Critical heat flux as a mass flux dependent phenomenon: Theoretical analysis, experimental confirmation and further CFD application


Critical heat flux as a mass flux dependent phenomenon: Theoretical analysis, experimental confirmation and further CFD application

Ding, W.; Geißler, T.; Krepper, E.; Hampel, U.

In this work, we report on a theoretical analysis and experimental investigations on critical heat flux (CHF) in subcooled flow boiling firstly. Commonly, CHF is considered as a local phenomenon. A validated CHF- concept recently developed in our group indicated that CHF may be initiated in two different ways, that is, locally and globally. We designed and conducted an experiment to verify this hypothesis. The experimental results agree well with the expectations from our CHF- modelling and confirm the two mechanisms. Following that, we continued to clarify the role of different parameters, such as channel orientation, channel length and hydraulic diameter. The new concept of CHF is useful to explain and predict CHF at conditions of low pressure and low fluid velocity. Further we applied this concept into an Euler-Euler computational multiphase fluid dynamics (CMFD) approach with wall boiling model which successfully predict the critical volume fraction under different conditions. The simulation results also had a good agreement with the corresponding experimental results.

Keywords: Critical heat flux; Boiling; CMFD

  • Invited lecture (Conferences)
    9th China-Korea Workshop on Nuclear Reactor Thermal-Hydraulics (WORTH-9), 15.-18.05.2019, Chongqing, China
  • Lecture (Conference)
    10th International Conference on Multiphase Flow, 19.-24.05.2019, Rio de Janeiro, Brazil

Permalink: https://www.hzdr.de/publications/Publ-29017
Publ.-Id: 29017