SCRAM JET

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TECHNICAL SEMINAR ON SCRAM JET ENGINE By A.LAKHAN 08951A2127

WHAT IS A SCRAM JET ENGINE?: 

WHAT IS A SCRAM JET ENGINE? A scramjet ( s upersonic c ombustion ramjet ) is a variant of a ramjet air breathing combustion jet engine in which the combustion process takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to forcefully compress and decelerate the incoming air before combustion (hence ram jet), but whereas a ramjet decelerates the air to subsonic velocities before combustion, airflow in a scramjet is supersonic throughout the entire engine. The fastest air-breathing plane is a SCRAM jet design, the NASA X- 43a which reached Mach 9.8.

PowerPoint Presentation: 

In scramjets, the engine inlet is designed so it doesn’t create as much compression as in a ramjet, allowing the air to zip through the engine at supersonic speeds. The simplest type of air breathing engine is the scramjet engine and simplified sketch of engine is given in figure.

COMPONENTS OF SCRAMJET ENGINE: 

COMPONENTS OF SCRAMJET ENGINE The scramjet is composed of three basic components: 1)A CONVERGING INLET, where incoming air is compressed and decelerated. 2) A COMBUSTOR, where gaseous fuel is burned with atmospheric oxygen to produce heat. 3) A DIVERGING NOZZLE, where the heated air is accelerated to produce thrust.

A SIMPLE DESIGN OF SCRAMJET: 

A SIMPLE DESIGN OF SCRAMJET

PRINCIPLE OF WOKRING : 

PRINCIPLE OF WOKRING Scramjet works on the same principle of Ramjet. All the operations are done by the varying cross section of passages. There are inlet passage, diffuser passage, combustion passage and exhaust passage. Basically in order to achieve the initial speed, a second engine is integrated in the Scramjet model, it may be rocket or turbojet engine.

PRINCIPLE OF WOKRING: 

PRINCIPLE OF WOKRING As these are air breathing engines, air from the atmosphere enters at very high speed in the inlet passage. In case of a scramjet the diffuser is merged with inlet. Hence the air from the atmosphere enters in the inlet section having very high velocity is reduced in diffuser section; thereby its static pressure increases. Temperature of air also increases when passing through the narrow cross section towards combustion chamber.

PRINCIPLE OF WOKRING: 

PRINCIPLE OF WOKRING Hot air flows in the combustion chamber and at this moment the propellant i.e. hydrogen (having a very low ignition temperature) are injected by the injector in the combustor. Where it gets self ignited within a millisecond and the combustion process is carried out at the supersonic speed. The fresh air supply to the diffuser builds up a pressure at the diffuser so that these burned gases cannot expand towards the diffuser. Instead, the gases are made expand in combustor towards tail engine hence providing the required thrust.

ADVANTAGES DISADVANTAGES: 

ADVANTAGES DISADVANTAGES Does not have to carry oxygen. No rotating parts makes it easier to manufacture. Less weight and simple design. As the hydrogen is used as a propellant and combustion is carried out at supersonic velocity with the help of oxygen from the atmosphere. As a result of that, steam (H2O) is being exhaust gas which is echo friendly in nature. A scramjet cannot produce efficient thrust unless boosted to high speed, around Mach 5. As a result an additional propulsion systems are required. Lack of stealth. Testing difficulties.

RECENT DEVELOPMENTS: 

RECENT DEVELOPMENTS Hyper-X “Scramjet” A new program, called Hyper-X, was launched by NASA in 1997. The goal is to build working jet airplanes that use a clever combination of ramjet, scramjet, and rocket engines to reach sufficient speeds to achieve orbit around the earth. These planes would use conventional rocket engines to get started and then switch over to ramjet power at Mach 2 or 3, and then scramjet power at about Mach 5.

RECENT DEVELOPMENTS: 

RECENT DEVELOPMENTS Hyshot “Scramjet” The University of Queensland in Australia launched a hypersonic “scramjet” on 30th July 2002, claiming a world’s first revolutionary engine that could one day propel airliner at 8000 km/hr or more.

RECENT DEVELOPMENTS: 

RECENT DEVELOPMENTS Avatar “Scramjet” AVTAR stands for “Aerobic Vehicle for Advanced Trans Atmospheric Research”. It is good news that Indian hose is also in court of race. Recently Air Commodore Raghavan Gopalaswami publicly announced in early July 2002 in the United States, AVTAR is the hyperplane concept that has been developed by India, through financial support from the DRDO (Defense Research and Developed Organization).

X-43: 

X-43

PowerPoint Presentation: 

ANY QUERIES? THANK YOU