CRITICAL HEAT FLUX FOR FLOW BOILING OF WATER AT LOW PRESSURE IN VERTICAL INTERNALLY HEATED ANNULI

Paper in proceedings (conference paper)

en

The Critical heat flux (CHF) for flow boiling of water at low pressure described in this article is over the amount of experimental research and it is still not well described phenomenon. Flow boiling of a liquid is characterized by a high heat transfer from the heated surface into the fluid. However, the nucleate boiling regime is limited by the occurrence of the CHF leading to a possible thermal damage of the heated surface. This phenomenon may occur in a nuclear reactor accident in conditions during depressurization of the primary circuit and the loss of coolant. The article includes a comparison of correlations for low pressure and a description of the experimental loop built at the BUT. The testing loop will be designed as two coaxial tubes. The inner stainless tube will have an outer diameter of 9.1 mm and is internally heated by direct passage of direct current over a length of 700 mm. The external glass tubes of 12,6mm and 18mm inner diameter formed two different annular assemblies. The experimental parameters of outlet pressure and mass flux were varied in the ranges of 150–1500 kPa and 250–4000 kg/(m2 s)

critical heat flux, flow boiling, low pressures

2014-04-23

Brno University of Technology

Brno

978-80-214-4931-2

8th International Conference for Young Researchers and Ph.D. Students

1–5

5