Matching of Machine with Resource/Demand P M V Subbarao Professor Mechanical Engineering Department A Response time Based Parameter….

Machine-Fluid Matching Parameter: For compressible power consuming fluid machines For incompressible power consuming fluid machines

Selection of Speed of A Turbo Machine The impact of Nationalism…….

Importance of Specific Speed A pump with a given flow geometry and momentum transfer principle

Selection of Geometry Vs Specific Speed Specific Speed

Speed Vs Size : Constant Head & Flow Rate N=1000 rpm N=1500 rpm N=3000 rpm Demand Speed n f = 492 rps

Matching of a Hydraulic Turbine to a hydraulic Resource Speed: N (rpm) or n (rps) This is named as Specific Speed, N s

Popular Definitions for Hydraulic Machines The specific speed, usually represented by N s, also denominated absolute specific speed or specific angular speed.

Specific Speed

Blade Geometry Vs Characteristic of Resource

The Pelton Wheel : Pure Impulse Turbine

Micro classification Based on Specific Speed

MORE ADAPTED TYPE OF TURBINA IN FUNCTION OF THE SPECIFIC SPEED. Specific Speed in r.p.m.Turbine typeJump height in m Until 18Pelton of an injector800 From 18 to 25Pelton of an injector800 to 400 From 26 to 35Pelton of an injector400 to 100 From 26 to 35Pelton of two injectors800 to 400 From 36 to 50Pelton of two injectors400 to 100 From 51 to 72Pelton of four injectors400 to 100 From 55 to 70Very slow Francis400 to 200 From 70 to 120Slow Francis200 to 100 From 120 to 200Normal Francis100 to 50 From 200 to 300Quick Francis50 to 25 From 300 to 450Extra-quick Francis25 to 15 From 400 to 500Extra-quick helix15 From 270 to 500Slow Kaplan50 to 15 From 500 to 800Quick Kaplan15 to 5 From 800 to 1100Extra-quick KaplanLess than 5 P in hp & H in meters

Further Utility of Specific Speed in Hydro-power Industry Every nation has a public sector organization to identify and quantify the hydro resources. (NHPC in India) This organization will also announce the developmental plans. The data will be made available on public domain. Turbine manufactures will collect the data and develop a suitable turbine design with highest possible efficiency. Every industry will have in house testing facility to experimentally test the design and show performance guarantee.!!!!!

Sharavathi Catchment Area

Jog Falls

Sharavati Generating Station Capacity:1035 MW. Head available: 443 m Site Specific Speed: 0.776×N rpm Selection of Turbine WheelSpecific Speed (rpm) Pelton 10 – 30 Turgo 20 – 70 Crossflow 20 – 200 Francis 30 – 400 Propeller and Kaplan

Hydro-power Manufacturing Industry Turbine manufactures will collect the data and develop a suitable turbine design with highest possible efficiency. Every industry will have in house testing facility to experimentally test the design and show performance guarantee.!!!!!

How to Simulate a Natural Resource in the Laboratory? Compute specific speed of the resource, with a suitable machine speed as: Redefine specific speed as, the speed of a turbine similar to which you want to propose would give (of equal form but reduced dimensions), which, installed in a fall of 1 m height, would provide a power of 1 hp

DIMENSIONAL ANALYSIS Scale model to prototype design and analysis. Used to select proper turbo-machine (axial, radial or mixed flow,…) Used to define performance parameters