Unstable direct contact condensation called ``Chugging'’ that occurs in certain conditions in the pressure suppression pool of Primary Containment Vessel of Boiling Water Reactors (BWRs) was studied experimentally. The mechanisms of every phase of the chugging was described, and experimental results useful for the development and validation of more accurate CFD models were provided. The experiment was conducted with a transparent pool and a transparent polycarbonate pipe or a stainless steel pipe with inner diameter of 27 mm under the conditions of the steam mass flux of 5.5–19.5 kg/m2s and the pool temperature of 19–46.5 °C. Pressure pulses were measured and synchronized with a high speed video camera for images acquisition. It was identified that the bubble implosion occurred while the pressure in the bubble quickly decreased. This condition might establish instability in the interfacial area which grew abruptly causing the implosion. Moreover the transparent apparatus allowed to interpret and relate internal condensations, generating pressure spikes of around 1.2 MPa because of the condensation-induced water hammer. Finally, the chugging condensation regime map was created from the experimental data.

Experimental study on steam chugging phenomenon in a vertical sparger

MEREU, RICCARDO
2017

Abstract

Unstable direct contact condensation called ``Chugging'’ that occurs in certain conditions in the pressure suppression pool of Primary Containment Vessel of Boiling Water Reactors (BWRs) was studied experimentally. The mechanisms of every phase of the chugging was described, and experimental results useful for the development and validation of more accurate CFD models were provided. The experiment was conducted with a transparent pool and a transparent polycarbonate pipe or a stainless steel pipe with inner diameter of 27 mm under the conditions of the steam mass flux of 5.5–19.5 kg/m2s and the pool temperature of 19–46.5 °C. Pressure pulses were measured and synchronized with a high speed video camera for images acquisition. It was identified that the bubble implosion occurred while the pressure in the bubble quickly decreased. This condition might establish instability in the interfacial area which grew abruptly causing the implosion. Moreover the transparent apparatus allowed to interpret and relate internal condensations, generating pressure spikes of around 1.2 MPa because of the condensation-induced water hammer. Finally, the chugging condensation regime map was created from the experimental data.
Bubble; BWR; Chugging; Condensation; Direct contact; Pressure spikes; Mechanical Engineering; Physics and Astronomy (all); Fluid Flow and Transfer Processes
File in questo prodotto:
File Dimensione Formato  
Experimental study on steam chugging phenomenon in a vertical sparger.pdf

accesso aperto

: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 1.87 MB
Formato Adobe PDF
1.87 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/1009642
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 39
  • ???jsp.display-item.citation.isi??? 30
social impact