Biofuels : A hope for greener aviation

In the 1930’s, the aviation industry was in the midst of the major transformation as aircraft manufacturing was getting modernized. Even though in the first sight at some of the present aircraft, we can say it’s pretty similar like as it looked in the era of 1960’s i.e. it was basically a long metallic tube with some wings on its sides, but as we get closer to have a clear view at these, planes of today are:

• made of much lighter materials including composites,
• engine is far more efficient now,
• Several interesting aerodynamic features like winglet has been introduced for the plane to fly more efficiently.
• Even when it comes to the fuel efficiency, we have seen an improvement of about 70% in last 40 years.

But the one thing, I wish to point out has not changed in last whole century is that the enormous amount of fuel is being used, which is even adding up to increase the pollution level with reducing amount of fuels in the nature at a great rate. The world is turning to governments and business to reduce the human impact on climate change. But in the recent past we have just got a clue about a new change that can be seen in upcoming future with the responsibility to revolutionize the aviation industry yet once again embark on a new journey.

Bio-fuels : A hope for greener aviation

Sustainable bio-fuels can be crucial to providing a cleaner source of fuel to power the world’s fleet of aircraft and help the billions of people who travel by air each year to lower the impact of their journey on our planet. Over the last couple of years, we have seen a major move forward towards the industries interest in the potential and sustainable bio-fuels for aviation. We have now even seen a whole series of successful test flights. Infect it has been so successful that we can now expect at least a small quantity of sustainable bio-fuel to start being used commercially in the next 3 to 5 years. Hence bio-fuel can be yet another milestone to be added in the history of aviation industry. Its use has been gaining popularity over the past few years because of their ability to reduce the dependence on fossil fuels. As a renewable energy source, bio-fuels is seen as a viable option for sustaining long-term energy needs if they are managed efficiently.

But after all, it is yet to be seen that how successful it can be in ever grooming Aviation Industry and how well it can compete with the era of fossils in the future.

The Reddy Tube: Converting a Destructive Wave into the MAGICAL WAVE

There, I was attending a talk on the topic of “GREEN ENERGY” at an event organized by IMechE, when I first came across this extraordinary person “Dr. K. P. J. Reddy” who was there to talk about his research on the shock waves. Being, an aerospace graduate I was quite excited about the topic of “Shock Waves” as the only reason we had to study about it is because of its nature to retard the airplane or any capsule.
Prof. KPJ Reddy can be, without any doubt can be credited with the title of “Father of Shock Waves Technology”, in reference to his works in the field of Shock Waves and Shock Tube. Thanks to his research, soon we can find a Hypersonic Tunnel in the laboratories of every aerospace institutions with an Indian brand name “THE REDDY TUBE”.

Prof. KPJ Reddy and Prof G Jagadeesh, the scientist duo behind Reddy Tube research 

Some of the key points regarding Reddy tube and its possible availability in Aerospace institutions are below:

• Prof K P J Reddy from the Department of Aerospace Engineering, IISc claims to have developed a miniature version of the hypersonic shock tunnel that will make it feasible for any institute to have such a facility. 

Modified Reddy tube with 4 mm diameter shock tube

• The size of regular shock tunnels varies from 10 meters in length to more than a hundred meters.
• It consists of two sections: a 400-mm-long driver tube with a manually operated piston and a 600-mm-long driven tube. The two parts are small enough to be put on a tabletop and allow students a hands-on experience with hypersonic.

• The shock tunnel was named after Prof K P J Reddy, who is the godfather of Hypersonic and Shockwave Research in India.
• He had achieved a breakthrough by producing a shock waves even in syringe-sized tubes, which was later  fabricated to give the name of “the Reddy Shock Tunnel”

A medical syringe converted into piston-driven mini shock tube

Schematic diagram of the Reddy Tube

• It’s compact and allows basic hypersonic research to be conducted in an educational institutions.
• This Shock tube can create shock waves in the laboratory environment and allow researchers and students to study the shock waves deeply. 
• Prof K P J Reddy also claims it to be very useful in:
• transferring genes to a cell
• drying tea leaves quickly
• artificially inseminating farm animals
• delivering drugs without using needles and various other applications.
• By Latest, Prof. Reddy and his team are investigating the possibilities of shock wave technology for extracting gas, through an agreement signed with the state-run explorer Oil and Natural Gas Commission (ONGC). 

Dr. KPJ Reddy : A man Who Played with most dangerous natural wave

Wishing a great success ahead to the team of Dr. KPJ Reddy and his team. Wish your team many more successful research to give us more reason to be proud of your research works

NOTE:

 What is Shock Wave?

• A shock wave is a small area of high pressure and temperature in a gas or liquid that travels at supersonic speeds. The thickness of the area of high pressure and temperature is small, as small as one-millionth of a meter, but it is enough to cause many physical effects when it hits something. Shock waves are produced whenever energy is released in sudden bursts. In nature, they are produced during lightning, earthquakes and explosion or in some cases by supersonic aircraft. Crackers produce weak shock waves.

                                                          Or in physical observance,

• At speeds below that of sound, the air in front of the object moves away, allowing the object to move forward smoothly. As you keep increasing the speed — when it surpasses the speed of sound — a ‘disturbance’ is formed in the area around the object. The air in front of the object begins to change, increasing in pressure, density and temperature, sharply and abruptly. Such a disturbance is called a ‘shock wave’.”

A tiny engine which works on changes in bacterial activity

Researchers from Indian Institute of Science (IISc) and the Jawaharlal Nehru Centre for Advanced Scientific Research have designed a microscopic heat engine that relies on changes in bacterial activity.

BREAKTHROUGH ACHIEVED: Scientist Ajay K. Sood (seated) with scholars Subho Ghosh (left) and Sudeesh Krishnamurthy in Bengaluru

some of the key points of the research are:-

• It relies on changes in bacterial activity.
• It operates at 50-60 per cent efficiency, which is quite high as compared to the engines we use at present

Working :

• It relies on very small changes in temperature input to impact bacterial activity to achieve large work done by the engine against the other existing engines which require a very high amount of temperature difference. 
• This engine uses a colloidal particle of 5 micro-metre size, optically trapped using a laser beam
• The extent to which the particle can move is controlled by varying the intensity of the laser beam — the more the intensity the less the particle can move and vice versa.
• At high temperature the intensity of the laser beam is reduced and the particle can get displaced more; leading to increased intensity at lower temperature.

Process: 

The change in temperature, which is carried out every four seconds, leads to changes in bacterial activity and hence the work done by the engine.

Key Factor : Efficiency

• “The temperature difference is too small to get work done. The efficiency of the engine will be around three per cent at this temperature difference. But due to bacterial activity the efficiency is over 50 per cent,” says Prof. Ajay K. Sood, the corresponding author of the paper from the Department of Physics, IISc.
• He further adds "When the bacterial activity is high at 40 degree C the effective temperature is around 2000 degree C; at 17 degree C the bacterial activity is significantly diminished leading to low effective temperature"
• But still challenges are there :While the tiny heat engine outperformed a conventional engine in efficiency, it is still far less efficient compared with biological motors that operate in our bodies at 100 per cent efficiency even when the temperature remains constant.

"The next step is to connect the heat engine to some nano device or electromechanical device,” Prof. Sood says.