Coupled heat and mass transfer of oscillatory upward impingement jet: FSI application to anti-icing from a concave surface

Impingement of fluid and species is a subtle process in drying and anti-icing strategies. The present paper studies the convective heat and mass transfer of oscillating hot air jet impinging upward upon a semicircular cold surface, considering the uniformity of heat and mass transfer. A sinusoidal excitation is applied to the tips of the jet walls utilizing fluid-structure interaction scheme. The conservation equations of mass, energy, momentum and stress are discretized and solved by the Galerkin FE method, whereas the displaced elements that involve and surround the oscillated jet have been treated by the arbitrary Lagrangian-Eulerian scheme. Correlations for the Nusselt and Sherwood numbers have been established for specified ranges of buoyancy ratio, oscillation amplitude and jet-to-curved surface distance. Results show that the oscillating jet mitigates the stagnation regions on the curved surface, hence, reducing the thermal effort required to maintain a constant cold temperature. The heat transfer uniformity criterion demonstrates that, to achieve greater thermal uniformity, the jet oscillation amplitude should be widened, and the jet should be located farther from the concave surface. The oscillating distribution of species also yields encouraging results, as the jet's sweeping mechanism covers the entire span of the curved surface. Jet proximity to the curved surface improves heat and mass transfer; increasing jet upward offset spacing, Yc, from 0 to 2.5, enhances Nusselt and Sherwood numbers by approximately 9%.