The Effect Of The Interfacial Force To The Condensation

A study on the effect of the interfacial force to the condensation is carried out in the present dissertation, as a frontier research subject being paid more attention with the progress of space material science and microgravity fluid hydrodynamics. The main content is as such:(1) We use Freon 12 as the object investigated in this part . In this paper, both physical model which include the condensation fluid film and mathematical model based on the boundary layer equation were founded and then transformed to a non-dimensional form by applying the similarity theory .This paper investigated the heat transfer process in the circular pipe and then analysed the effect of the gravity, the shearing force at the gas-liquid interface and the marangoni force caused by the surface tension on the heat transfer of the filmwise condensation and draw the curves in ORIGIN .The results showed that in microgravity the effect of the surface tension gradient on the condensed heat process can not be ignored . The greater the gradient was, the thinner the liquid film was; the bigger the Nusselt number was, the better the effect of the heat transfer was .(2) This paper investigated the heat transfer process in the circular pipe when the vapour with the additive. In this paper, both physical model which include the condensation fluid film and mathematical model based on the boundary layer equation were founded and then transformed to a non-dimensional form by applying the similarity theory. The effective additives trigger interfacial convection that leads to loss of hydrodynamic stability at the liquid/vapor interface and produce a spontaneous disturbance in the liquid condensate. As a result, condensation heat transfer is significantly increased.