Fully-developed turbulent flow for the inner side in "TWISTED TUBES" with different cross sections geometries are experimentally and numerically investigated in the case of constant wall temperature. Two different geometries are considered. The tubes are helically twisted along the axis perpendicular to their cross-section .The helical twist geometry is described by the 360◦ twist. The results are comparing with tube without twisting "SMOOTH TUBE" in order to point out the heat transfer enhancement and the friction factor increase in the turbulent flow field . Numerical simulations are performed for three - dimensional and fully – developed flow by using RNG k-ɛ turbulence model. Both experimental and numerical results show that the enhancement in the heat transfer decrease as the Reynolds number increase and the values of friction factor decrease as the Reynolds number increase.

Fully-developed turbulent flow for the inner side in "TWISTED TUBES" with different cross sections geometries are experimentally and numerically investigated in the case of constant wall temperature. Two different geometries are considered. The tubes are helically twisted along the axis perpend...