Relationship Between Power and Various Efficiencies Refer figure shows the input power to runner and output power, Po from generator, Let H, Q = Discharge, (m3/s)              ρ = Density of water = 1000 kg/m3 Input Power Pi = ρ.g.Q.H/1000 (kW) Mechanical Efficiency, ηm ηm = Shaft power available from runner, Ps/ Input power, Pi Generator efficiency, … Read more

Classification and Selection of Hydraulic Turbine Basically the turbines are classified as impulse and reaction turbines as discussed earlier. However, their further classification and selection is based on several ground data including the availability of head, discharge, specific speed etc as follows : 1) According to Head and Quantity of Water Available : Table A … Read more

Performance of Water Turbines Water turbines are designed to work under given head, discharge and output at certain speed. However, the turbine may be needed to work under such operating conditions which are different than designed values. Therefore, the performance testing of turbines becomes very essential to evaluate its characteristics. Also, it is essential to … Read more

Types of Surge Tank A surge tank can be used to control the surge or sudden pressure changes in a pipe line which may be due to following : Sudden closure and opening of valves. At the time of starting or stopping the turbine. Closure of turbine gates during the governing operation of turbines. Main … Read more

Governing of Turbines The load on the generator keeps on fluctuating while the input power to the turbine is constant. Therefore, the speed of turbine will either increase or decrease with the decrease or increase of load respectively. This leads to fluctuation of speed of the turbine. This in turn will fluctuate the speed of … Read more

Axial Flow Reaction Turbines Propeller and Kaplan Turbines The propeller and kaplan are propeller shaped axial flow reaction turbines in which the water flows parallel to the axis of the shafts. These turbines were developed to meet the requirement of using available large quantity of water at low heads (upto 80 m). In the year … Read more

Types of Draft Tubes in Hydro Power Plant Though there are various types of draft tubes, but the important type of draft tubes are : Conical draft tube Simple elbow draft tube Elbow draft tube with circular inlet and rectangular outlet Moody’s spreading draft tube. (1) Conical draft tube : Earlier designs of draft tubes … Read more

Comparison Between Impulse Turbine and Reaction Turbine Sr. No. Impulse Turbine Reaction turbine 1. It works on the principle of impulse. Therefore, it follows the impulse momentum equation. It works on the principle of impulse and reaction. Therefore, it follows the law of angular momentum. 2. All the available head is first converted into kinetic … Read more

Francis Reaction Turbines A francis reaction turbine is shown in Figure A. The main components of a reaction turbine are : Scroll casing Runner and shaft Guide mechanism Draft tube Figure A (1) Scroll casing : Water from penstock flows into the outer scroll casing of turbine which is made in spiral shape. The casing … Read more

Construction and Working of Pelton Wheel An arrangement of Pelton turbine is shown in Figure A. Figure A The water from reservoir flows through the penstock to the nozzle which converts the pressure energy (high head of water) into kinetic energy. The resultant high velocity jet from nozzle strikes the buckets or vanes fitted at … Read more