Studies on Fluid-to-Fluid Modeling of Critical Heat Flux in a Helically-Coiled Tube
An experimental study on critical heat flux (CHF) in a helically-coiled tube cooled with R-134a has been completed in order to assess present fluid-to-fluid modeling approaches. The investigated range of flow parameters for R-134a was: pressure from 0.2 to 0.5 MPa, mass flux values from 50 to 1500 kg m-2 s-1 and inlet quality from -0.2 to 0.1. The CHF data of R-134a have been compared with that of water by applying the Ahmad and the Katto modeling. The water equivalent CHF data translated from R-134a CHF data by using the two modeling approaches have shown a good agreement with the actual water CHF data from previous studies when mass flux exceeds 600 kg m-2 s-1. The results indicate that both the Ahmad and the Katto modeling can be applied only for the high mass flux conditions in helically-coiled tubes.
L. Z. Tan et al., "Studies on Fluid-to-Fluid Modeling of Critical Heat Flux in a Helically-Coiled Tube", Advanced Materials Research, Vols. 588-589, pp. 1777-1780, 2012