Scramjet and ramjet engines
Q. Which of the following is/are true?
1) Ramjet accelerates the air to supersonic velocities before combustion.
2) Scramjet engines are faster and efficient than ramjets.- Published on 01 Sep 16a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2
ANSWER: Only 2
- A scramjet (supersonic combusting ramjet) is a variant of a ramjet air breathing jet engine in which combustion takes place in supersonic airflow.
- As in ramjets, a scramjet relies on high vehicle speed to forcefully compress the incoming air before combustion (hence ramjet), but a ramjet decelerates the air to subsonic velocities before combustion, while airflow in a scramjet is supersonic throughout the entire engine.
- This allows the scramjet to operate efficiently at extremely high speeds.
- In a ramjet, the combustion chamber - where the air is mixed with fuel and ignited - only works at subsonic speeds. So the intake slows the air down, releasing some of its energy as a shock wave, but this reduces fuel efficiency.
