The European carrier rocket Vega has already been launched to
space twice to carry satellites to their destinations. At DLR, it has
completed such a flight over 50 times – albeit as a miniature version
in a wind tunnel. Seventy-five centimetres long and made of steel
and titanium, the model is used by the DLR engineers to simulate
the separation of the lower and upper stages in the hypersonic wind
tunnel in Cologne. This is one of the most critical moments in such
a flight, and staff in the Supersonic and Hypersonic Technology
Department at the Institute of Aerodynamics and Flow Technology
are aware of this.
Under contract to the European Space Agency, ESA, the engi-
neers have been using the wind tunnel to investigate how the flow
around the rocket varies during the stage separation. They have used
a highly accurate set of instruments to measure the forces and
momentum that affect the rocket during the stage separation. To
make the change in flow along the rocket visible – it had previously
only been calculated in computer models – they also put oils with dif-
ferent viscosities on the model throughout the measurement
sequence, and recorded the changes in this film of oil. The most
important finding was that the flow field around the rocket is dis-
turbed enormously during the stage separations. Asymmetrical vorti-
ces are generated that separate the flow. The measurement data can
now be used to better define the optimum time for stage separation.
Vega rocket model in the wind tunnel in Cologne
Determining the right proportion of air and fuel is one of the big
challenges facing engine manufacturers. The ratio of the two
components is critical to the stability and efficiency of the com-
bustion as well as the amount of pollution produced. Fuel and
air are mixed in the burner. Conventional burners are built in
such a way that they ensure stable combustion under any oper-
ating conditions. This is because an aircraft engine is expected
to function reliably under any circumstances. However, the func-
tional range of an aircraft engine has to be very large. It includes
rolling out onto the runway with low engine output; the take-
off process requires maximum engine output. This involves a
compromise in the burner design that has previously meant that
better use of exhaust gases occasionally had to be sacrificed.
This is the issue now being addressed by JAXA and the
DLR Institute of Propulsion Technology. The scientists are
attempting to influence the distribution of air in such a way that
the stabilisation limits for the combustion are extended. The sci-
entists want to achieve this by discharging the air through small
channels at specific points in the burner in a targeted manner.
This process is known as fluid control and has the potential to
make future generations of engine more effective and less pol-
lutant.
In brief
DLR and the Japanese Aerospace Exploration Agency JAXA have been collaborating in the area of aircraft engines since
2010. This collaboration has recently been extended for another three years.
German-Japanese collaboration for improved engine burner
:envihab opens its doors
DLR engineer Denis Schneider and his Japanese colleague Seiji
Yoshida have a common goal: that the burners of the engine will
produce less exhaust fumes.
To record the variations in the air flow,
engineers placed a film of oil on the model
of the Vega rocket. The images show how
the oil particles are distributed when
subjected to various experimental conditions.
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This summer, :envihab was inaugurated at the DLR site in Co-
logne. Now, DLR scientists can offer international space agencies
and universities a globally unique research facility. Human health
is studied in its eight modules, which are spread over 3500 square
metres, and include a centrifuge, a hypobaric chamber and a pos-
itron emission and magnetic resonance tomography unit. Another
unique feature is the capacity to perform an ultrasound screening
on a test subject during a session at the short-arm human centri-
fuge using a robotic arm. A one-of-a-kind combination of re-
sources.
Here, the scientists will not only focus on the effects of liv-
ing in space, but on life on Earth as well. For instance, the mea-
sures the scientists have developed to counteract the effects of
weightlessness in space will also help with bone and muscle dete-
rioration following a lengthy confinement to bed or in old age. To
better understand these effects, a two-month bedrest study will
soon be carried out in the Sleep and Physiology Laboratory at :en-
vihab.
:envihab will be open to visitors on 22 September 2013. The research
facility serves as a communications centre as well.
The crew of the Falcon flight campaign
confirmed: the solar wind does not
contribute to the radiation field at cruising
altitudes.
The twelfth DLR School_Lab in Germany will be open to students at
RWTH Aachen University as of the coming school year. The subjects
range from the areas of aerospace, energy and transport research,
with a special focus on robotics and artificial intelligence. An ‘ener-
gy-intelligent’ town will be controlled, a quadrocopter will be flown
using bodily gestures, driver assistance systems will be tested, and
industrial and humanoid robots programmed. One unique experi-
ment is ‘A Walk on Mars’. In the Holodeck in the laboratory, stu-
dents can go on a virtual treasure hunt through Gale Crater on
Mars.
New DLR_School_Lab in Aachen
Learning while playing: the ‘energy-smart’
city.
When the surface of the Sun is covered in sunspots, the eruptions
of material and solar wind blowing towards Earth are stronger. This
has caused many people to wonder about the effect of radiation at
aircraft cruising altitudes. Surprisingly, radiation exposure levels
decrease. DLR scientists confirmed this in a measurement campaign
in early summer 2013. Using the DLR Falcon research aircraft, they
flew over Bavaria and southern Norway. The measurements showed
that the exposure to radiation at cruising altitudes, when compared
to similar measurements taken in late 2007 – close to solar mini-
mum – was actually around 10 percent lower as a result of
increased solar activity.
The Radiation Protection in Aviation working group at the DLR
Institute of Aerospace Medicine in Cologne has been investigating
this problem since 2004. The solar wind clearly does not contribute
to the radiation field at cruising altitudes, as the radiation of parti-
cles from the Sun generally lacks the energy necessary to penetrate
deep enough into the atmosphere. High-energy cosmic radiation,
on the other hand, encounters various air molecules in the upper
layers of the atmosphere, at an altitude of around 10 kilometres –
high above normal flight corridors. This gives rise to secondary parti-
cles. The DLR scientists used detectors to study the interaction with
matter.
Solar activity reduces radiation exposure in the air
