CONDICIONES DE ESTETICA Y DE COMPOSICION Artículo 279.—Aplicación y reglas generales

i) Absolute velocity of water at inlet of runner ii) Velocity of whirl at inlet

iii) Relative velocity at inlet iv) Runner blade angles

v) Width of the runner at outlet

vi) Mass of water flowing through the runner per second vii) Head at the inlet of the turbine

viii) Power developed and hydraulic efficiency of the turbine.

5.124) An inward flow reaction turbine having an overall efficiency of 80% is

required to deliver 136 kW. The head H is 16 m and the peripheral velocity is 3.3 √H. The radial velocity of flow at inlet is 1.1√H. The runner rotates at 120 rpm. The hydraulic losses in the turbine are 15% of the flow available energy. Determine (i) diameter of the runner, (ii) guide vane angle, (iii) the runner blade angle at inlet and (iv) the discharge through the turbine. [AU, Nov / Dec - 2010]

5.125) In an outward flow reaction turbine, the internal and external diameters are 2m

and 2.7m respectively. The turbine speed is 275rpm and the water flow rate is 5.5m3/s. The width of the runner is constant at the inlet and outlet and equal to 250mm. The head acting on the turbine is 160m. The vanes have negligible

thickness and the discharge at the outlet is radial. Determine the vane angles and velocity of the flow at inlet and outlet. [AU, Nov / Dec - 2012]

5.126) In a hydroelectric station, water is available at the rate of 175m3/s under head

of 18m. The turbine run at a speed of 150 rpm, with overall efficiency of 82%. Find the number of turbines required, if they have the maximum specific speed of 460.

[AU, Nov / Dec - 2005]

5.127) A radial flow impeller has a diameter 25 cm and width 7.5 cm at exit. It

delivers 120 liters of water per second against a head of 24 m at 1440 rpm. Assuming the vanes block the flow area by 5% and hydraulic efficiency 0.8, estimate the vane angle at exit. Also calculate the torque exerted on the driving shaft in the mechanical efficiency is 95% [AU, Nov / Dec - 2003] 5.128) A 50m/s velocity jet of water strikes without shock, a series of vanes moving at

15m/s. The jet is inclined at an angle of 20° to the direction of motion of vanes. The relative velocity of jet at outlet is 0.9 times of the values at inlet and the absolute velocity of water exit is to be normal to the motion of vanes. Determine the vane angle at entrance and exit. Also determine work done on vanes per second N of water supplied by the jet. [AU, April / May - 2005]

5.129) In an inward radial flow turbine, water enters at an angle of 22° to the wheel

tangent to the outer rim and leaves at 3 m/s. The flow velocity is constant through the runner. The inner and outer diameters are 300 mm and 600 mm respectively. The speed of the runner is 300 rpm. The discharge through the runner is radial. Find the

(i)Inlet and outlet blade angles.

(ii) Taking inlet width as 150 mm and neglecting the thickness of the blades, find the power developed by the turbine. [AU, April / May - 2010] 5.130) The velocity of the whirl at the inlet to the runner of an inward flow reaction

turbine is 3.15√H m/s and the velocity of flow at inlet is 1.05√H m/s. The velocity of whirl at exist is 0.22√H m/s in the same direction as at inlet and the flow at exist is 0.83√H m/s, where H is head of water 30m. The inner diameter of the runner is 0.6 times the outer diameter. Assuming hydraulic efficiency of 80%. Compute angles of the runner vanes at inlet and exist. [AU, April / May – 2003, 2010]

5.131) Design a Francis Turbine runner with the following data: Net head = 70m

speed N = 800 rpm. Output power 400 Kw Hydraulic efficiency = 95% Overall efficiency = 85% Flow ratio = 0.2 Breadth ratio = 0.1 Inner diameter is 1/3 outer diameter. Assume 6% circumferential area of the runner to be occupied by the thickness of the vanes. The flow is radial at exit and remains constant throughout.

[AU Nov / Dec - 2008] 5.132) The following data is given for a Francis Turbine Net head = 60m speed N =

700 rpm. Shaft power 294.3 Kw Hydraulic efficiency = 93% Overall efficiency = 84% Flow ratio = 0.2 Breadth ratio = 0.1 Inner diameter is 1/2 outer diameter. Assume 5% circumferential area of the runner to be occupied by the thickness of the vanes. Velocity of flow is constant at inlet and outlet and discharge is radial outlet. Determine [AU, Nov / Dec - 2012]

 Guide blade angle

 Runner vane angle at inlet and outlet  Diameter of the runner at inlet and outlet  Width of the wheel at inlet

5.133) The inner and outer diameters of an inward flow reaction turbine are 50 cm

and 100 cm respectively. The vanes are radial at inlet and discharge is also radial.

