At a time when countries are racing to find ways to improve the speed and stealth of their submarines, a team of researchers at Shanghai Jiao Tong University’s State Key Laboratory of Mechanical System and Vibration has reportedly claimed that its a newly developed pump-jet propulsion system can give Chinese submarines a higher thrust while reducing noisy vibrations by more than 90%.
Over a decade ago, Chinese submarines were notoriously loud, which made them easier to track. Now, China has made rapid strides in the redesigning and reconfiguration of submarines, making them stealthier and quieter.
The shrouded propeller used in some modern submarines puts the rotor in a duct to generate a jet of water for propulsion, according to a South China Morning Post (SCMP) report. However, there is a gap between the rotor blades and the duct’s inner wall that, although small, produces turbulence or bubbles when the blades spin rapidly, slowing the submarine and giving away its location.
A team of researchers led by Professor Hua Hongxing claimed in a research paper, published in the Chinese journal Ship Research on Oct. 10, that it has been able to eliminate this gap between the rotor blades and the duct’s inner wall, according to the SCMP report. To do this, the researchers have reportedly dug a trench in the duct wall, allowing the rotor tips to move freely inside.
For the new design to work properly, the new pump jet requires a sealing material that can keep water out of the trench without impeding the rotor’s movement.
The Chinese researchers have found the right material and built a soft sealing structure made of fine fibers that could meet these requirements, but the exact nature of the material remains classified, the report added.
Simulation experiments undertaken by the team at a ground testing facility have indicated that the new design could increase the thrust of a pump jet at slower speeds, at the same time reducing the noisy vibration significantly “at most characteristic frequencies,” the report quoted the research paper as saying.
To increase the power and stealth of its submarines, China has been carrying out a massive program for upgrading and developing its strategic nuclear-powered ballistic missile submarines while also using deceptive tactics to hide their identification numbers.
The Chinese team’s design innovation comes at a time when researchers around the world are struggling to find ways to meet the demand for newer technologies to improve submarines’ performance, stealth and strike capability amid cuts in defense funding.
Beijing, on the other hand, has invested heavily in its military modernization program with an aim to become the dominant force in the Asia-Pacific and strategic world power.
An earlier report highlighted how Chinese scientists who worked in the U.S. Los Alamos National Laboratory went back to China to advance the country’s developments in hypersonic missile, drone technology and submarine programs, all of which present an array of global security risks today.