Fuel injection System
Design
Final Design
Containment and Protection Structure
All
of the delivery system must be protected during testing to ensure durability
and reliability. In order to protect the
delivery system from the harsh heat and pressure present during successful
testing a protection cell must be built.
This protection box should be a cube with the approximate dimensions of
.5m x 1m x 1m. The top of this cube (one
of the 1m x 1m sides) will face the spray test cell and should have a .55 inch
hole drilled through at the center for the nozzle. The top of the box should have a slight slant
(~2°-3°) from one side to the opposite side.
On the low side of the slant should be a fluid collection grate. This is meant to act as a runoff system
should the experiment be done with an upward spray and with little or no
combustion taking place. This grate
should be connected with hose to a simple fill bottle which should be emptied
before every spray.
In order to ease access to the
delivery system the “bottom” of the box should be a 75 cm x 75 cm hinged door
with a positive latch. The hinges and
latch being used should be mounted in a manner that allows for a flat surface
on which the test cell can stand. A
second, smaller door (~25 cm x 25 cm) should be mounted in one of the sides for
further access.
The two most practical choices
for the box material are ½ inch aluminum plate and ¼ inch steel plate. The aluminum plate is preferable due to its
light weight, corrosion resistance, and ease of machining. Lining the inside of the protective box
should be a layer of sound deadening fire resistant foam of the kind used to
sound proof acoustic test rooms. In
conjunction with the aluminum box panels, this lining will help protect the
delivery system from the concussion made inside the explosives test room. A custom rubber fitting or high temp silicon
should be used such that it can act as a leak proof seal between the nozzle
pipe and the top of the protective box.
The spray test cell has been
determined to be a 2m x 1m x 1m rectangular cube with one of its 1m x 1m faces
meeting up with the 1m x 1m top of the protective box. It is into this volume that the fuel will be
sprayed and combustion should occur. In
order to protect the environment in which the tests are conducted a clear
plastic wrap is the placed around the test cell to contain the spray should
there fail to be a combustion. The frame
work needed to allow this plastic to be wrapped should consist of 1 inch square
steel tubing. One of the two 1m x 1m
sides should be beveled to match the 2°-3° slant on the top of the protective
box. This will keep the test cell
aligned with the central spray axis of the nozzle. On this same 1m x 1m square side there should
be drilled 8 holes which will accept through bolts which are to thread into
matching holes on the top of the protective box. The ability to detach these two parts will
greatly aid transportation.
It is important to catch the
non-combusted spray fuel if the experiment uses a downward or sideways spray
orientation. In order to contain the
fuel in the case of a downward spray there should be a collection tray
measuring 1m x 1m placed in the bottom of the test cell. Likewise, for a sideways spray a 2m x 1m tray
should be placed in the bottom of the test cell. The collection tray should be emptied after
every spray, with care taken to not come into contact with too much of the
fuel. The collection trays can be made
out of thin rolled aluminum with a 1cm – 2cm lip to aid in carrying tray and
pouring out any fuel.
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