Essay On Blast Wave Generating Device

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The blast wave generating device developed for this project consists of two sections that are equivalent in cross sectional area to the expansion section channel of the shock tube; the front section has internal damper blades that rotate from a vertical position to a horizontal position, and the rear section is equipped with internal flow straighteners. The device is to be placed in series between the expansion section and the expansion section channel, and bolted together with the flanges of these two sections. The main operation of this device works by producing a shock wave from the bursting of a diaphragm from the driver section, which travels down the shock tube through the expansion section, and into the device. The wave hits the damper …show more content…
For simplicity the device was to be constructed in four parts and then these four parts were assembled. The four basic parts are: shell, slats, flow straighteners, and weight system. The shell serves as the outer steel walls to contain the shock wave, while at the same time providing a structure and frame for the slats and rods (which externally support the weight system). The rods that rotate with the slats also interface with the weight system which provides an opposing moment to resist rotation in order to delay the travel of the shock wave. Lastly, the shell serves as a structure to fasten the flow straighteners inside the posterior section of the device. The manufacturing of each of these four basic parts is further detailed in the following …show more content…
The shop worked with a tolerance of ± 0.01 inches, which is a standard machining tolerance. This tolerance was well within the limits as the exact size of the shell is not imperative; the most essential aspect of the shell was that it fitted to the existing shock tube expansion section.

The completed outer shell sections aligned with the existing flanges and holes in the expansion section correctly, and resulted in a secure assembly in the shock tube’s expansion section. On the side of the shell are the holes drilled for holding the slat rotation rods, the slat catchers, and the flow straighteners. The holes for the slat rotation rods were fitted with PVC rings cut from ½ inch schedule 40 PVC to serve as bearings for the rods, as well as keeping them centered, preventing jarring and the slats hitting the walls of the device, or each other. The PVC was fastened to the shell using JB Weld.

There was no redesign necessary for the shell after the initial tests showed the device did not work as expected. This was because the shell is simply the housing for the working parts of the device, and so the redesign was made to match these

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