water turbine

Help me with engine

hey i am in 3rd year mechanical engineering, i want to design such an engine in which we used COMPRESSED AIR as a working fluid, if you have any suggestion then please tell me. Thankyou

Re: Help me with engine

syed waqas

hey i am in 3rd year mechanical engineering, i want to design such an engine in which we used COMPRESSED AIR as a working fluid, if you have any suggestion then please tell me. Thankyou

It should me therefor perfectly air tight and enough thick[over pressure may result in bursting] mate

Re: Help me with engine

syed waqas

hey i am in 3rd year mechanical engineering, i want to design such an engine in which we used COMPRESSED AIR as a working fluid, if you have any suggestion then please tell me. Thankyou

if u wanna use compressed air alone as working fluid, well u will have to make a huge compressor which can compress air to posses that much of energy and not only that we should have air tight compartments.

though it is a renewable source , for running a huge compressor we need a lot of fuel !

In many cases compressed air is used in combustion process along with the fuel, but using it alone will be a bit difficult.

The idea to run a water turbine by using the jet from a hydraulic cylinder seems workable upto an extent.

The diameters of the two Hydraulic cylinders 20cm and 2cm respectively suggest that the larger cylinder can be used to transmit greater force on the lower cylinder with the application of a much smaller pressure, provided the cylinders are interconnected by some kind of rod or piston attatched to the base of the first one to the head of the other.

The movement of the top piston by 1mm produces an extension of 3cm ie 30mm in the lower piston. This indicates that the hydralics have amplified the energy transmitted by a ratio of 1:30 if the hydraulic fluid used are the same.

To place a turbine inside the lower cylinder seems impractical because the diameter of the lower cylinder is only 2cm, and what power can a turbine wheel with a diameter of 2cm produce. Actually the diameter will be less than 2cm as there has to be some clearence between the barrel and the turbine wheel.

It is also not easy to machine or fabricate a complete turbine wheel with blades of the order of such small dimensions. Even if we hypothetically assume to have such a miniature turbine made how much power would it generate. And would the shaft ( which would be even smaller in diameter) sustain the load and continue to rotate.

Also the turbine being placed inside the cylinder would cause a resistance (frictional and vortices) to the fluid itself. Also the viscosity of the fluid would produce resistance to the rotation of the turbine within its own environment. This would reduce the efficiency of the turbine and any power produced.

Also the set up described implies that the turbine would be rotated intermittently and not continously, so the generation if any would not be continous.

These are the practical problems in having a turbine of the desired dimensions and placement to be used in reality.

However, we can have a different approach to this. We can make an arrangement such as to use another liquid, say water for simplicity of working, to be forced by the lower cylinder to form a jet. This jet can be used to impact on the blades of a specially designed turbine at a siutable angle of attack.
This will rotate the turbine wheel with sufficent energy as the jet would be high velocity and hence produce measurable amount of energy though not high.

The turbine shaft can be attatched to a small dynamo and electric power can be generated. The voltage can be used to charge a battery of suitable rating.


We can use a convergent nozzle attatched to the lower cylinder with water supplied to it and a piston or a disc from the lower cylinder to force the water to form a high velocity jet.

There has to however be a system to relinquish water supply to the nozzle tube during the two consecutive operations of the cylinders.

The turbine in this situation can be of much larger dimensions than the previous conditions. Hence it can be easier to manufacture the turbine and the componenets especially the blades and a stronger shaft with proper mounting.

Also the power generated by the turbine will be considerable, as we can have a minimum of 10-12 cm diameter wheel easily. The detalied calcuations along with the dimensions will yield the actual values of the diameter of the turbine, the shaft and the jet velocity and hence the power that can be produced from such a system.

Hence if the turbine is placed outside the lower cylinder and a jet using the hydraulic power from the cylinder inturn runs the turbine then there can be power generated from the arrangement given if the existing system is to utilised to produce electricity.

Re: Help me with engine

Yeah Power utilized will be more and inital cost will be high mate...