Investigation of the effect of flow swirl on heat transfer inside a cylindrical cavity

Experiments were conducted to determine local heat transfer coefficients on the inside surface of a cylindrical cavity that is cooled by a swirling air flow. Temperature sensitive liquid crystals were used as temperature sensors. Five blowing (cooling) modes were tested: three with swirl numbers of 0.36, 0.84, and 1.73, a fourth with no swirling component (axial flow) and a fifth which is similar to the fourth but has the flow direction reversed. Flow visualization and static pressure measurements were performed to improve understanding of the situation. The smoke-wire technique was successfully used to picture the flow patterns. Plots of local Nu number along the cavity surfaces were obtained for the five blowing modes and for three different Reynolds numbers.