The effect of pulsating flow on forced convective heat transfer

The forced convective heat transfer in an annulus between two concentric circular cylinders within a pulsatile flow field was experimentally investigated. A specially developed wind tunnel, which had a facility for generating time dependent flows, was used for the experiment. The heaters used had an isothermal surface. The experimental tests were performed over a Reynold's number range from 100 to 2000 (laminar) based on the hydraulic diameter of the annulus and the velocity at maximum flow rate. The frequency of the pulsatile flow ranged from 0 to 40 hz. The partial differential equations for pulsatile flow in an annulus were also solved and the theoretical velocity field was generated and analyzed.;The experimental results show that there was significant increases in the Nusselt number over a range of non-dimensional frequencies compared to the steady flow analysis. In general, the data obtained indicated that the heat transfer is actually enhanced by about 25% at certain frequencies of the flow. The data also showed that the heat transfer starts to drop at higher frequencies compared to the steady flow results.