Heat Transfer Of Water Under Supercritical Pressures In Vertical Upward Tubes

As the only type of water-cooled reactor among the six advanced nuclear energy systems proposed by the Generation-IV International Forum, Supercritical Water-Cooled Reactor (SCWR) has the prominent advantages of economy, continuity of experience, technology maturity and sustainability. It comes into an essential choice of development of high-power pressure water reactor technology. Among the fundamental topics and necessary basis of SCWR R&D, study on heat transfer characteristics of water at supercritical pressures has got great attention.In this thesis, according to test data, discussions on heat transfer model of water of supercritical pressures in vertical upward tubes, and the effects of various factors on heat transfer are performed. According to sharply change of thermal-physical properties near the pseudo-critical region, analysis on action of buoyancy and acceleration effects is conducted.In this thesis, available experimental data of forced convective heat transfer of supercritical water in vertical upward tubes are extensively collected to establish a wide-ranged data bank; based on analysis of mechanism of heat transfer and the form of correlation, two kinds of dimensionless number groups are introduced to reflect special influents on heat transfer which are induced by the drastic variation of supercritical water properties and related secondary effects. With Standard regression coefficient (SRC) and comparisons of error, sensitivity analysis is performed and the form of correlation is identified. Applying principal factor analysis, two types of wide-ranged heat transfer correlations are regressed through principal component analysis. The evaluation of prediction error shows that the two correlations arrive both wide-ranged and high accuracy and work well within heat transfer deterioration region.However, correlation is not enough for system analysis code for its relatively slow calculation efficient and iteration convergence. Therefore, look-up table is introduced to predict heat transfer behavior, which is easy to use and easy to update. Based on a correspond databank and study of regression model, two look-up table are established with discussion on test data groups, applying respond surface method (RSM). Meanwhile, based on the established look-up table, tube size effect on supercritical water heat transfer in vertical upward flow is preliminarily correlated and investigated. Further, assessments of the look-up table are carried out and delivered, and the errors are acceptable. With the increase of test data in various other practical engineered regimes, the look-up table is expected to be further improved.With the work of this thesis, experimental databanks of forced convective heat transfer of water in vertical upward tubes at supercritical pressures, as well as improvement of heat transfer research method, is constructed, which might lay a foundation for further comprehensive and intensive analysis.