Effect of Dimensions and Mesh Type of Anti-Vortex Horizontal Plates on Critical Submergence Reduction of Vertical Intakes

Vertical intakes are common structures to supply water through reservoirs or conveying channels for agricultural, urban and industrial zone’s demand. Of course, this method has its problems and some difficulties such as vortex flow formation at inlet and air entrance are observed, which cause rather problems, e.g. reduction of intake capacity and motivation of vibrations and cavitation initiation. In this research the effects of dimensions and mesh type of the horizontal stationary plates on critical submergence of vertical intakes were studied experimentally. First, some tests were carried out to determine discharge-critical submergence relation for a condition with no anti-vortex device establishment. Then, a dimensionless equation was fitted between relative submergence and intake Froude number. Finally, the effect of each plate with a specified dimension and mesh type were examined at a constant situation for five different flow rates. The performance of plates in reducing critical submergence was calculated for each setup. Based on the results, the SP 2d plate had the best performance of 46.2%. Also, a regression equation was fitted to predict relative submergence in the presence of anti-vortex plates, using dimensionless parameters of Froude number, relative plate dimensions and relative mesh area.