http://www.wimp.com/prototypeengine/
Thought I'd share. Pretty interesting, never heard of any ideal like this before.
Mach 5 engines
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Re: Mach 5 engines
I've heard of the company and read about the engine concept before.
The "big idea" is that the vehicle carries an amount of cryogenic material with it which it uses as the heat sink for the heat exchanger the video discussed. The latent heat of the change of state of the cryogen from liquid to gas "powers" the heat absorption of the heat exchanger. The expansion of the cryogen as it undergoes its change of state can then be used to drive the turbopumps that operate the engine.
At supersonic speeds in the atmosphere, the intake air for the engine is heated by compression as the aircraft pushes through the air. This phenomenon in what limits conventional ramjets to mach 5, as the drag created by the convergent inlet nozzle as it slows down and compresses the inlet air to subsonic speeds exceeds the thrust the engine can produce.
Conventional turbines have similar limits in that they can only ingest subsonic air. Current supersonic aircraft have inlet ducting that slows supersonic intake air to subsonic speeds. The most advanced example of this are the variable "shock cones" at the front ends of the SR-71 engines. The video shows their proposed vehicle as having similar shock cones.
By cooling the intake air, the heat exchanger reduces the drag involved in slowing down the inlet air and dramatically improves the efficiency of the engine. The more cryogenic material the vehicle carries, the more effective the heat exchanger will be. This pushes the design toward both fuel and oxidizer as cryogens. The fuel would be liquid methane or liquid hydrogen and the oxidizer would be liquid oxygen.
If fuel is used in the heat exchanger, the fuel goes straight into the engine to combust with the air it just cooled. As the vehicle "subtly transitions" from aircraft to rocket, more oxidizer is added to the mix. The oxidizer can flow through the heat exchanger and go into the engine alongside the intake air like nitrous injection into a piston engine, OR...
As the vehicle leaves the atmosphere, airflow through the atmospheric engine will drop and the engine will "transition" somehow to operating purely as a rocket. It appears, based on the multiple exhaust nozzles pictured in the cutaway in the video that the rocket chambers and nozzles are completely separate from the atmospheric engine. The cooling of the incoming air provides heat that can be used to drive the turbopump operating the engine. As the vehicle leaves the atmosphere, that heat source goes away and something else has to do that job. That could be a conventional pre-burner easily enough.
There's more but I have to crack on with things...
I wouldn't mind a go at that rocket scientist chick in the video, though.
The "big idea" is that the vehicle carries an amount of cryogenic material with it which it uses as the heat sink for the heat exchanger the video discussed. The latent heat of the change of state of the cryogen from liquid to gas "powers" the heat absorption of the heat exchanger. The expansion of the cryogen as it undergoes its change of state can then be used to drive the turbopumps that operate the engine.
At supersonic speeds in the atmosphere, the intake air for the engine is heated by compression as the aircraft pushes through the air. This phenomenon in what limits conventional ramjets to mach 5, as the drag created by the convergent inlet nozzle as it slows down and compresses the inlet air to subsonic speeds exceeds the thrust the engine can produce.
Conventional turbines have similar limits in that they can only ingest subsonic air. Current supersonic aircraft have inlet ducting that slows supersonic intake air to subsonic speeds. The most advanced example of this are the variable "shock cones" at the front ends of the SR-71 engines. The video shows their proposed vehicle as having similar shock cones.
By cooling the intake air, the heat exchanger reduces the drag involved in slowing down the inlet air and dramatically improves the efficiency of the engine. The more cryogenic material the vehicle carries, the more effective the heat exchanger will be. This pushes the design toward both fuel and oxidizer as cryogens. The fuel would be liquid methane or liquid hydrogen and the oxidizer would be liquid oxygen.
If fuel is used in the heat exchanger, the fuel goes straight into the engine to combust with the air it just cooled. As the vehicle "subtly transitions" from aircraft to rocket, more oxidizer is added to the mix. The oxidizer can flow through the heat exchanger and go into the engine alongside the intake air like nitrous injection into a piston engine, OR...
As the vehicle leaves the atmosphere, airflow through the atmospheric engine will drop and the engine will "transition" somehow to operating purely as a rocket. It appears, based on the multiple exhaust nozzles pictured in the cutaway in the video that the rocket chambers and nozzles are completely separate from the atmospheric engine. The cooling of the incoming air provides heat that can be used to drive the turbopump operating the engine. As the vehicle leaves the atmosphere, that heat source goes away and something else has to do that job. That could be a conventional pre-burner easily enough.
There's more but I have to crack on with things...
I wouldn't mind a go at that rocket scientist chick in the video, though.