Experimental analysis of asymmetrical isoflux channel-chimney systems

Air natural convection in an asymmetrically heated channel with unheated extensions has been investigated experimentally. Local and maximum wall temperatures and heat transfer coefficients are presented, for different values of the process parameters. Optimal configurations in terms of the minimum values of maximum wall temperatures are obtained. Average Nusselt numbers and maximum dimensionless wall temperatures are correlated to the Rayleigh number and to the geometrical dimensionless parameters in the 10–1.5×105 range of the Rayleigh number times the expansion ratio. The addition of downstream unheated extensions improves the thermal performance of the channel for some configurations, the longer the extension and the lower the aspect ratio the lower the wall temperature in the channel.