Question

Explain about the analysis of turbine blades.

Chapter 10. Design of Turbine 10.3 Analysis of Turbine Blades Geusor 10.3.1 Basic Analysis Veke us НРГ ) Basic Blade Analysis VNozzle Kinetic E Thermal E Blade Kinetic E , Mechanical work 23 (K.E delivered to the blade) (Energy entered) - (Energy leaving) 2g. 2ge Max. KE delivered There is one blade speed for a specific nozzle velocity ul at which v2 is perpendicular to ub 24

Answer 1

- work is obtained due to change in angular momentum of the fluid entering to the turbine blades which generates torque. To obtain maximum work it is desirable to get fluid leaving to the blades in the reverse direction of entry. Which is practically not possible to get exact 180degree reverse of fluid due to movement of blade at the same time.

- fluid enters the blades having some energy but as we are getting the work by change in momentum so for that pressure energy(thermal) of fluid is converted into kinetic energy using nozzle or sometimes guide vanes of converging cross section. This fluid carry kinetic energy at the time of entry to the blades.

- Mechanical work can also be written as change in energy of fluid by difference of change in initial kinetic energy and final kinetic energy of fluid leaving.( Change of momentum equation also give change in kinetic energy by some manipulation)

-By the equation of change in kinetic energy it can be concluded that to get maximum work inlet velocity (V1)of fluid should be high but velocity leaving(V2) to the blades should be minimum.

B lade Vn that tuo wにVw2 emo wea Vw2 should ba guno o w to be o, v; sh ould be Pexpendiaular to blade wloci