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Francis turbine has H=30 m, D1=1.2 m inlet and D2= 0.6 m at outlet. Guide blade angle is 15$^{\circ}$ and vane angle at inlet 90$^{\circ}$, water at exit leaves vanes without tangential

velocity and velocity of flow is constant. Assume number of frictional classes. find speed of wheel and vane angle at exit

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Given:-

H=30m

$D_{1}$=1.2 m

$D_{2}$=0.6 m

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Guide blade angle $\alpha=15^{\circ}$

inlet vane angle $\Theta =90^{\circ}$

i.e $Vr_{1}=vf_{1} and Vw_{1}$=0

$vw_{2}$=0

$vf_{1}=vf_{2}=vf$

enter image description here

speed of whee, Nand vane angle $\phi$ at exit

$u_{1}vw_{2}=v_{1}cos\alpha=v_{1}cos/5$

$vf_{1}=v_{1}sin \alpha=vf_{2}=v_{2}$

$vf_{1}=vf_{2}=v_{2}=v_{1}sin/5$

H=$\frac{Vw_{1.u_{1}}}{g}+\frac{V_{2}^{2}}{2g}$

30=$\frac{V_{1}cos 15\times V_{1}cos15}{9.81}+\frac{(v_{1}sin15)^{2}}{2\times 9.81}$

$\Theta=\tan^{-1}\frac{Vf_{1}}{BD}=tan^{-1}(\frac{2.15}{0.093})=87.52^{\circ}.....$

$\Theta=tan^{-1}\frac{vf_{2}}{u_{2}}=tan^{-1}(\frac{2.15}{6.05})=19.564^{\circ}...ans$

$v_{2}=vf_{2}$=2.15m/s

ii) Head at inlet of turbine H:

H=$\frac{vw_{1}}{9}+\frac{v^{2}_{2}}{29}=\frac{12.193\times …

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