The mitigation of pressure piling by divergent connections

Literature results show that the pressure piling phenomenon is the result of the combination of: (1) the precompression effect arising from the jet flow from the ignition vessel); (2) the turbulence induced by the fast flame propagation (jet ignition) in the secondary vessel; and (3) the vent flowing toward the ignition vessel, which mitigates the peak pressure. To control the severity of the explosion in the second vessel it is possible to either limit precompression or to reduce the characteristic ratio between the "reaction" and "venting" times. A mathematical model of the pressure piling phenomenon is proposed herein to study the possibility of reducing the peak pressure in the second vessel by limiting the turbulence level induced and thus increasing the reaction time with respect to the venting time. More precisely, the effect of geometry obtained by using divergent connection tubes from the ignition vessel to the second vessel and by varying the volume ratio between the two vessels has been evaluated, demonstrating that small modifications in the design will prevent the catastrophic behavior of pressure piling. © 2005 American Institute of Chemical Engineers