Numerical comparison of conjugate and non-conjugate natural convection forinternally heated semi-circular pools

In this numerical investigation, a detailed comparison of the conjugate and non-conjugate natural convection within a semicylindrical cavity has been presented. The cavity is assumed to be filled with a fluid containing unifo rmly distributed internal heating sources. The bottom circular wall of the cavity is taken to be thick with finite conductive properties, while the to p wall is considered to be isothermal. The Navier-Stokes and energy equatio ns are solved numerically by using the SIMPLER algorithm. A Rayleigh number range from 3.2 x 10(6) to 3.2 x 10(11) has been investigated and the effec ts of solid-to-fluid conductivity ratios of 1.0, 5.0 and 23.0 have been ana lysed. The present numerical results for a semi-circular cavity with entire ly isothermal walls are compared with known results from the open literatur e. It was found that these results for the non-conjugate problem are in ver y good agreement. The present results for a conjugate cavity show a remarka ble difference from the non-conjugate analysis. The average Nusselt number for the solid-fluid interface shows a decrease while the top wall average N u number has increased. It has been concluded that these effects increase f or a system with a low solid-to-fluid conductivity ratio. It is evident fro m the present conjugate results that the assumption of isothermal enclosing walls gives somewhat different results when the walls are thick and the so lid-to-fluid conductivity ratio is small. (C) 2001 Elsevier Science Inc. Al l rights reserved.