Analyses of subcritical and supercritical vapor explosions using thermal detonation wave theory.

摘要

The shock adiabatic model is a thermodynamic model originally proposed to simulate the vapor explosion phenomenon, assuming a steady-state shock wave traveling in a one-dimensional homogeneous medium. This model is based on the analogy between the chemical detonation and the thermal detonation, which has the benefit of predicting the shock pressure and the propagation velocity without detailed knowledge of the kinetics of fuel-coolant mixing and the energy transfer rate. The predicted values of the pressure and work output by this model, however, are upper bounds.; The shock adiabatic model has been modified by relaxing the condition of the complete fragmentation of the fuel and total energy transfer from the fuel to the coolant in the explosion. A new methodology was adopted using known values of the shock pressure and propagation velocity for the estimate of the initial mixing conditions of the experiment, the fragmented fuel mass in the explosion, and the work output. In this work, steady state analyses of subcritical and supercritical vapor explosions have been carried out using the modified shock adiabatic model. The KROTOS experiments, conducted at the Joint Research Center at Ispra, Italy, were used as our benchmark experiments in the analyses. Using this new model, we have compared various possible closure relations applied to the detonation wave theory for a vapor explosion at a given detonation state (CJ point) for an experiment. The results of such analyses have shown reasonable agreement with the experiments.; Mechanistic model analyses have also been carried out using the TEXAS model, a transient, one-dimensional model with two Eulerian fields and one Lagrangian field. This model has been modified and enhanced by implementing real equations of state for coolant using the NBS-water EOS package. A comparison was made between the modified thermodynamic model results and the TEXAS mechanistic model results.