Designing and Aerodynamic Performance of the Combined-Cycle Engine Inlet in a Hypersonic Flow

Paper number

IAC-05-C4.5.06

Author

Mr. Kouichiro Tani, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan

Coauthor

Mr. Takeshi Kanda, Japan Aerospace Exploration Agency (JAXA/Kakuda Research Center), Japan

Coauthor

Mr. Kanenori Kato, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan

Coauthor

Mr. Noboru Sakuranaka, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan

Coauthor

Mr. Shuuichi Watanabe, Japan Aerospace Exploration Agency (ISTA/JAXA), Japan

Year

2005

Abstract

In the future, where the space environments and resources will be
essential to sustain ever-growing human activities, the reusable launch
vehicles (RLV) will take a pivotal role for the space developments.  One
of the key technologies to realize RLV is its propulsion system. In
JAXA Kakuda, a combined cycle engine (CC-engine) which can produce
sufficient thrust over entire flight range of RLV, is now intensively
investigated aiming to use it as a propulsion device for the
single-stage-to-orbit RLV. For the sub-scale engine test being due start
in couple of years, the finalization of the engine configuration is now
at the primary concerns of JAXA Kakuda.\\

CC-engine employs semi-constrained single flow passage and changes
combustion cycles in accordance with its operation speed. Thus, it can
reduce the bulk space and weight. On the other hand, it is rather
difficult to keep high aerodynamic performance without suitable
geometrical compensation for flow control.  In practical meaning,
though, due to the cooling system which is required to resist high heat
flux in the super/hyper sonic speed, variability of the engine
configuration must be compromised.\\

In the current study, a designing methodology for the CC-engine inlet
with fixed geometries was first explored. The CC-engine inlet is
expected to have high air capturing capability in a hypersonic speed,
while it also should posses the good starting performance in low Mach
range. In subsonic and transonic regime, it has to ensure the choking
flow condition in an ejector-jet mode.  In the current method, the basic
design point was chosen at an arbitrary hypersonic speed (Mach 10)
aiming ``full'' air capture capability at that speed. Three geometrical
variations were selected and compared in supersonic to hypersonic
region for their aerodynamic performances, such as the total pressure
loss, capture ratio and compression rate. The comparison was carried out
by a simple 1D/2D wave calculations and 2D inviscid CFD analysis
were also conducted to examine the complicated wave interactions
effects. The results indicated that ``two-stage'' ramp configuration had
a good potential in the aerodynamic characteristics.\\

The actual test in a wind tunnel which can produce Mach 6.7 and 5.4
flows were also carried out. The experimentally obtained aerodynamic
performances were compared with the analytical results, and the
discrepancies were discussed. Especially, in the experiments, the effect
of the incoming boundary layer thickness were examined by changing the
relative position of the model in the wind tunnel.  The experimental
results also supported the superiority of the two-stage model.

Abstract document

IAC-05-C4.5.06.pdf

Manuscript document

IAC-05-C4.5.06.pdf (🔒 authorized access only).

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