American scientists use light technology to control hypersonic jet engines

According to the website "interesting engineering" on July 29th, a new study funded by the National Aeronautics and Space Administration (NASA) has revealed for the first time that the airflow in supersonic combustion jet engines can be controlled through optical sensors. This study was conducted by researchers from the School of Engineering and Applied Sciences at the University of Virginia.

When the 'shock wave train' appears, this study allows operators to control the airflow at the speed of light. The 'shock train' is a condition that occurs before the failure of a scramjet engine.

The previous method relied on pressure sensors to monitor the airflow through supersonic combustion jet engines, but this new breakthrough enables the same operation to be achieved using optical sensors.

NASA funded research
In 2004, NASA's hypersonic jet aircraft "Hyper-X" set a record for flying faster than any other aircraft.
In the final test held in November 2004, the X-43A unmanned prototype set a world record with a speed of 10 Mach, which is 10 times the speed of sound. Prior to this, this speed could only be achieved by rockets.

This breakthrough has led to a significant shift in the development of jet aircraft, from ramjet engines to more efficient scramjet engines. Although the hypersonic concept validation has been successful, the main challenge lies in implementing engine control, as the technology relies on old sensor methods.

However, this new breakthrough at the University of Virginia brings some hope for future X-series aircraft that can fly at hypersonic speeds.
In addition to demonstrating that the airflow in supersonic combustion jet engines can be controlled through optical sensors, this NASA funded study also achieved adaptive control of scramjet engines.

Researchers say that adaptive engine control systems can respond to dynamic changes to maintain optimal overall system performance.
Professor Christopher Goen, Director of the Aerospace Research Laboratory at the University of Virginia, stated that since the 1960s, the focus of American aerospace has been on building single-stage to orbit aircraft that can take off horizontally into space like traditional planes and land on the ground like traditional planes.

Goen said, "Currently, the most advanced spacecraft is SpaceX's Starship. It has two stages, vertical launch and landing. However, in order to optimize safety, convenience, and reusability, the aerospace industry hopes to build spacecraft more like the 737.

Optical sensors are crucial for hypersonic aircraft
Goen said, "For us, it seems logical to embed sensors that work at speeds closer to the speed of light than sound if the aircraft is operating at hypersonic speeds of 5 Mach and higher.
The University of Virginia has multiple supersonic wind tunnels that can simulate the engine conditions of hypersonic aircraft flying at 5 times the speed of sound.

Goen explained that the "supersonic combustion ramjet engine" is an abbreviation for the "supersonic combustion ramjet engine", which was developed based on the commonly used ramjet engine technology over the years.

Currently, like ramjet engines, supersonic ramjet engines require an increase in speed to intake enough oxygen to operate.
The latest innovation is the dual-mode scramjet combustion chamber, which is also the type of engine tested by the project led by the University of Virginia. This dual-mode engine starts in scramjet mode at lower Mach numbers and then transitions to receive fully supersonic airflow in the combustion chamber at speeds exceeding 5 Mach.

Unlike pressure sensors that can only obtain information on the engine wall, optical sensors can identify subtle changes inside the engine and flow channels.

This tool analyzes the amount of light emitted by the light source (in this case, the reactive gas inside the combustion chamber of a scramjet engine) as well as other factors such as flame position and spectral content.

The first proof of implementing adaptive control
According to a press release from the University of Virginia, wind tunnel demonstrations demonstrate that engine control can be predictive and adaptive, enabling a smooth transition between scramjet and scramjet functions.

The press release points out that in fact, this wind tunnel test is the world's first proof that adaptive control can be achieved through optical sensors in this type of dual function engine.

The team believes that optical sensors may be a component of future space travel similar to airplane travel.

This may help create an integrated aircraft that can glide back to Earth like the space shuttle used to.

Goen said, "I think it's possible. Although the commercial aerospace industry has reduced costs through some reusability, they haven't yet achieved aircraft like operations. Our findings have the potential to make space access safer than current rocket based technologies, building on the glorious history of Hyper-X.

Source: Yangtze River Delta Laser Alliance