Analysis of natural convection flow and heat transfer in a non-uniform heated vertical open channel

An experimental investigation on natural convection in a vertical open channel is carried out in order to investigate the effect of the non-uniformity of the wall heat flux distribution on the heat transfer and fluid flow behaviour. Particular attention is drawn to the effects of a periodical distribution of discrete heat sources on the characteristic quantities and the kinematic structure of the flow. The experimental evidences show that there are several flow mechanisms involved at different scales that induce larger rates of turbulence production and mixing in the near-wall regions, thus improving the wall heat transfer rates. Moreover, for the same injected wall heat flux, the thermal buoyancy induced flow rate enhances by 18% for the periodically heated configurations. This result is of particular interest in view of generation of useful heat for building purposes.