Effects of annular-cooler surface-roughness on wind resistance and thermal environment in a high-speed geotechnical centrifuge chamber

Abstract

Numerical simulations were performed to illustrate the influences effects of annular-cooler surface roughness on wind resistance and thermal environment in a high-speed centrifuge chamber, with the use of multi-reference-frame (MRF) method and classical roughness-modified model. In the present study, the absolute roughness height was specified in a range form 0.05 mm–2.5 mm. With respect to the clearance between rotating-arm tip and stationary-cooler surface, the relative roughness height was changed from 0.0014 to 0.07 accordingly. The results show that the flow field inside the centrifuge chamber is of highly three-dimensional feature. With the increase of surface roughness, the wind resistance is increased monotonously. With regard to the thermal environment, the maximum temperature inside the centrifuge chamber takes on a non-monotonous variation along with the surface roughness height, due to the two contrary influencing roles of surface roughness on the viscous dissipation heat generation and the heat removal capacity. In general, the use of roughed cooler-wall is a promising scheme for reducing the environmental temperature in a high-speed centrifuge chamber. Under the present research conditions, a more favorable relative roughness height is identified in term of a comprehensive factor that reflects the benefit of roughed surface on the reduction of maximum environmental temperature at the pay of aerodynamic penalty.

Keywords

• High-speed centrifuge
• Surface roughness
• Wind resistance
• Thermal environment
• Numerical simulation