A new model for studying the density wave instabilities of supercritical water flows in tubes

A new model is presented in this paper to study the density wave instabilities of supercritical water (SCW) flowing in tubes. A new regional partition of SCW is proposed in this model for better dealing with the great variations of physical properties of SCW in the neighborhood region of pseudo critical point, based on the analyses of the physical properties of SCW. According to the frequency domain method, the new model is employed to study the density wave instabilities of SCW flowing in tubes, and the calculation results are compared with the experimental data in literature, together with the calculation results of three previous models proposed by different researchers. According to the comparisons, the present model is proved to be more reasonable and accurate than the other three models. The relative error of the present model is less than 26%, while that of the other three models are all greater than 30%. Hence, it is believed that the present model can provide well guidance for the design and operation of supercritical boilers, steam generators and other relevant heat exchangers.