Explosively driven imploding pump tube showing (a) pump tube before detonation, (b) ideal pump tube operation, (c) initial stages of operation, (d) nonideal operation, and (e) tamped operation.
Experimental set-up for investigation of the precursor shock wave in an imploding tube. (a) Driver experimental setup with instrumentation and (b) typical driver cross-sections.
(Color online) Photographs of recovered 0.64 cm OD pump tubes. (a) Pump tube cross sections taken 15 cm from the initial collapse point, (b) recovered pump tubes showing rupturing along the length, and (c) recovered length of the pump tube tends to decrease with increasing initial fill pressure.
Typical results for a 1.27 cm OD tamped pump tube with 20 atm initial fill pressure. (a) Detonation and PSW trajectories, (b) PSW velocity versus PSW position, and (c) standoff versus PSW position.
Summary of results with a 0.64 cm OD pump tube and corresponding model results, showing (a) the PSW standoff from the detonation front and (b) the PSW velocity, both measured 115 diameters after the initial collapse point.
Summary of results with a 1.27 cm OD pump tube and corresponding model results, showing (a) the PSW standoff for the tamped series, (b) the PSW velocity for the tamped series, (c) the PSW standoff for the untamped series, and (d) the PSW velocity for the untamped series, all measured 115 diameters after the initial collapse point.
Experimental measurement of the VOD of liquid nitromethane in tamped pump tube experiments.
Force balance on a pump tube segment.
(a) Position-time graph showing the expanding pump tube and acoustic reverberations. (b) Zoom of the position-time graph of the expanding tube showing one time-step.
Expansion histories for (a) untamped and (b) tamped pump tubes.
(a) Dividing the length of tube exposed to PSW pressure into discrete slices, (b) exposed slices expand due to internal pressure, and (c) advancing Δt and re-dividing the length of tube exposed to PSW pressure into slices.
Parameter map showing regions of expected behavior when varying the initial fill pressure and explosive layer thickness for a 1 m long, 1.27 cm OD, 1.09 cm ID pump tube. In the untamped case, the outer tube is a 3.18 cm thick PETG tube, for the tamped case it is a 1.27 cm thick steel tube. (1) Untamped pump tube does not fail, (2) Tamped pump tube does not fail, (3) tamper ineffective (tamper fails), (4) tamper ineffective (tamper too far from pump tube), (5) untamped pump tube does not collapse completely, and (6) tamped pump tube does not collapse completely.
Experimental details for all shot series.
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