Heat transfer and evaporation processes from the Enskog-Vlasov equation and its moment equations




Struchtrup, Henning
Jahandideh, Hamidreza
Couteau, Arthur
Frezzotti, Aldo

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Nonequilibrium heat and mass transfer processes through liquid-vapor interfaces are studied through solutions of the Enskog-Vlasov (EV) and the corresponding system of EV26 moment equations. These models fully resolve liquid and vapor bulk regions and the diffuse interface connecting both. With that, evaporation and heat transfer processes can be studied without the need of modelled interface relations. Comparison of numerical results shows qualitative agreement of moment simulations with DSMC solutions of the EV equation, but quantitative differences. Interface resistivities for jump interface conditions are determined from the simulations, which show marked differences to those found from classical kinetic theory, where dimensionless resistivities are constants. In contrast, the EV models give temperature dependent resistivities, some negative off-diagonal resistivities, and indicate non-linear behavior where resistivities depend on mass and heat fluxes through the interface. In summary, the results point to the urgent need for systematic evaluation of resistivities over a wide range of conditions between weak and strong nonequilibrium, close to and far from the critical point.



Enskog-Vlasov equation, liquid-vapor interface, evaporation and condensation, nonequilibrium, moment equations