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Indexed by:Journal Papers

Date of Publication:2016-06-01

Journal:INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

Included Journals:SCIE、EI

Volume:97

Page Number:130-145

ISSN No.:0017-9310

Key Words:Multi-component fuel; Quasi-dimensional vaporization model; Forced convection; Finite thermal conductivity; Finite mass diffusivity

Abstract:A new quasi-dimensional multi-component vaporization model considering the finite thermal conductivity and mass diffusivity within the droplet was constructed. First, the heat flux of conduction, enthalpy diffusion, and radiation absorption in the gas phase were calculated based on the Fourier's law, a multi-diffusion sub-model, and a simplified analytical solution, respectively. The phase equilibrium at the gas-liquid interface was calculated by the ideal and real gas approaches according to the ambient pressure. For the liquid phase, the assumption of the quadratic polynomial distributions of the temperature and component concentration within the droplet was proposed in the quasi-dimensional model. Then, the proposed vaporization model was extensively validated by the experimental measurements, and good agreements were observed. Based on the computational results, the vaporization and movement behaviors of fuel droplets under forced convection conditions were further understood. Finally, by comparing with the zero-dimensional vaporization model with uniform temperature and component concentration distributions within the droplet and the one-dimensional vaporization model with finite thermal conductivity and mass diffusivity in the radical direction of the droplet, it is found that the quasi-dimensional model agrees better with the one-dimensional model than the zero-dimensional model, especially for the conditions with high ambient temperature and velocity. Sensitivity analysis indicates that the temperature gradient within the droplet plays a significantly important role in the droplet vaporization process. (C) 2016 Elsevier Ltd. All rights reserved.