Experimental study of critical heat flux in flow boiling under subatmospheric pressure in a vertical square channel

Nathan Colgan, Joseph L. Bottini, Raúl Martínez-Cuenca, Caleb Brooks

Research output: Contribution to journalArticle


Critical Heat Flux (CHF) is the maximal limit of heat flux in two-phase nucleate boiling heat transfer; therefore, an understanding of CHF under a wide range of conditions is important for safe system operation. In this work, CHF experiments are conducted over a range of subatmospheric system pressures in a vertical square channel that is heated on one side. The experimental conditions cover a pressure range of 20 kPa to 108 kPa, a mass flux range of 45–190 kg/m2-s, and an inlet subcooling range of 0–14 K. Heat flux is gradually increased until an excursion of the wall temperature occurs, indicating CHF. For the experimental conditions considered, CHF increases with rising system pressure, mass flux, and inlet subcooling, although the effects of mass flux and inlet subcooling are weak. A new correlation for CHF is developed and found to predict the data with an average error of ±15.6%.

Original languageEnglish (US)
Pages (from-to)514-522
Number of pages9
JournalInternational Journal of Heat and Mass Transfer
StatePublished - Mar 2019



  • Critical heat flux
  • Departure from nucleate boiling
  • Flow boiling
  • Subatmospheric pressure

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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