Take: Ideal gas constant R = 287 J/kg-K, Density of water p = 1000 kg/m3, Acceleration due to gravity, g = 9.81 m/s2. (a

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Take Ideal Gas Constant R 287 J Kg K Density Of Water P 1000 Kg M3 Acceleration Due To Gravity G 9 81 M S2 A 1 (68.03 KiB) Viewed 18 times

Take: Ideal gas constant R = 287 J/kg-K, Density of water p = 1000 kg/m3, Acceleration due to gravity, g = 9.81 m/s2. (a) Explain the term Specific Speed. What is its purpose? (b) In a laboratory experiment, water at 39.24 kPa is available to operate a model turbine at 413.32 rpm. What type of turbine will you choose if it is to have an output power of 30 kW? (c) A geometrically similar prototype turbine is required to be designed to produce 20 MW under a head of 16 m under dynamically similar conditions. At what speed will the prototype run? What should be the vane diameter ratio between the prototype and model? What will be the volumetric flowrate through the prototype assuming its efficiency is 90%? Table 1: Specific speeds and corresponding turbines most suitable for the application Type of Turbine Pelton wheel with 1 nozzle Pelton wheel with 2 nozzles Pelton wheel with 4 nozzles Francis turbine, low-speed Francis turbine, normal Francis turbine, high-speed Francis turbine, express Propeller and Kaplan turbines No 1. 2. 3. 4. 5. 6. 7. 8. Specific speed 4 to 35 17 to 50 24 to 70 80 to 120 120 to 220 220 to 350 350 to 430 300 to 1000