These impulse turbines are made up of rings of nozzles followed by rings of blades. Ntably, hgh pressure, hgh energy steam is allowed into the nozzles then it is let into a region of lower pressure, hgh velocity in a different direction. A a result, te changing direction and high velocity produce impulsive force that acts in the direction of rotation of the turbines. Tus according to Newtons second law of motion, te rate of change in momentum is directly proportional to the external force producing the change it takes place in the direction of the force (Woodruff 32).
Anotable feature of the Impulse turbine is the presence of fixed nozzles that orient the steam flow into high-speed jets (Wikipedia par. Tese jets contain significantly high kinetic energy which is transferred to the turbine to cause shaft rotation. Adrop in pressure across the stationary blades with a net increase in steam velocity occurs. A a result, a the steam passes through the nozzles its pressure decreases from the inlet as it advances to the exit. A a of the high ratio expansion of the steam, te steam leaves the nozzle at very high velocity and as such, asignificant portion of maximum velocity in the steam leaves to the moving blades.
Frthermore, te law of moment of momentum requires that moments of external forces acting on a fluid occupying the control volume be equal to the net time change of angular momentum flux through the control volume. Te net loss in the energy due to the high exit velocity is commonly termed as carry over velocity useful understanding the operation of the turbine (eHow par.
Te second type of steam turbines based on forces that act on them are the Reaction turbines. Tese turbines primarily apply Newton’s third law of motion that states that for every action force there is always reaction force. These type of turbines are made up of rings of fixed blades to the casing. Arow of blades is tightly mounted on the rotor of the turbine (Woodruff par. Tese blades are shaped in such a way that they provide a narrowing passage behaves like a nozzles.
Terefore, icreasing the velocity of steam it is important to notice that the increase in velocity of steam results in change in direction and an impulsive force is created and therefore the more correct name for this type of turbines is impulse- reaction because the two...
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