Écoulements transitoires dans les conduites déformables avec dégazage de l'air dissous

Transient flows in plastic pipes with dissolved air degasification

¹ Ecole Nationale d'Ingénieurs de Sfax, B.P. W, 3038 Sfax, Tunisie
² Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisie

Abstract

The dissolved air degasification in plastic pipe transient flows is studied with a numerical model. Degasification occurs when the pressure is below the saturation pressure given by Henry Law. Evolution of the little air bubbles is isothermal. Air and water masses give the mean mass of mixing. Fluid pressure is connected to the pipe section variations. This gives a system of two non linear hyperbolic differential equations solved with a conservative finite difference method. Results show that the degasification area is strongly connected to the wall elasticity and pressure remains slightly below saturation. The model appears reliable with regard to published experimental results.