Indian Hypersonic Propulsion Developments
- Thread starter Ashwin
- Start date
Inside #HSTDV from yesterday test. This is size of the vehicle. pic.twitter.com/qDy5AqXhI3
— Anup Sayare (@sayareakd) September 8, 2020
There are four main development milestones to a SCRAMjet powered hypersonic "vehicle".
1. Aerodynamics of vehicle.
2. SCRAMjet test on ground.
3. SCRAMjet test in flight without production of a net thrust.
4. SCRAMjet thurst producing tests in test flight.
India has completed Aerodynamics and initial SCRAMjet tests on ground and with today, at least one successful SCRAMjet test in flight. DRDO is not very open if it was a flight with SCRAMjet producing a net thrust or not. Soooo......
If it was a flight in which a net thrust was produced then we are at a stage equivalent to US (NASA) in 2004, parallel to their X-43A test.
If it was a flight in which a net thrust was NOT produced and this test was "merely" a captive test then this is equivalent to 1994-5 US-Russian-French JV SCRAMjet test (Kholod test).
The reason why the vehicle may not be producing a net thrust is because of drag. A fast moving hypersonic vehicle faces massive drag due to viscosity of air itself, which is proportional to square of relative velocity.
en.wikipedia.org
Hence it is possible for a vehicle to have a SCRAMjet engine without getting a net thurst to move it forward. Such a vehicle will loose velocity and hence the SCRAMjet will cease operation. One way around this, to only test the supersonic engine (rather combustion) by testing it in a falling object.
Australian HyShot and ISRO's SCRAMjet test were essentially testing using a sounding rocket and were such tests besides Kholod from Russia.
1. Aerodynamics of vehicle.
2. SCRAMjet test on ground.
3. SCRAMjet test in flight without production of a net thrust.
4. SCRAMjet thurst producing tests in test flight.
India has completed Aerodynamics and initial SCRAMjet tests on ground and with today, at least one successful SCRAMjet test in flight. DRDO is not very open if it was a flight with SCRAMjet producing a net thrust or not. Soooo......
If it was a flight in which a net thrust was produced then we are at a stage equivalent to US (NASA) in 2004, parallel to their X-43A test.
If it was a flight in which a net thrust was NOT produced and this test was "merely" a captive test then this is equivalent to 1994-5 US-Russian-French JV SCRAMjet test (Kholod test).
The reason why the vehicle may not be producing a net thrust is because of drag. A fast moving hypersonic vehicle faces massive drag due to viscosity of air itself, which is proportional to square of relative velocity.
Drag equation - Wikipedia
Hence it is possible for a vehicle to have a SCRAMjet engine without getting a net thurst to move it forward. Such a vehicle will loose velocity and hence the SCRAMjet will cease operation. One way around this, to only test the supersonic engine (rather combustion) by testing it in a falling object.
Australian HyShot and ISRO's SCRAMjet test were essentially testing using a sounding rocket and were such tests besides Kholod from Russia.
Last edited:
Difference between initial HSTDV launcher and the redesigned HSTDV launcher - caged interstage either replaced or covered up . Maybe it was the reason for the alleged first test failure of the launcher few months back due to possibly bad aerodynamic interaction.
A well-written article... kudos to the author, while reading you can feel like watching an Indian patriotic movie. I thought the vehicle was using kerosene but it is ethylene.
Some time later when the nozzle design attains maturity and the scramjet engine is able to ignite & combust for longer durations, we should start seeing wind tunnel models with control surfaces like wings, fins etc. That will allow proper aerodynamic drag measurements to be done.
— Strategic Frontier (@strategicfront) September 21, 2020
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:
Full view of the entire combustor/fuel injector arrangement :
Test model used for the simulation study :
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 :
From the simulations :
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.
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:
Full view of the entire combustor/fuel injector arrangement :
Test model used for the simulation study :
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 :
From the simulations :
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.
If I were to guess, I would say the range of HSTDV based cruise missile should be greater than the old 300km ranged Brahmos. I say that as the Brahmos also has a air-breathing engine and it flies at half the HSTDV's speed. The Brahmos can hit Mach 3 in 300 kms, the HSTDV should take longer than that to get to Mach 6. Therefore onboard fuel should present be in quantities that allow greater range.
As for payload, I am not sure it will carry any. If it does it will be very small warhead. The kinetic energy alone will do devastating damage, why is a warhead needed ? We are better off putting some good sensors in the internal payload space available. Also given the speed, the computing power of the guidance and navigation system has to be very high just to keep up.
An IISc prof writes on #HSTDV in layman terms. Good primer for those who have no engg background from Aerospace/Mechanical.https://t.co/ByfSWKsTdD
— वैमानिकी (@vaimaniki) September 23, 2020
#ShauryaMissile: #India successfully test-fires new version of nuclear-capable Shaurya Missile pic.twitter.com/kQDT59jY6e
— The Pioneer (@TheDailyPioneer) October 3, 2020
The first HSTDV test failed because of the booster's performance under high dynamic pressure. The booster issue was fixed for the second test which was by all accounts a major success.
— Saurav Jha (@SJha1618) October 5, 2020
Also, anybody saying that sustaining a scramjet for 22 seconds at Mach 6 is passe, clearly doesn't know what he/she is talking about.
— Saurav Jha (@SJha1618) October 5, 2020
India can have complete hypersonic cruise missile system in 4-5 years: DRDO
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
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
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.
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.
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.
