Pre-registration, Version 2: A Regional Dimensionless Critical Heat Flux Model Against the 2006 Look-Up Table on Independent Near-Critical Data

Pre-registration of a second blind test of a dimensionless critical heat flux (CHF) model. A six-parameter Buckingham pi relation among the boiling number, density ratio, Weber number and equilibrium quality was selected by leave-one-source-out validation on the 2,553 rows of the NRC NUREG/KM-0011 CHF database with pressure of at least 14 MPa and mass flux of at most 1500 kg/(m2 s), under rules hashed before the first fit. It will be compared with the 2006 Groeneveld look-up table on the Oettig et al. (2026) measurements in a uniformly heated 15.8 mm, 7.1 m tube at 15.4 to 21.0 MPa (doi:10.14459/2025mp1839312), which neither method has seen. The hypothesis passes if the model's relative RMS error in series critical heat flux is lower than the table's. The document states everything that was seen of the test data before freezing. The archive contains the document and its source, all selection and test rules with their addenda, the training data, the selection and test code, the frozen model, the control and audit record, and SHA-256 checksums. Archive SHA-256: cc125d40bb68e543ca3102a27cc8dd7da1c148082ab775888af7c9d59dcd790b. The result will be posted as a new version of this record whichever way it falls.