ISSN Online: 2377-424X
International Heat Transfer Conference 4
THE INFLUENCE OF INTERNAL RADIATION EXCHANGE, ARBITRARY WALL HEAT GENERATION AND WALL HEAT CONDUCTION ON HEAT TRANSFER IN LAMINAR AND TURBULENT TUBE FLOWS
要約
A general formulation is presented for determining toe tube wall temperature distribution, gas temperature variation and local Nusselt number for gas flows in finite length circular tubes subjected to arbitrary wall heat generation. The effects of axial wall heat conduction, gas and/ or wall radiation are included in the analysis. Numerical results are obtained for a radiatively non-participating gas over a range of surface emissivity, wall conduction parameter and Reynolds number, including both laminar and turbulent flow. Uniform, sinusoidal and a step change in the axial variation of the wall heat generation, which is not equal to the a priori unknown heat conducted to the gas, are studied. Rather than approaching an asymptotic value, it is found that the Nusselt number decreases continuously and eventually can become negative for selected combinations of parameters.