Posted this on twitter and a lot of people started complaining that I have revealed some secret information. Just to be clear this is open source and was published openly in 2015. More than 5 years down the line an open source document is "secret" ? Come on, in all due probability this study was old news before it was officially published. Anyway here we go...........
DRDO conducted studies on scramjet combustor with alternating wedge shaped strut fuel injector. The tests were conducted at Mach 7, the recent HSTDV flight test was conducted at Mach 6. The tests were done at 3 angles of attack ( α = −3°, α = 0°, α = 3° ).
The results show that the geometry with negative angle of attack (α = −3°) have lowest ignition delay and it improves the performance of scramjet combustor as compared to geometry with α = 0°, α = 3°. The combustion phenomena and efficiency is also found to be stronger and highest in case of α = −3°.
The placement of the Combustor:
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Full view of the entire combustor/fuel injector arrangement :
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Test model used for the simulation study :
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The strut design. The holes are fuel injectors. The wedges are to create compression shock wave behind the strut. When the shock waves converge they will greatly increase the temperature and create conditions conducive for Ethylene ignition and combustion :
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From the simulations :
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The conclusions from the simulations are :
1. There is no impact of the wedge formed strut injector in upstream course towards the isolator when α = 0°. Meaning at α = 0°, the shockwaves created by the struts do not cause any backflow in the direction of the intake. All shockwaves are formed in the direction of the exhaust nozzle.
2. The flow properties, shock structure, mixing and combustion phenomena are exceptionally sensitive to the variation of the angle of attack. Here there is a displacement of the shock train in the upstream direction for a negative angle of attack was found. This shock displacement improved the combustion phenomena and decreased the ignition delay. This shock also helps in modifying the shock pattern in the combustor.
3. No thermal choking was found for this setup. The range increment in the different combustor is adequate to keep away from inlet instabilities.
4. The highest temperature found for a negative angle of attack α = −3° is approximately T = 2,980 K. The least ignition delay was enlisted for (α = −3°) more or less 95 mm downstream the fuel injection and longest ignition delay was found for positive angle of attack (α = 3°). The combustion efficiency is the best for α = −3°.
From the conclusions it is pretty clear that to create initial scramjet ignition just after separation of the first stage. The HSTDV is to be maneuvered to attain an angle of attack (α ) = −3°. That is the intake nose slightly pointing down. In this α we have the lowest ignition delay and the highest combustion efficiency. Once the ignition stabilizes we can go for α = 0°, as at the α we can get the maximum speed. Although speed will come at the cost of less than the optimum combustion efficiency.
Hard to say. The project is still an engine experiment similar to the LFRJ or the SFDR. Once the engine tech is mastered various weapons can come off of it. No official data is out on fuel tank capacity or payload size.What will be the Range and Payload of the Hypersonic Missile
According to your newly discovered favorite defense analyst - PKS, That is expected to be the Brahmos -2 aka the Zircon.India can have complete hypersonic cruise missile system in 4-5 years: DRDO
New Delhi [India], October 14 (ANI): In a major boost for India's missile strike capabilities, the Defence Research and Development Organisation (DRDO) has said that it can develop a complete hypersonic cruise missile system in the next four to five years which will have the capability to strike...www.aninews.in
PKS- your newly discovered favorite defense analyst has been saying this for years ( since 2015 to be precise) . I guess most click bait channels took it from there.Now, since you appreciate his sense of history more than his current analysis, it must be genuine in your book.Even your clickbait youtube channels can tell you zircon is brahmos 2, Amit.
IF DRDO is able to bring the technology for Hypersonic cruise missile, I don't think we will go for Brahmos Hypersonic cruise missile bcoz of cost.PKS- your newly discovered favorite defense analyst has been saying this for years ( since 2015 to be precise) . I guess most click bait channels took it from there.Now, since you appreciate his sense of history more than his current analysis, it must be genuine in your book.
I'm glad you are able to remember things that long considering you forget half the discussion here so often. Hope i won't be hearing from you about this same discovery anytime soon then.PKS- your newly discovered favorite defense analyst has been saying this for years ( since 2015 to be precise) . I guess most click bait channels took it from there.Now, since you appreciate his sense of history more than his current analysis, it must be genuine in your book.