re = 2.10 × 102 to 1.05 × 103 and the Grashof number ranges from Gr = 1.56 × 105 to 5.04 × 105. Photographic results reveal mixed convection, convective instability, and chaotic phenomena. Many new secondary flow patterns are revealed by this flow visualization study, and the photographic results should be useful for future theoretical study and measurements. The experiments were designed to understand flow physics.
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