Abstract
Vapour condensation in the presence of noncondensable gases in a high-pressure horizontal tube is targeted for heat exchangers of UUV system. The theoretical model of film-wise condensation, heat and mass transfer analogy, and several potential key factors are reviewed. A numerical model and experimental validation are then conducted. The results show that the numerical prediction is in good agreement with experimental results. Based on the established numerical model, the heat and mass transfer mechanism under the pressure of 10 MPa, characterised by a UUV heat exchanger is investigated. The study case shows that the fluid database can provide more accurate results than the existing real gas model since more non-ideal fluid properties are included. The vapour partial pressure can be decisive since the deviation of 4∼5% can result in a discrepancy of 47.4–51.6% in the ability of vapour latent heat recovery. High pressure conditions present a strong adverse impact on the mass diffusivity, but the effect is not sufficiently reflected in the suppression of condensation heat transfer coefficient. In a UUV heat exchanger, a reasonable high pressure in the outer loop is beneficial to increase the heat transfer performance since it can give rise to a higher bulk saturated temperature and more leeway for setting the subcooling degree, by which the two-phase flow can be sufficiently overlapped with each other to reduce the total thermal resistance. This work provides an insight into the potential application of the heat transfer mechanism of vapour condensation in the presence of noncondensable gas in a horizontal tube.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call