10-12-2012, 03:21 PM
PRESENTATION ON : TURBINE
TURBINE.pptx (Size: 1.89 MB / Downloads: 43)
INTRODUCTION
The device in which the kinetic ,potential or
intermolecular energy held by the fluid is
converted in the form of mechanical energy
of a rotating member is known as a turbine .
Also , defined as all machines in which hydraulic energy
is transferred into mechanical energy (in the form of
rotating shaft ) ,or in some other moving parts are
known as ‘turbines’ or hydraulic motors.
TURBINE:
.A simple design of a turbine contain as rotor assembly, which is the moving part, having shaft or drums with blades attached to them. The movement of the blades, which is caused by the flow of fluids, creates rotational energy which is imparted to the rotor. Some example of turbine impulse , Reaction etc.
Theories of operations of turbines
A flowing or working fluid contains kinetic as well as potential energy and the fluid may be compressible as well as incompressible. The energy of these fluids is trapped by turbines in several ways. Impulse turbines- The impulse generated by changing the direction of flow of high velocity fluid or gas jet is used to spin the turbine. This leaves the fluid flow with a decreased amount of kinetic energy. The fluid or gases in the turbine blades have no pressure change and the entire pressure drop takes place in the stationery blades. The fluid is accelerated using a nozzle, which changes its pressure head to velocity head. This is done before the fluid reaches to turbine. The transfer of energy in impulse turbines is described by Newton’s second law of motion.
Reaction turbines-
A torque is developed in these turbines when they react to the gas or the fluid pressure or the mass. When the gas or fluid passes through the turbine rotor blades, the pressures in the system changes. The turbine must be fully immersed in the flowing fluid and the pressure casement is also provided for a working fluid. The primary function of the working fluid is to contain and direct the working fluid. It also maintains the functions imparted by the draft tubes in water turbines. This concept is used in most steam turbines including the Francis turbine. Newton’s third law is used to describe the transfer of energy in reaction turbines.