Critical initial conditions for spontaneous thermal ignition

Critical initial conditions for thermal ignition are calculated numerically for planar, cylindrical and spherical geometries. In each case a compariso n is made on the bifurcation diagram with the intermediate steady state(s). It is clearly seen that the actual critical initial condition which depend s upon the initial temperature profile, is partly below the intermediate st eady state(s). The variation with ambient temperature, exothermicity and Bl ot number are all explicitly shown. The results are important for calculati ons relevant to the critical hot product assembly problem where a hot manuf actured organic product is packed into containers or stockpiled at a subcri tical ambient storage temperature. An example calculation for an interestin g case study (milk powder) is given to illustrate the utility of our result s.