Pompa durmasıyla oluşan kararsız akımların deneysel ve teorik olarak araştırılması

Bu çalışmada pompanın duraklaması ile oluşan kararsız akımları teorik ve deneysel olarak araştırılmıştır Basınçlar pompa çıkışında ölçülmüştür. Vana ve dirsek kayıpları değişik debiler için ölçülerek yerel kayıp katsayılarının değerleri doğrudan elde edilmiş ve bu katsayılar için hıza bağlı olarak değişen ampirik bağıntılar türetilmiştir. Teorik sonuçlar, Karakteristikler Yöntemi kullanılarak ve Fortran dilinde yazılmış bilgisayar programı ile elde edilmiştir. Sayısal çözümde memba sınır şartını oluşturan pompanın davranışı boyutsuz parametreler kullanılarak yazılmış yük denge ve hız değişimi denklemleriyle ifade edilmiştir. Deneysel sonuçların teorik sonuçlarla uyumlu olduğu görülmüş olup gözlenen farklılıkların ihmal edilebilir mertebede olması kullanılan yöntem ve yaklaşımların uygun olduğunu göstermektedir.

Theoretical and experimental study of transient flows due to pump shut - off

The aim of this study is to search the unsteady flows due to shut-off of the pump. Pressures have been measured at the immediate outlet of the pump. Valve and elbow head losses were determined for different steady state discharges. Thus, the numerical values and empirical expressions for loss coefficients versus velocities were derived. Numerical results were obtained by computer program written in Fortran language using the method of characteristics. In numerical solution, the pump behavior which constitutes the upstream boundary condition is expressed by means of head balance and speed change equations written in terms of dimensionless parameters. An acceptable agreement is observed between theoretical and experimental results. Since the discrepancy between theoretical and experimental results is negligible, one can deduce that the used method and approaches are convenient.

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