A general correlation for critical heat flux in horizontal channels

•Presents a new thoroughly verified correlation for CHF in horizontal channels.•Verified for micro and macro tubes, multichannels, subcooled and saturated CHF.•Verified for extremely wide range of pressure, flow rate, diameters.

While horizontal channels are widely used in heat exchangers involving boiling, no well-verified method for predicting CHF (critical heat flux) in them is available. Presented here is a general correlation for CHF in horizontal channels. It provides the ratio of CHF in horizontal channels to CHF in vertical channels. It has been verified with a very wide range of test data that include 10 fluids (water, refrigerants, and hydrocarbons) in single channels and multi-channels of diameters 0.13–24.3 mm, reduced pressures from 0.005 to 0.9, mass flux from 20 to 11,390 kg/m2s, inlet qualities from −1.05 to 0.72, and critical qualities from −0.2 to 0.99. Data include uniform and non-uniform heat fluxes. With CHF for vertical channels calculated by the author's published correlation, it predicts 878 data points from 39 data sets from 18 sources with a mean absolute deviation of only 15.4%. The new correlation is presented and other predictive techniques are also discussed.