LLC, a manufacturer of Ultrasonic Additive Manufacturing (UAM) solutions,
headquartered in Columbus, Ohio, USA, has partnered with Luna
Innovations, Roanoke, Virginia, USA, a manufacturer of medical,
telecommunications, energy and defence technologies, to gather data in
cryogenic fuel pipes for rocket test stands at NASA Stennis Space Center for a
goal is to collect data on pressure and temperature gradients inside of its
fuel piping closer to the test article to better understand how a particular
engine is behaving. Historically, NASA has mounted
sensors to the outside of pipes using elbows and ports, which communicates some
data. However, these do not give the same fidelity as sensors located adjacent
to the fuel stream and can disrupt the fuel stream. Similarly, NASA has mounted
sensors directly into the flow path using pass-throughs in the existing pipe.
These ports and pass-throughs can, however, influence the fuel flow, adding
uncertainty to the measurements.
to Fabrisonic, the team assigned to this project additively manufactured
sensors directly into the wall of the pipe. This allows a suite of sensors to
be embedded in essentially the same space, giving a clearer picture of thermal
and pressure gradients in the piping since no ports are required. All of the
sensors used were fibre optic based sensors, provided by Luna Innovations. The
team selected fibre optic sensors as they are small and thus don’t create a
large impact on the structure of the pipe. The fibre-based sensors can also
collect data over the entire length of the fibre allowing for a continuous
length of sensing instead of a fixed point.
company states that, as with many projects, Fabrisonic chose to only additively
manufacture a portion of the pipe as AM is expensive and the team worked to
minimise the amount of AM. The team started with an existing pipe and a flat
section was milled into the outer diameter (OD) of the pipe creating a landing strip for embedding.
A small groove was cut to positively locate each fibre and
once the fibres were inserted
by hand, Fabrisonic additively manufactured additional material over the
landing strip to build the OD back up to specification. After the AM process,
excess material was removed using standard CNC milling.
team has reportedly tested the pipe at various pressures and temperatures to
calibrate the sensor. This included boiling the pipe in water and filling it
with liquid nitrogen to emulate cryogenic fuel. The pipe continued to provide
solid data throughout all of the extreme conditions. The next phase of the
project will include the Additive Manufacturing of a larger pipe section for
use at NASA Stennis Space Center.