Hypersonic vehicles travel at least four times faster than the speed of sound or greater then Mach 4. An airplane, missile or spacecraft can be a hypersonic vehicle. Hypersonic air breathing systems offer unprecedented class of flight vehicle encompass anthropometric and space access vehicles which allow rapid response at long range, great invulnerability and better survivability. Rocket boosters were used In the past to propel hypersonic vehicles. Rockets carry fuel that Is heavy making it pragmatic only for short and vertical flight.
Therefore the development of eightieth alarm breathing hypersonic vehicle has become the need. The temperature of the air rises when a fast moving vehicle travels through it as it compresses the air In front of it. This rise in temperature together with the heat of friction becomes terrific at very high speeds. Due to this extreme heat the air leading the fast moving vehicles makes a flare ball hotter than the surface of sun. To fly at the hypersonic speed and to reenter the atmosphere a vehicle must be designed to endure the shock waves and the searing heat due to friction.
Metals and gases behave In a efferent way at hypersonic speeds so special precautions must be taken to protect it and insulate the instruments and people on board from the heat. At higher speed a jet engine’s assemblies can no longer maintain the subsonic velocities needed for combustion. Thus a totally different design from a turbo fan or turbojet engine is required. Screamer – a special type of engine, supersonic combustion ramjet Is being deployed in hypersonic vehicles. We must take a look on the physics involved to understand how a Screamer engine works.
Jet engines and the rocket engines all work n the same principle as the balloon drawing at right. If the neck of the balloon is tied often forces due to pressurized gases in all directions cancel the effect of each other causes the balloon not to move. But If the neck of the balloon is open the unpunished forces causes it to fly like a rocket. Rockets and Jets work on the same principle. Unlike Jets, a ramjet does not have a compressor fan. They have tubes at both of the end with few internal parts. Ramjets vigorously compress and decelerate the arriving alarm prior to combustion.
The variant of the ramjet is Screamer so what’s the extraordinary thing about Screamer? Amazingly, the speed of the air through a Screamer engine never goes down the speed of sound. The combustion takes place In Screamer at supersonic airflow. The alarm Is decelerated to subsonic velocities before combustion takes place in ramjet but the airflow is always supersonic In Screamer. This makes the Screamer to function at exceptionally high speed. The three basic components a converging inlet, a combustion and a diverging nozzle completely formulate the sacrament’s body. Compression and deceleration of the incoming air is done in the converging inlet.
While this process is being carried UT atmospheric oxygen get mixed and burned In the combustion producing heat. 1 OFF nozzle. This will reduce the intricacy of compressor fan and numerous rotating turbine stages in Screamer. Hypersonic vehicle design restricts them to travel near hypersonic speed. As they short of mechanical compressor, the incoming air is compressed by the Screamer due to the kinetic energy. The kinetic energy of the hypersonic flow is incredibly high. A Screamer cannot turn out efficient thrust if not boosted to high speed around mach 5. Several means can be used to accelerate the Screamer to its required speed.
This can be incurred by turbo Jet, rail gun or rocket engine. Boeing X-AAA – a Screamer powered test craft was lifted by a Boeing 8-52 Stratospheres before it was released for flight height and accelerated by a separable rocket in the vicinity of Mach 4. 5. Screamer is a reimbursement of customary turbojet in many ways. It’s easier to manufacture because it has no rotating part. It does not have to take oxygen, has explicitly higher impulse than a traditional engine, will give cheaper access to space. The main incentive in pursuing hypersonic air breathing vehicles would be to diminish cost.
Although screamers are theoretically simple, practical implementation is facing technical challenges. A massive drag and immense rise in temperature of aircraft and that of engine is generated during a hypersonic flight. The fuel must be injected, mixed, ignited and burned within a millisecond. Also the plane that will fly at hypersonic velocity need to take off at subsonic, boost to supersonic and cruise at hypersonic speeds. This will add additional challenges to maintain combustion in supersonic flow. Despite the fact that Screamer technology has been underdeveloped since asses, currently screamers have fruitfully achieved ordered flight.
Hypersonic technology vehicle 1 (TV-I) and hypersonic technology vehicle 2 (TV-2) are crawlers, test rocket gliders developed and funded by DARPA falcon project (USA). These technologies are capable of striking any target in the world within one hour. In 2050, the aim of the hypersonic technology is to take off passengers. A hypersonic vehicle ‘Space Liner’ is being developed at the German Aerospace Center would whisk up to 50 passengers from Europe to Australia in one and a half hour. ‘Human beings must have action; and they will make it if they can’t find it. ‘ (Albert Einstein)