Curtis turbine, Rateau turbine, or Brown-Curtis turbine are impulse type turbines. The difference of the two the initial and final heat contents represents the heat energy converted into kinetic energy. As the steam passes through alternate sets of fixed and revolving blades, it constantly expands as it moves along. Lowering the pressure at the suction side can induce. A Curtis stage impulse turbine is shown in Fig. The direction of steam flow is radial and axial to the turbine wheel.
Its modern manifestation was invented by in 1884. This high-velocity steam hit the properly shaped turbine blade, as a result, the steam flow direction is changed. Although all modern turbines are basically impulse-reaction turbines partial expansion taking place in a nozzle , but are designated as reaction turbines. To reduce this risk, considerable efforts are spent to balance the turbine. The deaerator is part of the feedwater heating system.
An overview of all the main types of energy we use fossil fuel, renewable, and nuclear , with some interesting hands-on activities doing a home energy audit, cleaning up an oil spill, making a battery to reinforce the concepts. An impulse turbine, steam produced only impulsive force to the blades. How do you explain something as complex as a turbine to a young child? The large length of low-pressure blades imposes special requirements on stiffness in addition to aerodynamic shaping. Various types of blading arrangements have been proposed, but all are designed to take advantage of the principle that when a given mass of steam suddenly changes its velocity, a force is then exerted by the mass in direct proportion to the rate of change of velocity. This steam is in a partially condensed state point F , typically of a quality near 90%.
The tangential velocity of the blade near the hub is much smaller than at the blade tip, while the axial through-flow velocity is maintained nearly constant. During normal operation in synchronization with the electricity network, power plants are governed with a five percent. These coatings are often stabilized -based ceramics. Pressure compounding involves dividing up of the whole pressure drop from the steam chest pressure to the condenser pressure into a series of smaller pressure drops across the several stages of impulse turbine. The high-velocity steam from fixed nozzles impacts the blades, changes its direction, which in turn applies a force. The change of momentum produces the impulse force.
A set of stationary blades is fixed to the casing and a set of rotating blades is linked to the shaft. Instead of steam, they're driven by a mixture of the air sucked in at the front of the engine and the incredibly hot gases made by burning huge quantities of kerosene petroleum-based fuel. In fact, a series of velocity-compounded impulse stages is called a pressure-velocity compounded turbine. The steam must be reheated in order to avoid damages that could be caused to blades of steam turbine by. In a pump, you have a spinning paddle wheel that sucks water in through one pipe and throws it out from another so you can move water or another liquid from one place to another.
The rotor blades are usually designed like an impulse blade at the rot and like a reaction blade at the tip. This next diagram shows the rotational force of the impulse turbine: From the above diagram of the impulse turbine we see: 1 The steam enters from a fixed nozzle. Impulse Turbine An impulse turbine is a type of steam turbine where the rotor derives its rotational force from the impact force, or the direct push of steam on the blades. Seals: Carbon-ring and labyrinth shaft seals are located at the end of each casing along the rotor. Most other naval forces either retired or re-engined their steam-powered warships by 2010.
These devices are used to minimize the outward leakage of steam under pressure and the inward leakage of air. In most of the cases, maximum number of reheats employed in a cycle is 2 as the cost of super-heating the steam negates the increase in the work output from turbine. Figure 1: Schematic of an impulse stage with velocity diagrams. The method of pressure-velocity compounding is used in the Curtis turbine. The saturated steam leaves the steam generator through a steam outlet and continues to the main steam lines and further to the steam turbine. During such operation, bypass valves are opened and live steam is introduced into the later stages of the turbine.
The steam may or may not be admitted to the whole circumference. A generator or other such device can be placed on the shaft, and the energy that was in the steam can now be stored and used. This implies lower mass flow rates compared to gas turbines. From the last ring of the stage it exhausts into the next nozzle ring and is again partially expanded. The selection of the proper turbine is a very critical issue and an expert people in engineering can take the right decision only. In this turbine steam produces both impulsive and reactive force. Decreasing the turbine exhaust pressure increases the net work per cycle but also decreses the vapor quality of outlet steam.