Experimental Investigation of Unsteady Flow in a Vertical Shaft Axial Flow Pump

Öz

Due to the changes in the system characteristics, pumps may have to be operated far away from the design point, such as in part-load or over-load operating points. Operating the pumps far away from the design point may cause fluctuations in the flow. As a result of the fluctuations mechanical problems in the pump structure may occur. In order to overcome the problem, the operating characteristics of the pump must be determined at part load operating conditions as well as design point operating condition. In this study, flow inside a vertical shaft axial flow pump is investigated experimentally. The experimental setup is designed and constructed for the laboratory tests. The pump which is designed and manufactured is tested in the test setup. The performance of the pump is determined by measuring the flow rate, inlet and outlet pressures, rotational speed and power input of the pump. The part load and over load operating regions are determined. Pressure variations are measured at various performance points with the piezoelectric pressure transducer placed in between impeller and diffuser blade passage. Simultaneously, comparisons are made with the vibration spectrums obtained in the pump. 

Anahtar Kelimeler

• Vertical shaft axial flow pump
• piezoelectric pressure transducer
• part-load flow
• recirculation
• flow-induced vibration

Düşey Milli Eksenel Bir Pompada Zamana Bağlı Akışın Deneysel Olarak İncelenmesi

Öz

Sistem karakteristiğindeki değişimler nedeniyle pompalar tasarım noktalarının dışında, kısmi yükte veya aşırı yükte çalıştırılma durumunda olabilirler. Pompaların tasarım noktasının dışında özellikle önerilmeyen bölgelerde çalıştırılması birçok akış problemlerine sebep olmaktadır. Bunun sonucu olarak mekanik problemler meydana gelmektedir. Bu problemin üstesinden gelmek için pompanın tasarım noktasındaki karakteristiği yanı sıra kısmı yükteki çalışma koşullarının belirlenmesi gerekmektedir. Bu çalışmada, düşey milli eksenel bir pompanın içerisindeki akış deneysel olarak incelenmiştir. Laboratuvar testleri için deney düzeneği tasarımı yapılarak imal edilmiştir. Tasarımı ve imali yapılan pompa bu deney düzeneğinde test edilmiştir. Pompa performansını belirlemek için, debi ölçümü, pompa giriş-çıkış basınçları, pompa dönme hızı ve güç ölçümü yapılmıştır. Kısmı yük ve aşırı yük bölgeleri tespit edilmiştir. Çark ile difüzör arasına yerleştirilen piezoelektrik basınç algılayıcısı kullanılarak basınç değişimleri ölçülmüştür. Eş zamanlı olarak pompada elde edilen titreşim spektrumları ile karşılaştırmalar yapılmıştır.

Anahtar Kelimeler

• Düşey milli eksenel pompa
• piezoelektrik basınç algılayıcısı
• kısmi yük
• döngüsel akış
• akışkan kaynaklı titreşim

Kaynakça

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