Modelling of multi-component droplet evaporation under cryogenic conditions

The vaporization of drops of highly vaporizable liquids falling inside a cryogenic environment is far from being a trivial matter as it assumes harnessing specialized thermodynamics and physical equations. In this paper, a multi-component falling droplet evaporation model was developed for simulating the spray cooling process. The falling speed of the sprayed droplets was calculated with the momentum equations considering three forces (gravity, buoyancy and drag) applied to a droplet. To evaluate the mass and heat transfer between the sprayed droplet and the surrounding gas phase, a gaseous boundary film of sufficient thinness was assumed to envelope the droplet, while the Peng-Robinson equation of state was used for estimating the phase equilibrium properties on the droplet's surface. Based on the relevant conservation equations of mass and energy, the key properties (such as temperature, pressure and composition) of the liquid and gas phases in the tank during the spray process could be simulated. To conclude, the simulation algorithm is proposed.