Underexpanded jets generated by high-pressure hydrogen leakage develop complex shock wave structures in the near-field region
making the conventional low-pressure jet integral model inapplicable for underexpanded jets. While notional nozzle models are usually used to provide equivalent boundary conditions for the integral model
the performance of combining different notional nozzle models with the integral model needs to be evaluated. This study combines several commonly used notional nozzle models with the integral model
and evaluates the calculation accuracy based on experimental data. The results show that the predictions agree well with the experimental data for the notional nozzle models that do not assume momentum conservation. However
for the notional nozzle models conserving momentum
the predicted nozzle exit mass flux
velocity and centerline concentration decay rate are larger
resulting in a significant deviation from the experimental data.
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