How are steam turbines designed?
Two basic types of steam turbine designs are available. One is an impulse design in which the rotor turns as a result of the force of steam on the blades. The other is a reaction design, and it operates on the principle that the rotor derives its rotational force from the steam as it leaves the blades.
What aspects of the design of a steam turbine increase efficiency?
How do you increase efficiency in steam turbines? Increasing short blade heights in high-pressure and intermediate-pressure turbines leads to increased capacity and therefore improved efficiency.
What are the factors that affect the performance of steam turbines?
Any pressure, temperature and flow rates changing at the inlet and/or outlet conditions will affect the both turbine isentropic efficiency and thermal efficiency.
What is steam turbine in engineering?
A steam turbine is a device that extracts thermal energy from the steam and converts it to mechanical work on a rotating output shaft. From: Flow and Heat Transfer in Geothermal Systems, 2017.
What are the 3 types of steam turbine?
In order to match steam production to heat demand, there are three types of steam turbine in common use for CHP plants. These three are called a back pressure steam turbine, an extraction steam turbine and a condensing steam turbine. Each type will suit a different configuration of plant.
How do you select a steam turbine?
Steam turbines differ in terms of inlet steam pressure and temperature, exhaust steam pressure, pump power, and pump speed. Speed control is either manual or automatic. Pressure, temperature, and the cleanliness of the cooling water are also important considerations when selecting steam turbines.
What affects turbine efficiency?
A small increase in firing temperature has a significant effect on produced horsepower and on engine efficiency. Gas turbine site power is determined by elevation, temperature, inlet conditions, outlet conditions, humidity, and fuel conditions.
How do you increase the efficiency of a turbine?
Therefore, gas turbine efficiency can be improved by cooling the inlet air. This is especially effective in hot, dry climates. A significant benefit of turbine air inlet cooling is that it can reduce (or eliminate) fuel efficiency reduction by evaporative cooling the inlet air to the wet bulb temperature.
What are the main components of steam turbine?
The main parts of a steam turbine are (1) the rotor that carries the blading to convert the thermal energy of the steam into the rotary motion of the shaft, (2) the casing, inside of which the rotor turns, that serves as a pressure vessel for containing the steam (it also accommodates fixed nozzle passages or stator …
What is principle of steam turbine?
In simple terms, a steam turbine works by using a heat source (gas, coal, nuclear, solar) to heat water to extremely high temperatures until it is converted into steam. As that steam flows past a turbine’s spinning blades, the steam expands and cools.
How do you size a steam turbine?
Calculation Details
- Step 1: Determine Inlet Properties.
- Step 2: Calculate Ideal Outlet Properties (Inlet Entropy equals Outlet Entropy)
- Step 3: If solve for ‘Isentropic Efficiency’, Determine Outlet Properties.
- Step 3: If solve for ‘Outlet Properties’, Determine Outlet Specific Enthalpy.
Why is steam turbine efficiency so low?
The overall Steam Turbine Efficiency is quite low (about 29%) due mainly to two reasons. Firstly, a huge amount of heat is lost in the condenser and secondly heat losses occur at various stages of the plant. The heat lost in the condenser, cannot be avoided.
Which turbine gives highest efficiency?
Kaplan
Among the following which turbine has highest efficiency? Explanation: Kaplan is inward flow reaction turbine and is operated under head less than 60 meters. The vanes attached to hub are adjustable and Kaplan is mainly operated in location where large quantity of water at low head is available.
How do you calculate steam turbine efficiency?
Calculate steam turbine efficiency by dividing the theoretical pounds per hour of steam by the steam actually consumed. This is 44,855.58 pounds (theoretical) / 52,462 pounds actual = 0.855 or 85.5 percent operating efficiency.
What are the 4 main components of a steam power plant?
What are the components of a Steam Power Plant? A furnace, steam turbine, generator, and other auxiliaries make up a steam power station. The boiler produces steam at a high temperature and pressure. The steam turbine is a machine that transforms steam’s heat energy into mechanical energy.
What is the maximum size of steam turbine?
In principle modern technologies allow the design of steam turbines with a unit capacity of up to about 2000 MW – specifically 50 Hz wet steam turbines for nuclear power plants (provided, of course, a nuclear reactor of sufficient power is available).
Why vacuum is required in steam turbine?
Vacuum applies to steam turbines because the pressure of saturated vapour above available cooling water is well below 1 bar (typically 17 mbar at 15°C ambient).
Which turbine is highest speed?
Kaplan turbine
Explanation: The specific speed of Kaplan turbine ranges from 600 to 1000 rpm. It is a low head axial flow turbine. From the table, we can conclude that the Kaplan turbine has the highest specific speed.
What is turbine efficiency formula?
Efficiency (ɳ) = Work Done / Input Kinetic Energy
It is fairly difficult to calculate work done by turbine because of all these factors and in some cases it is not possible to accurately calculate certain factors like velocity, temperature, or pressure of steam.
What is the maximum efficiency of a steam turbine?
Practical thermal efficiency of a steam turbine varies with turbine size, load condition, gap losses and friction losses. They reach top values up to about 50% in a 1,200 MW (1,600,000 hp) turbine; smaller ones have a lower efficiency.
What is working principle of steam turbine?
Why barometric leg is required?
Since the condensate drains by gravity, the barometric leg must be high enough to make sure the condensate does not enter the condenser and flood the lower tubes. If the tubes flood, they will not be able to transfer heat effectively.
Why condenser is kept in vacuum?
A vacuum is maintained in the condenser so that steam can easily flow and more work can be extracted from the steam in the turbine; this is the reason why vacuum is maintained in condensers. Therefore, some methods must exist to initially cause a vacuum to exist in the condenser.
What is height of barometric leg?
As 1″ of Hg equals 1.133 feet of water, a minimum barometric leg of 29.5 feet is required. Note that this is the ‘minimum’ barometric leg height. It’s normally recommended that a 34 foot barometric leg be provided which allows the system to pull a pure vacuum and still allows the water and condensate to drain freely.
How do you calculate barometric legs?
Another equation to barometric leg height calculation is Hc = [(Pman + Pbarometric – Pcondenser)/SGt] x WC. For condensing fluids different than water, barometric leg correction can be done using Hf = Hc x (SGt/SGf), where SGf is the specific gravity of the fluid at the operating temperature in the Condenser.