Impulse and reaction blades are two types of turbine blade designs used in steam and gas turbines. Impulse blades convert the thermal energy of steam or gas into mechanical energy by directing the flow onto the blades, causing them to spin. Reaction blades, on the other hand, create lift through the pressure difference generated by the fluid flow over their shape, relying on both the pressure and the velocity of the fluid. Together, these blade types optimize turbine efficiency and performance in energy conversion applications.
In the impulse turbines the moving blades and nozzle are in series. In the reaction turbines, the blades are fixed.
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.
The difference between impulse and reaction turbine goes here...... 1) In case of an impulse turbine the pressure remains same in the rotor or runners, but in case of reaction turbine the pressure decreases in runners as well as stators also. 2) In case of impulse turbine the pressure drop happens only in the nozzle part by means of its kinetic energy. In case of Reaction one the stators those are fixed to the diaphragm act as a nozzle.
In an impulse turbine, the water (or steam) hits the blades and continues almost straight through as in a jet engine. In a reaction turbine, the water hits a semicircular cup and is completely reversed in path, normally dropping down the center with little or no momentum left. These are rarely used with gases because of having to get the output out of the way, but they work especially well with water at lower pressure as when the dam supplying the water is not very high. Both kinds are used in various situations. in impulse turbine steam expanded in nozzle only because blades have equal cross section area.but in case of reaction turbines blades having diverging or converging areas so steam expansion take place not only on nozzles but also on blades. ravi mehrotra srmcem, lucknow
In an impulse turbine, the water (or steam) hits the blades and continues almost straight through as in a jet engine. In a reaction turbine, the water hits a semicircular cup and is completely reversed in path, normally dropping down the center with little or no momentum left. These are rarely used with gases because of having to get the output out of the way, but they work especially well with water at lower pressure as when the dam supplying the water is not very high. Both kinds are used in various situations. in impulse turbine steam expanded in nozzle only because blades have equal cross section area.but in case of reaction turbines blades having diverging or converging areas so steam expansion take place not only on nozzles but also on blades. ravi mehrotra srmcem, lucknow
Reaction
only moving blades
No, an impulse turbine does not make use of a draft tube. In impulse turbines, the water is directed through nozzles to create high-velocity jets that strike the turbine blades, causing them to spin. Since the pressure is atmospheric at the exit of the turbine, a draft tube is not required to recover pressure or energy, as it is in reaction turbines.
stopping a reaction
only moving blades
Reaction turbines are generally more efficient than impulse turbines because they convert both the kinetic and pressure energy of the fluid into mechanical energy. In a reaction turbine, the water flows through the blades, creating lift and allowing for continuous energy transfer as the fluid expands and loses pressure. In contrast, impulse turbines rely solely on the momentum of the water jets, leading to energy losses during the conversion process. Additionally, reaction turbines can operate effectively across a wider range of flow conditions, optimizing their performance.
The blades impart a downward impulse to the air and produce a downward change in the momentum of the air. The air at the same time exerts an upward impulse on the blades, providing lift. (Newton's third law applies to impulses as well as forces.)