Inspired by Emperor Penguins, CSSC Shanghai Shipyard launches second-generation smart BLS to the world

China News Service, Shanghai, October 17 (Li Qiuying, He Baoxin) On October 17, CSSC Shanghai Ship Research and Design Institute officially released its independently developed second-generation intelligent ship bubble lubrication and drag reduction system (BLS) to the world in Shanghai. This system has been applied to a newly built 50,000-ton product oil/chemical tanker for the first time. Maritime verification has shown that it can achieve a net energy saving of about 5% and the energy efficiency index has also been significantly improved.

BLS technology is inspired by the survival skills of emperor penguins. An emperor penguin feeds on krill underwater in the Weddell Sea at the northern tip of the Antarctic Peninsula. Suddenly, it spotted a harbor seal swimming toward it menacingly from a distance. The penguin immediately turned around and fled to the nearest ice floe, using all its strength to accelerate to a speed of nearly 20 kilometers per hour. The harbor seal also used its explosive power and quickly caught the penguin at a top speed of 40 kilometers per hour. At the critical moment, the penguin shakes its body and releases a large amount of air originally stored in the dense scaly feathers into the water, creating millions of micro-bubbles. An "air lubricating film" is immediately formed between the body and the water, greatly reducing the resistance of the water. The bubbles also interfere with the seal's sight. With this coat of microbubbles, the emperor penguin greatly increased its sprinting speed, and finally jumped up onto the ice, successfully "leopard" out of danger.

Schematic diagram. Photo courtesy of CSSC Shipyard

This survival trick evolved by emperor penguins is now being used in ship energy-saving and drag-reduction technology.

The principle of BLS is to continuously release compressed air to the bottom of the ship to form a stable layer of microbubbles between the hull surface and seawater, thereby converting the seawater boundary layer around the hull into a gas-liquid mixed flow. Taking advantage of the different physical properties of air and water, it can effectively reduce the frictional resistance of the ship during navigation, thereby reducing the main engine load and fuel consumption. BLS can not only save energy and reduce drag, but also inhibit the adhesion of marine organisms on the bottom of the ship and reduce the impact of ship bottom fouling. As a green ship technology recognized by the International Maritime Organization (IMO), BLS has the characteristics of flexible installation, strong adaptability, and short investment return period. It can be widely used in various types of merchant ships such as container ships, oil tankers, gas carriers, ro-ro ships, and cruise ships. It is one of the important means for the shipping industry to cope with environmental protection regulations and achieve carbon emission reduction goals.

Picture of the operation after installing BLS on the bottom of the ship. Photo courtesy of CSSC Shipyard

In May 2022, after completing the first generation of BLS, experts from the Innovation Center started research on the second generation of intelligent BLS. Different from past sea trial verifications, this operational verification conducted on a 50,000-ton product oil/chemical ship covered multiple voyage segments, multiple drafts, and multiple sea conditions, and was a completely real operating scenario. During the five-month actual ship operation test, the BLS air supply module and intelligent control module operated stably. Through the periodic automatic starting and stopping of the system, the ship's navigation status data is recorded in real time, and the energy efficiency comparison data of the same ship under different drafts, speeds, etc. can be obtained to directly and accurately reflect the energy-saving contribution of the system in actual operations. It is reported that the 3,300TEU feeder container ship equipped with the second-generation intelligent BLS will be completed and delivered in the near future.