xRage: HE initiation models

The xRage code contains three HE ignition models: Forest Fire, Cerro Grande and Ignition and Growth. After describing these models we present results of verification and validation (V and V) tests. These include simulations to determine the Pop-plot for each model and comparision with embedded velocity gauge data for shock-to-detonation transition (SDT) experiments. The data for the SDT experiments on PBX 9502 is taken from the recently developed high explosive database (HED). The HED data files contains additional meta-data with the key experimental parameters. This enables the use of scripts to automate testing: generating xRage input file, running simulation and generating comparison plots with experimental and simulated data. The simulations show that the models are robust. But there is a mesh dependence with the time for transition-to-detonation varying by several tenths of microseconds. After the transition to a detonation wave, the detonation speed and pressure may vary by a few per cent.