Flow and heat transfer characteristics in an annulus wrapped with a helical wire

Convective heat transfer for an annulus, having its inner cylinder wrapped with a helical wire, has been numerically studied. Constant heat flux boundary condition is applied at the inner wall of the annulus whereas the outer wall is insulated. The computer code with k-omega SST turbulence model has been validated with the results of bare annulus. Several numerical results such as variations in velocity, pressure, vorticity, turbulent kinetic energy, temperature, friction factor and Nusselt number are presented for various annulus diameter ratios (D/d=1.5, 1.8 and 2.0), pitch ratios (P/d=9.09, 18.18 and 30.30), wire diameter ratios (Dw/d=0.15, 0.25 and 0.30) and Reynolds number (Re=20000 to 180000). The zones of possible hot-spots in the cusp region close to the wrap-wire are discerned.