Hyperloop technology: It is aimed to travel at a top speed of 1100 km per hour.
In order to understand the working of Hyperloop,it is important to realize that Hyperloop is more an engineering innovation than a new physics phenomenon .That said,its a technological marvel only a mind like Elon Musk could come up with.
First how would you achieve supersonic speed?
1..One way would be to first decrease the density as drag depends propotionally on density of air sorrounding it.The heavier the air,the more work you have to do to move against it.
2 Another way to achieve this is to prevent "divergence drag."Before you worry that I have transcended into rocket science realm,note that there is something known as breaking the sound barrier.
After a particular speed,the hyperloop capsule cannot simply pass through air. It is moving so fast that it must push air along with it.
To understand this imagine a circular (Loop) tube filled with water with a piece of solid cork(capsule) inside it.Let us also say you have an imaginary lever to push this cork through this water filled circular tube.Humour me for a second by not thinking how this lever is not causing water to leak around the circumference.Now use the imaginary lever to try and drive the cork around the loop.You are essentially trying to push against the entire column of water.
Now make a hole through the centre of the cork from top to bottom face.
When you now push the cork through,water will basically go from the front of the cork through the hole and come up behind it.Naturally this means the resistance to move the cork is less.You are effectively transferring the pressure resissting the cork motion towards the back ,in effect using it to help you move forward.Making friends with an enemy,so to say.
The pushing of the entire weight of air in front of the capsule is described as "injection" effect by the technical paper on Hyperloop.If the Hyperloop had to push like an injection(the solid cork example) it would face a lot more drag.Then how can the capsule use the cork with a hole concept mentioned above to cause air in front to move to the back and push the capsule?
3 Hyperloop achieves this by having a giant inlet at its front that sucks in air and throws it out towards the back.
But before throwing it out,a set of two compressors compress the air even further to increase the back pressure meaning even more propulsion.
4 But what drives this compressor?
It is easy to realise that a compressor with such a formidable task at supersonic speeds needs immense power.But immense power means large amounts of fuel or energy.
If this was a fuel based system(like a jet engine),a large heavy tank of fuel would be carried by the capsule.(Also would you want a supersonic hurtling -through -air -fireball with a combustion chamber above your head- kinda transport?)
If this was electrical,the amount of battery needed on the capsule would be too large(another capsule in itself).
5 ...But what about the levitation of the capsule?It isint on any track is it?And levitating a heavy capsule containing people using air jets sounds expensive.
While the capsule is moving at high speeds,it is sorrounded by (slightly inclined) converging skis (think inclined flat plates) all around the capsule in a circle.
The air moving with the capsule is pushed against this wedge,stagnates and creates a pressure large enough to support the capsule.
Of course at low speeds this aerodynamic effect is not much and pressurised air jets from these skis keep the capsule floating.
Also to reach a decent movement speed,electromagnetic propulsion is used till the time the speed is enough for compressor to take over.
6 But hyperloop is not without its problems.Firstly creating a partial vaccum and maintaining it are expensive affairs.Even a small leak can be catastrophic.
Not only this,but compressors not only work to compress a gas,but gas being heated as a result of compression is a natural sideeffect.
This means one capsule is letting super hot gases at its exit and disposal of this heat is not yet clear in the technical paper yet.
However,an intercooler has been added between the compressors to cool the air.But additional measures must be adopted.
Most of the air is removed from inside a long tube and a levitated vehicle is accelerated through it using a linear electric motor and magnetic levitation. The vehicle can glide quietly at airline speeds for long distances due to the extremely low aerodynamic drag and non-contact suspension.
The system promises to be safe, quiet, weather-proof and energy efficient with no direct carbon emissions. Furthermore, it will be point-to-point, meaning for any user, the pod doors only open twice: once to let you in and once to let you out.
A growing global economy requires faster, cheaper, safer, greener and more efficient transportation modes. Roads, airports and ports are congested. The world hasn't had a mobility paradigm shift in over 100 years and it is due for one. The Hyperloop is one such solution that promises to be additive to all existing forms of transportation and will integrate seamlessly into the existing transportation ecosystem.
The Hyperloop was proposed by Elon Musk, CEO of SpaceX/Tesla in a white paper in 2013, as a replacement to the California High Speed Rail.
(1)Hyperloop Transport Concept - 3D Animation Video
(1)The Science of Hyperloop - 3D Animation Video
