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Original or modified images and movies are not allowed to use without permission.

Real-time imaging of carbon dioxide emissions form aircraft


Environmental Advances, "On-Site Direct Imaging of Carbon Dioxide Emissions from Aircraft during Landing and Take-Off Cycle"

On-site direct and selective imaging of CO2 emissions from aircraft was successfully performed at Fukuoka International Airport in Japan. We employed the latest infrared camera with a remarkably narrow bandpass filter ranging from 4.2 to 4.4 micro-meter, corresponding to the low-transmittance wavelength of CO2. 


High-speed visualization of rocket engine internal dynamics


AIAA Journal of Propulsion and Power, "Visualization of Pulse Firing Mode in Hypergolic Bipropellant Thruster", G.Fujii(D1)AIAA Journal of Propulsion and Power, "Visualization of coolant liquid film dynamics in hypergolic bipropellant thruster", G.Fujii(D2)

A quartz class chamber is used to visualize the mutiphase combustion dynamics in a rocket engine operating under subcritical pressure. 

Film cooling fuel spreading on the internal wall is clearly visible.

Rocket engine performance prediction


We successfully predict the performance of chemical propulsion systems, e.g. characteristic velocity. specific impulse and thrust by the newly developed theoretical model.  The figure shows unlike impinging atomization. 

Liquid sheet dynamics and phase change on a wall driven by fast gas stream


Liquid sheet sheared by an ambient gas flow is useful for cooling a combustion chamber wall. On the other hand, the film may cause icing or eroding machine parts. For utilizing properly liquid films, it is greatly desired to predict its flow characteristics including the wavy structure and the entrainment.

The movie shows dynamics of the liquid sheet with thickness of 1mm subjected to the air stream of 30 m/s.

Optimum design of liquid rocket engine to realize the maximum Isp and the best film cooling


AIAA Journal of Propulsion and Power, "Optimal Liquid Engine Architecture by Performance-Cooling Tradeoff Analysis", S.Tauchi(M2)

Successive fragmentation cascade-Physics of beauty-


A single droplet breaks up just once in general, at high-pressure diesel spray and by subjected to super-sonic flow. Contrary, we have discovered that an isolated droplet can successively fragment approximately 10 times through the self-similar cascade in the spark ramification process observed at Senko-hanabi (線香花火), which originated in Edo-period, 4 centuries ago. The continuous internal gas production drives the bursting events of the droplets.

Successive branching of metal sparks


A single metal droplet of carbon steel branches multiple times, whose mechanism has not been known for more than 200 years. We are trying to elucidate it by high-speed measurement.

The figure is a carbon steel spark with a radius of 10 micrometers flying at 30 m/s.

Liquid metal fragmentation


Powder metallurgy and metal AM technology, utilizing for making aircraft parts such as fuel injection nozzle, need fine and spherical metal powders.

Water atomization is one of the most general methods to produce metal powders. 

We succeeded in the detailed high-speed observation and modeling of liquid metal fragmentation process.

Real-time bubble/droplet tracking above 1kHz


We have firstly succeeded in real-time (in-situ) detection and tracking of bubbles and droplets at exceeding 1,000Hz for measuring the number, size, and velocity by using the latest high-speed streaming camera.

Fragmentation and solidification process of a single ligament


The water ligament (left) without solidification breaks into several spherical drops by surface tension. Contrary, the fusible alloy (right) fragments affected by solidification, leading to the irregular topologies of daughter particles.

Viscous sheet instability and breakup


Viscous  liquid sheet on the inner wall of the pipe suffers a shearing high-speed air flow. Instabilities drive the sheet into the wavy pattern with droplet entrainment from the surface, eventually disintegrating into droplets at the bottom end.

Airblast sheet fragmentation in jet engines


Air-blast atomizer for jet engines, in which liquid sheet breaks up due to high-speed air streams, is a crucial component both for performance and environment. The spray characteristics are clarified by high-speed visualization, newly developed mechanical patternator measurement, laser diagnostics, and multiphase CFD. The picture shows a high-speed visualization of 2D liquid sheet. 

Bouncing droplet on liquid film


When a droplet is photographed with a high-speed camera, an interesting phenomenon occurs where the droplet rides nicely on the liquid film and bounces around. 

The movie on the left is shot with a thin droplet thickness, and the movie on the right is shot with a thick droplet thickness, using water as the liquid. The difference between the thin and thick cases is the number of steps it takes for a droplet to be absorbed by the film, and the size of the second droplet that is formed once it is absorbed.