Tekil ve Çoklu Yatay Su Alma Yapısı Bulunan Hidroelektrik Santrallerde Girdap Oluşumu ve Önlenmesi için Gerekli Düzeneklerin Belirlenmesi

TÜBİTAK MAG Proje01.10.2015İçme/sulama suyu temini veya elektrik enerjisi üretmek amacıyla yapılan su alma yapılarında,rezervuardaki su kotunun belli bir değerin altına düşmesi durumunda su yüzeyinde girdaplaroluşur. Girdaplar, sistemden geçecek olan debinin azalmasına, ilave enerji kayıplarına,pompa ve türbin verimliliklerinin düşmesine neden olabilecek havanın aralıklı veya sürekliolarak su alma yapısı içine çekilmesine neden olurlar.Bu çalışmada, farklı çapta yatay su alma sistemlerinde girdapların hangi su kotlarındaoluştukları ve rezervuar yan duvarlarının girdap oluşmasına etkileri deneysel olarakincelenmiştir. Bu çalışma TÜBİTAK tarafından desteklenmiştirThe aim of this study is to investigate the formation of air-entraining vortices at horizontalintakes, which is composed of a reservoir-pipe system, under assymetrical and symmetricalflow conditions. For this purpose two models, one with a single intake and one with multipleintakes, in METU Civil Engineering Department Hydromechanics Laboratory are used. Thefirst set of experiments are conducted on the single intake model for six different pipediameters. The seconds set of experiments are conducted on the multiple intake model whichhas three intake pipes with the same diameter. Different scenarios are tested here where onlya single intake is in operation or mutiple intakes are operating at the same time. In theseexperiments critical submergence depth is determined at which the air entraining vortices areformed. Adjustable sidewalls around the intakes are used in order to provide symmetrical orassymetrical approach flow conditions. Applying dimensional analysis a non-dimensionalfunctional relationship is obtained for critical submergence depth. Empirical relationships areobtained for critical submergence depth using regression analysis, where obtained equationsare compared with the similar expressions from the literature. Scale effect on the criticalsubmergence depth is investigated and it is found that neglecting some flow parameterscasuses a considerable change in this depth. Fixed plates and floating rafts at various sizesare tested as anti-vortex devices to elliminate formation of air entraining vortices and it isobserved that they are very successful in elliminating these