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An example of a velocity triangle drawn for the inlet of a turbomachine. The "1" subscript denotes the high pressure side (inlet in case of turbines and outlet in case of pumps/compressors). A general velocity triangle consists of the following vectors: [1] [2] V = absolute velocity of the fluid. U = blade linear velocity.
The image describes the changes in velocity triangles on decreasing the specific speed or decreasing the pressure head, and finally shows the evolution from the Francis hydraulic turbine to the Kaplan hydraulic turbine. Nomenclature of a velocity triangle: A general velocity triangle consists of the following vectors: [1] [2]
Fig-3: Schematic Diagram of Pressure compounded Impulse Turbine. The pressure compounded Impulse turbine is also called a Rateau turbine, after its inventor. This is used to solve the problem of high blade velocity in the single-stage impulse turbine. It consists of alternate rings of nozzles and turbine blades.
With the help of these equations the head developed by a pump and the head utilised by a turbine can be easily determined. As the name suggests these equations were formulated by Leonhard Euler in the eighteenth century. [1] These equations can be derived from the moment of momentum equation when applied for a pump or a turbine.
The velocity triangle [2] (Figure 2.) for the flow process within the stage represents the change in fluid velocity as it flows first in the stator or the fixed blades and then through the rotor or the moving blades. Due to the change in velocities there is a corresponding pressure change. Figure 2. Velocity Triangle for fluid flow in turbine
A velocity compounded impulse turbine is shown in the figure. One-stage velocity-compounded impulse turbine - Curtis Turbine. The decrease in the absolute velocity of the fluid across the two rotor blade rows (R 1 and R 2) is due to the energy transfer; the slight decrease in the fluid velocity through the fixed guide blades (F) is due to ...
An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. ... Velocity triangle. ... When ω is the angular velocity of the turbine, then ...
Usually the flow velocity (velocity perpendicular to the tangential direction) remains constant throughout, i.e. V f1 =V f2 and is equal to that at the inlet to the draft tube. Using the Euler turbine equation, E/m=e=V w1 U 1, where e is the energy transfer to the rotor per unit mass of the fluid. From the inlet velocity triangle,