Kaplan Turbines

Generally there are two types of axial flow turbine (Axial Flow Turbines), namely Turbine Propeller and Kaplan turbines with a brief description as follows:

Propeller Turbine, Propeller turbine or a turbine where the runner as the completeness of reaction turbines to change the flow of water into round-shaped cylinder with tapered ends. In that section of the plate fin is placed some steel plates (numbered 4-8), called vane or blade mounted on a fixed position (fixed). Runners shall be placed in waterways or so-called 'casing', such that the incoming water will flow through the channels as parallel to the turbine so the turbine type of turbine is referred to as axial.Kaplan Turbine, named after the creator's name is V. Kaplan turbine is a turbine expert from Germany. Kaplan turbine propeller to the development by making the blade or turbine runner can be tuned even in operating conditions. Changing the blade angle is done using governor system thus improving the efficiency of the turbine's performance. Kaplan turbines are suitable for the geography that gives high falls between 3.0 meters to 30 meters and operates on a round of 60 to 220 rpm and can provide efficiencies up to 92%. 

Examples of calculating the Kaplan turbine rotation.Known data of a Kaplan turbine as follows: 

Power          : 50,000 bhp
Head            : 20 meters 
Efficiency    : 90% 
d/D              : 1/3 
Flow ratio   : 0.5 
Speed ​​ratio : 2 

Will be calculated diameter of the boss, and round duct diameter turbine as follows: 
i) The speed of water flow on the casing (channel), 
   V = 0.5 * (2 * g * H) ^ 0.5 
       = 0.5 * (2 * 9.81 * 20) ^ 0.5 = 9.9 m / sec. 

ii) The speed of water flow at the runner, 
  U = 2 * (2 * g * h) ^ 0.5 
      = 2 * (2 * 9.81 * 20) ^ 0.5 
      = 39.6 m / sec.

 iii) Debit of water through the channel: 
  E = BHP / WHPBHP = 50.000WHP 
      = (100 * Q * H) / 75E 
      = 50.000 * 75 / (100 * Q * H)Q 
      = (500 * 75) / (20 * 0.9) 
      = 195 m3/det. 

   For Q = 0785 (D ^ 2-d ^ 2) * V => 195 
     = 0785 * (3d ^ 2 - d ^ 2) * 9.9 => d 
     = 1.77 meters. 

   For d / D = 1 / 3 then D = 3 * 1.77 
    = 5.31 meters 

iv) U = (3.14 * D * N) / 60 => N 
   = (N * 60) / (3.14 * D) 
   = (39.6 * 60) / 3.14 * 5.31) 
   = 142 rpm