The inlet guide vanes angle is 10°. Assuming the velocity of flow as constant and equal to 3 m/s, find the speed of the runner and the vane angle at the outlet.

[AU, April / May - 2008] 5.134) A reaction turbine works at 450rpm under a head of 120metres. Its diameter at

inlet is 120cm and the flow area is 0.4m2_{. The angles made by absolute and relative}

velocities at inlet are 20° and 60° respectively with the tangential velocity.

Determine the

 Volume flow rate  Power developed

 Hydraulic efficiency. [AU, Nov / Dec - 2007]

5.135) A turbine is to operate under a head of 25m at 200rpm. The discharge is

9cumec. If the efficiency is 90%, determine the i) Specific speed of the turbine

ii) Power generated iii) Type of turbine

5.136) A Francis turbine with overall efficiency of 75% is required to produce

149.26kN. It is working against a head of 7.62m. The peripheral velocity is 0.26√(2gH) and the radial velocity of flow at inlet is 0.96√(2gH). The wheel runs at 150rpm and the hydraulic losses in the turbine account for 22% of the available energy. Assume radial discharge; determine the guide blade angle, the wheel vane angle at inlet, diameter of the wheel at inlet and width of the wheel at inlet.

[AU, May / June – 2009, 2013]

5.137) A Francis turbine with overall efficiency of 76% and hydraulic efficiency of

80% is required to produce 150kW. It is working against a head of 8m. The peripheral velocity is 0.25√(2gH) and the radial velocity of flow at inlet is 0.95√(2gH). The wheel runs at 150rpm. Assume radial discharge; determine the guide blade angle, the wheel vane angle at inlet, diameter of the wheel at inlet and width of the wheel at inlet. [AU, Nov / Dec – 2009, April / May - 2010]

5.138) A dam on a river is being sited for a hydraulic turbine. The flow rate is 1600

m3_{/h, the available head is 25 m, and the turbine speed is to be 460 rpm. Discuss}

the estimated turbine size and feasibility for a Francis turbine; and a Pelton wheel. [AU, Nov / Dec - 2011]

5.139) A turbine is to operate under a head of 25m at 200rpm. The discharge is 9

cumec. If the efficiency is 90%, determine the performance of the turbine under a head of 20 meters. [AU, Nov / Dec - 2007]

5.140) A reaction turbine works at 450 rpm under a head of 120 m. Its diameter at

inlet is 120 cm and the flow area is 0.4 m2_{. The angles made by the absolute and}

relative velocity at inlet are 20° and 60° respectively, with the tangential velocity. Determine the volume flow rate, the power developed and the hydraulic efficiency.

[AU, Nov / Dec - 2007] 5.141) Calculate the diameter and speed of the runner of a Kaplan turbine

developing6000 kW under an effective head of 5 m. Overall efficiency of the turbine is 90% and the diameter of the boss is 0.4 times the external diameter of the runner. The turbine speed ratiois 2.0. And flow ratio is 0.6. [AU, Nov / Dec - 2006]

5.142) A Kaplan turbine runner is to be designed to develop 7357.5kW shaft power.

The net available head is 5.50m. Assume that the speed ratio is 2.09 and flow ratio is 0.68, and the overall efficiency is 60%. The diameter of the boss is 1/3rd _{of the}

diameter of the runner, its specific speed. [AU, May / June - 2009]

5.143) A Kaplan turbine runner is to be designed to develop 7360kW. The net

available head is 5.5m. Assuming the speed ratio is 2.09 and the flow ratio is 0.68 and the overall efficiency is 60%. The diameter of the boss is one third of the diameter of the runner. Find the diameter of the runner, its speed and its specific speed. [AU, Nov / Dec - 2009]

5.144) A Kaplan turbine working under a head of 20 m develops 15 MV brake power.

The hub diameter and runner diameter of the turbine are 1.5 m and 4 m

respectively. The guide blade angle at the inlet is 30°. The discharge is radial. Find the runner vane angles and turbine speed.

[AU, April / May - 2010, Nov / Dec - 2011]

5.145) A Kaplan turbine is to be designed to develop 9100kW. The net available head

is 5.6m/ If the speed ratio is 0.68, overall efficiency 86% and the diameter of the boss is 1/3 the diameter of the runner. Find the diameter of the runner, its speed and specific speed of turbine. [AU, April / May - 2011]

5.146) A Kaplan turbine delivers 10 MW under a head of 25 m. The hub and tip

diameters are 1.2 m and 3 m. Hydraulic and overall efficiencies are 0.90 and 0.85. If both velocity triangles are right angled triangles, determine the speed, guide blade-outlet angle and blade outlet angle. [AU, Nov / Dec - 2013]