CROSS FLOW TURBINE

  Cross flow water turbines refer to rotary engines
designed to acquire energy from the transverse flow
or movement of water.
A.G.M. Mitchell , around 1900, invented cross flow
turbine.
Later around 1916 to 1918,Banki,in a series of
papers , presented his theory of operation and
indicted the efficiency of 80% is attainable  as a
result of his experiment.

DESIGN

vCross-flow water turbines contain a cylindrical runner, or water wheel, connected to a horizontal shaft and made up of as many as 37 blades.
vThe turbine design includes a regulating unit that varies the cross-section flow of water and controls it based on the water available and power level needed.
v A nozzle shoots a jet of water toward the cylindrical runner. The water enters the runner at an approximate 45 to 120 degree angle, enabling kinetic energy produced by the water to be sent to the blades.

WORKING OF TURBINE

The cross flow turbine has a drum like rotor with a solid disk at each end and gutter-shaped rotor blades joining the two disks together.
Water is guided into the rotor by an inlet guide which directs it under pressure through the rotor the first time, through the drums interior transferring some of its momentum, and then through the rotor a second time before exiting the turbine at ambient pressure.
Then the cross flow turbine converts the flow and pressure of the water to mechanical energy. This action results in very little pressure drop across the turbines blades thereby increasing its efficiency.
Due to the angular momentum of the water flowing across the turbine rotor blades, the kinetic energy of the water is converted to a torque at the output shaft which in a small scale hydro power system can be used to drive an electrical generator.
vThen the cross flow turbine turns a generator, which is connected to electrical loads to power a single home, building or a very small installation depending upon the electrical generator used.

ADVANTAGES

Mostly used in Mini and Micro Hydropower production(less than 2,000KW).
Ideal for low head conditions as low as 20 feet of vertical drop (low as 200m) .
Excellent behavior with partial load or low stream flow.
Its construction makes it easier to maintain than other turbine types.
Self cleaning. No runner cleaning is necessary.
No dam required-simple diversion up stream or any water source meeting requirements.
Almost no turbine noise.