Gaseous Detonation in Piping Systems Partially Filled With Liquid

Abstract

In this paper, we report the results of our investigation into the transmission of a detonation from a gas-filled section of pipe into a water-filled portion. Experimental studies were performed using a detonation in a H2-N2O mixture within a 2-inch, Schedule 40 pipe. The detonation wave impinges on a vertical column of water just downstream of a 90-degree bend. A shock wave is transmitted into the water-filled section and propagates slower than the sound speed in the water due to the coupling of flexural waves in the pipe with pressure waves in the liquid. Incident, transmitted, and reflected pressures in the gas are monitored, along with hoop and longitudinal strain throughout the pipe length. Results are presented for a both prompt initiation of an ideal (Chapman-Jouguet) detonation and deflagration-to-detonation transition (DDT) occurring just upstream of the gas-liquid interface. The results of the experiments are analyzed using computational modeling and simulation with an Eulerian hydrodynamic code as well as classical wave interaction methods. For a Chapman-Jouguet (CJ) detonation, the reflected and transmitted pressures agree with the classical one-dimensional theory of wave interaction. The values of the peak reflected pressure are close to those that would be obtained considering the water as a perfectly reflecting boundary. The transmitted wave propagates at a speed consistent with the Korteweg speed of classical water hammer theory and little to no attenuation in amplitude over ∼ 1.5 m of travel. In one DDT event, peak pressures up to 11 times the CJ pressure were observed at the end of the water-filled section.

Detonation and Transition to Detonation in Partially Water-Filled Pipes

“…ward (frames [4][5][6]. In frames 7-8, the two wall shocks cross and merge to form a single, horseshoe-shaped, expanding shock wave which decreases in strength as it expands.…”

“…Detonations in piping systems featuring vertical columns of water have been investigated both experimentally and computationally [5]. However, because the water column is vertical, the interaction between the detonation wave and the liquid is confined to a single location.…”