Civil Engineering, Khaje Nasir Toosi University of Technology
Power stations with high heads are nowadays almost without exception designed so as to have one pipeline, or a few pipelines, supplying the water to the turbines. The penstocks are connected to a distributor, which has the task of distributing the flow with the lowest possible losses of energy to the individual turbines. The function and location of this section of the plant make it understandable that its safety is regarded as a matter of outstanding importance. Careful selection of materials, followed by continuous and extremely meticulous inspections of work-pieces and production processes enable the manufacturer to rule out unwarrantable risks as regards materials. Furthermore, well-substantiated method of computation and experimental stress investigations make it possible to control stresses occurring in the complicated bifurcations. Thus adequate safety and economical design of the construction are ensured by suitable matching of stress levels to the properties of the materials used. The experimental work included over the two of three types of different sickle rib geometries on non-symmetric wye-branch upon certain critical flow conditions are presented. The objectives of the studies were to determine the influence of the geometry and size of sickle rib on head losses in Karun I conical wyes. The prototype of wye consists of six conical at the main and three extended cylindrical, one for inflow and two for out flow. The scale of model is 1:25 which three types of sickle ribs can be assembled on the model.