Simulation of a Radial Pump Fast Startup and Analysis of the Loop Response Using a Transient 1D Mean Stream Line Based Model

Laura Matteo,Antoine Dazin,Nicolas Tauveron,Gédéon Mauger

doi:10.3390/ijtpp4040038

Abstract

A predictive transient two-phase flow rotodynamic pump model has been developed in the Code for Analysis of THermalhydraulics during an Accident of Reactor and safety Evaluation (CATHARE-3). Flow inside parts of the pump (suction, impeller, diffuser and volute) is computed according to a one-dimensional discretisation following a mean flow path. Transient governing equations of the model are solved using an implicit resolution method and integrated along the curvilinear abscissa of the element. This model has been previously qualified at the component scale by comparison to an existing experimental database. The present study aims at extending the validation at the system scale: a whole experimental test loop is modelled. The ability of the transient pump model to predict flow rate, head and torque as a function of time during a 1-s pump fast start-up is evaluated. The transient evolution of the pressure upstream and downstream from the centrifugal pump is well predicted by the simulation compared to the measurements. Local quantities such as pressure and velocity inside elements of the circuit are analysed. In the considered case, inertial effects of the global circuit are dominant when compared to pump inertial effects due to the high characteristic lengths of the pipes. The main perspective of this work consists in the simulation of similar pump transients, in cavitating conditions.

Highlights

Hydraulic systems containing rotodynamic pumps often involve complex flow transients, especially in the context of nuclear power plant safety evaluations where accidental scenarios are investigated (Chenaud et al [1])
The prediction of steady performance curves of the DERAP centrifugal pump using the developed model is presented in the following
This paper presents a whole loop modelled with the CATHARE-3 thermal-hydraulic code

Summary

Introduction

Hydraulic systems containing rotodynamic pumps often involve complex flow transients, especially in the context of nuclear power plant safety evaluations where accidental scenarios are investigated (Chenaud et al [1]). The purpose of the present paper is to develop a predictive rotodynamic pump model to be integrated in a thermal-hydraulic system simulation computational code. The corresponding scientific system scale software is the Code for Analysis of THermalhydraulics during an Accident of Reactor and safety Evaluation (CATHARE-3), which is used as a reference for nuclear safety analyses.

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Conclusion