heat and mass transfer
thin film cooling method
cooling agent’s mass discharge
cooling agent’s evaporation
A complex nonlinear heat and mass transfer during bodies cooling by liquids is analyzed. The liquid cooling agents having dynamic viscosity decreasing to three-five orders in relation to temperature rising to 150-200 degrees is considered. The mentioned above cooling agents properties make the automated cooling agent admission system’s design possible using the specially organized pore system in nose parts of hypersonic flying vehicles, so that the surface mass loss is eliminated due to surface temperature conserving below cooling agent evaporation’s temperature. This method can be applied to the nose surface geometry’s conserving during vehicle recapturing.
The described heat effect is organized by convection output on internal body’s surface, by filtration in organized pore system, by thin liquid film on the external body’s surface and principally by thin liquid film evaporation and cooling agent steam blowing into high-temperature boundary gas flow.
The complex mathematical model is combined from next particular models: convective heat exchange on internal body’s surface contacting with cooling agent; heat conduction considering filtration effect; nonlinear and non-isothermal liquid’s filtration throw the organized pore system; liquid thin film flow on external surface; liquid’s evaporation and steam blowing into the boundary gas flow; coupled heat exchange between liquid thin film and cooled body.
Mathematical model of cooling agent’s filtration is based on nonlinear filtration law considering inertia of liquid flow in canals, so that the Darcy law no considers. The solution is found analytically, the heat conduction problem’s analytic solution is found approximately. The obtained results show that the cooling agent’s mass discharge is around , the temperature of the full thermodynamic system is near to the cooling agent’s boiling point and the structure operates without surface mass loss, so that the proposed cooling method for hypersonic vehicles nose parts is possible.