A Numerical Procedure for Defogging Process （一个数值程序除雾过程）.pdfVIP

A Numerical Procedure for Defogging Process Simulation in Automotive Industry 1 1 2 1 G. CROCE , P. D’AGARO , F. MATTIELLO , A. DE ANGELIS , 1DiEM, Dipartimento di Energetica e Macchine Università di Udine, Via delle Scienze 208, 33100 ITALY 2 Centro Ricerche Fiat Orbassano (TO) ITALY Abstract: - A suite of routines for the prediction of environment moist condensation and evaporation on solid surfaces is presented. The physical problems requires the solution of the air flow field along a (cold) solid surface, the evaluation of the unsteady conduction through the solid itself, and the development of a suitable model for the heat and mass transfer through the thin water layer on the fogged surface. The routines for the unsteady simulation of the water layer evolution are designed as a purely interfacial procedure, minimising the exchange of information with both the flow and the conductive solver. This allows the coupling with different solvers. Here, the model is used in connection with a commercial CFD solver, in order to predict the defogging process of a car windshield. The water layer is modelled as a collection of closely packed tiny droplets, leaving a portion of dry area among them. The effect of the contact angle is taken into account, and physical assumptions allow to define the local ratio between wet and dry sur