Modelling of pulsed air jet impingement heat transfer in a single-phase and gas-droplets mist jet

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

The flow structure and heat transfer of an intermittent impinging single-phase air and water mist jet with low mass fraction of droplets (not more than 1 %) is studied numerically. In the range of small distances between the tube edge and obstacle H/(2R) ≤ 6 in the pulsed jet heat transfer at stagnation point increases with a rise of pulse frequency, whereas at high distances H/(2R) > 8 frequency rise causes heat transfer reduction. Heat transfer intensity during flow pulse action increases and exceeds significantly the corresponding value for the stationary case. When there is no flow, the value of Nusselt number decreases considerably. Results obtained were compared with available data of other authors, and satisfactory agreement was obtained for the influence of pulse frequency on heat transfer of the gas jet with impinging surface.