Experiments on high-enthalpy water blowdown through a short converging nozzle were preformed to measure the critical discharge flowrate under different stagnation conditions. Two-phase critical flow models were reviewed and three of the simple predictive models were described. The test results were compared with the simple predictive models. It was found that the Henry-Fauske Model provided the best overall agreement with the experimental data. Photographic studies of the two-phase flashing jet revealed the presence of three distinct regions in the jet. These regions are consistent with the jet geometry proposed in previous studies.