HOW DOES THE OUTWARD FLOW REACTION TURBINE WORKS ?


 OUTWARD FLOW REACTION TURBINE
On the previous blog we discussed about the Reaction turbines. Today we are going to discuss about how the Reaction turbine works.
Reaction turbine consists of a shaft, a cylindrical disc and vanes or blades or buckets on its outer perimeter as shown in the figure:
                                        
                                               FIG: 1
Moving water flows through the centre at inlet of the wheel and then travels radially through the guide vanes and finally it flows over the moving vanes. Once have the look carefully at the figure shown IN FIG: 1.
                                                           FIG: 1
As the water enters into the wheel and firstly it will glide through the moving vanes before passing through the moving vanes. So the main purpose of providing guide vanes is to direct the water into the correction direction as enters the moving vanes.   As the water moves along the water vanes, the moving water creates or exerts the thrust on the wheel, which will in return rotate the wheel. The wheel may be provided below or above the tail race. The main point to keep in mind while operating the Reaction turbine is that wheel must run full as water is constantly under pressure.
The relative velocity of water is increased in the outer direction because the centrifugal force is developed due to the turning of the water as the wheel turns. This increases the rate of flow and energy supplied also increases. This causes the increase in the speed of the wheel. Due to this centrifugal head further increases and wheel tends to race. This can be taken as one of the disadvantage while using the Reaction turbine because controlling the speed becomes difficult. For more detail refer to the figure.
Let’s have clear look at the working of the turbine. Suppose XY is one the vanes of the reaction turbine. Here, X is to be taken as the inlet and Y is to be taken as the outlet point of the vane XY. Now suppose ‘a’ is the periphery velocity of the wheel at the inlet of the vane XY and similarly ‘a1’ is the periphery velocity of the wheel at the outlet of the vane XY.  Now the periphery velocity ‘a’ is tangential or along the tangent through the point of inlet of vane XY at point X. similarly the periphery velocity ‘a1’ is along the tangent through the point of the outlet of vane XY at point of Y. Hence, when looking at the figure provided below (FIG: 2, Fig: 3 and Fig: 4) it is clearly seen that velocity direction at the points X and Y are not in the same direction. But in the next figure, their directions are taken into the same direction for the sake of convenient.
   
                                               
                                                             Fig: 2


                                          
                                                                Fig: 3

             
                  
                                                 Fig: 4
Here,
a= periphery velocity of the wheel at inlet at point X
a1= periphery velocity of the wheel at outlet at point Y
b= relative velocity of wheel at inlet X
b1= relative velocity of wheel at outlet Y
v =absolute velocity of water at point X
v1= absolute velocity of water at point Y
c= velocity of water flow at X
c1= velocity of water flow at point of outlet of vane XY at Y
e= velocity of whirl at inlet X
e1= velocity of whirl at outlet Y
N= speed of the wheel in rpm
D= inlet diameter of the wheel (runner)
D1= outlet diameter of the wheel (runner)
B= breadth of the wheel at the inlet
B1= breadth of the wheel at the outlet
HOW TO CALCULATE THE DISCHARGE OF THE TURBINE?
Q= radial area at inlet * radial velocity at inlet = radial area at outlet *radial velocity at outlets
      =∏ *D* B *C = ∏* D1*B1*C1
But while calculating the total discharge of the turbine, some space is considered for the blades of the turbines.  4% to 5% of the total space is occupied by the blades of the turbines. So, the total discharge becomes
 Q= 0.95* ∏*D*B*C = 0.95*∏*D1*B1*C1
HOW TO CALCULATE THE HEAD AT THE TURBINE??
H= (p/w) + (v^2/2*g)
Where the first term is the pressure head and the latter term refers to the kinetic head.
HOW TO CALCULATE THE PERIPHERY VELOCITIES OF THE WHEEL??
Periphery velocity at the inlet ‘a’ = (∏*D*N)/60
Periphery velocity at the outlet ‘a1’ = (∏*D1*N)/60
HOW TO CALCULATE THE WORK DONE PER N REVOLUTION OF WATER PER SECOND??
When ‘e’ and ‘e1’ are in the same direction, then,
Required work done= (e * a – e1 * a1) / g
But when ‘e’ and ‘e1’ are not in the same direction, then,
Required work done= (e * a – e1 * a1) / g
                                                                                                        THANK YOU

NOTE: Discrimination and choices are two completely different things. Discrimination may have choices but choices do not have discrimination. It is never my intention to hurt someone's feeling, emotions and pride. Above material is solely just for entertainment purpose only and should be taken light heartedly.
Finally we all are humans. Humans have different physical forms and mental forms and should be respected no matter what. Abusing in any form whether it be verbal, emotional or physical surely is a criminal act that deserves serious attention with punishment. In other hand, jokes and comedy are completely different things which should exist within the circle of loved and near ones and can be extended to some extent beyond the limits but surely we need to be conscious towards the fact that our loved ones are not hurt by our words and actions. Peace, love and respect should not be destroyed to the extent that it becomes impossible to repair or rebuild.



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