Page - 1379 - in Book of Full Papers - Symposium Hydro Engineering

Surface Roughness of the ramp When constructing the ramp, attention must be paid to minimizing surface roughness along a sufficient length and gradation. An approach to the calculation of the energy equation for run off on the ramp, taking account of losses due to roughness, is as follows: HA=HE [2] HA,0+Z(x)=HE0+hv [3] HA,0+Z(x)= hE+ vE 2 2∙g + vm 2∙ΔX KST 2∙Rh 4 3⁄ = Q vE∙b + vE 2 2 ∙g + vm 2∙ΔX KST 2∙Rh 4 3⁄ [4] Optimal conditions (for example kSt = Strickler values) are to be specified in this development project. Table 1 List of different materials and roughness values are as follows Material Strickler-factor 𝒌 𝑺 𝒕 in 𝒎 𝟏 𝟑 ⁄ 𝒔 ⁄ sheet steel 100 skimmed concrete 85 preformed concrete 80 wood 75 rough concrete 50 As can be demonstrated when considering the design of the ramp of an ejector power plant, the main criterion is the reduction of the roughness to a minimum (for example by utilizing sheet steel plate). Fig. 21 Water flow speed at the end of the ejector ramp in relation to the roughness [3] 1379