Analysis of Basic Phenomena in Boiling Channel Instabilities With Different Flow Models and Numerical Schemes

Abstract

The results of a computational study on boiling channel stability are here discussed. The study compares the information obtained by two programs, developed in previous work for the linear and the nonlinear stability analysis of boiling channels basing on a simplified flow model, with the predictions of a well known system code. The phenomena highlighted by the results of the system code, adopted with different flow models and numerical methods, are discussed in a systematic way with the aid of the description obtained by the simplified model, in order to obtain a clearer picture than could be achieved by the mere application of the system code to conditions of interest for boiling water reactor stability. The effects on the obtained results of non-equilibrium, numerical discretization and number of nodes are considered, evaluating their influence on the predicted stability boundaries. Some physical aspects of the density-wave mode of instability are finally discussed basing on the predictions obtained by the different models.

Determining potential of subcooling to attenuate hydrodynamic instabilities for steam–water two phase flow

“…The phenomenon of temperature fluctuations damping in water associated with the effect of turbulence was discussed by Van Meulenbroek and Van de Wakker [25]. Boiling channel stability was investigated by Ambrosini and Ferreri [26], they concluded by their experimental and theoretical study that unstable boiling channel is a non-linear oscillator and its frequency was determined by the mass of the fluid and constant pressure drop. Strubelj and Tiselj [27] simulated the condensation induced water hammer.…”

Analysis of Density Wave Oscillations in Helically Coiled Tube Once-Through Steam Generator

“…It is well known that the RELAP5 code is usually considered for bestestimate transient simulation of thermal hydraulic phenomena relevant for light water reactor applications. The ability of RELAP5 to analyze DWO has been confirmed in many works of literature [3,16,17]. RELAP5 and STFQH have respective advantages to analyze DWO in H-OTSG.…”

Numerical and experimental investigations on the physical characteristics of supersonic steam jet induced hydrodynamic instabilities

“…[6] The modeling of the initial laminar flows from the nozzles of the regular and irregular crosssections using large-eddy simulation have been performed. The thermal hydraulic instabilities in boiling channels have been investigated [8] by using RELAP5 code. The thermal hydraulic instabilities in boiling channels have been investigated [8] by using RELAP5 code.…”

“…[7] The large-eddy simulation-based model has been validated by comparing the predicted entrainment rates with those already published in the cited literature. The thermal hydraulic instabilities in boiling channels have been investigated [8] by using RELAP5 code. An experimental and numerical study of the rectangular slot-burners widely used on power stations in Victoria has been performed, [9] the numerical results were validated against the experimental results, and then visualization of the developing flow field was used to reveal the final details of the cross-flow/burner jet interaction, based on this study, it has been found that the agreement between numerical and experimental jet features was quite good.…”