Method of Predicting Pressure Profiles in Horizontal 37-Element Clusters

摘要

A new two-phase friction multiplier correlation has been developed to predict the pressure profile in two-phase flow with heat addition. The main difference from other pressure drop prediction routines is that in addition to the effect of quality, the effects of system pressure, heat and mass flux on the two-phase multiplier are included. The inception of two-phase flow is defined to occur at the onset of significant void in the subcooled boiling regime instead of the boundary between negative and positive thermodynamic equilibrium quality. Pressure drop data from an experiment with a fully segmented 6-metre long, 37-element fuel string were used to optimize the constants and exponents of this correlation for the friction multiplier. This pressure drop prediction technique was shown to successfully predict the measured pressure profiles. The more than one hundred overall pressure drop data were predicted with an RMS error of 5.4 percent. The pressure drop measured during experiments with geometrically different simulated fuel strings and different operating conditions were also successfully predicted. The paper presents the derivation of the equations in a systematic manner. The effects of the system parameters on the prediction error are discussed in detail. (Atomindex citation 16:042268)