Influence of the Reshaped Elbow on the Unsteady Pressure Field in a Simplified Geometry of the Draft Tube

Raul-Alexandru Szakal, Alexandru Doman and Sebastian Muntean
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Raul-Alexandru Szakal: Faculty of Mechanical Engineering, University Politehnica Timisoara, Blvd. Mihai Viteazu, No. 1, 300222 Timisoara, Romania
Alexandru Doman: Faculty of Mechanical Engineering, University Politehnica Timisoara, Blvd. Mihai Viteazu, No. 1, 300222 Timisoara, Romania
Sebastian Muntean: Faculty of Mechanical Engineering, University Politehnica Timisoara, Blvd. Mihai Viteazu, No. 1, 300222 Timisoara, Romania

Energies, 2021, vol. 14, issue 5, 1-21

Abstract: The paper focuses on the influence of the reshaped elbow geometry of the draft tube on the unsteady pressure field under different operating conditions. The experimental investigations are conducted considering two simplified geometrical configurations of the draft tubes with sharp heel elbow and modified/reshaped elbow, respectively. The discriminated power spectra (rotating and plunging components) of the acquired pressure signals on the wall are determined on five levels for seven operating conditions to quantify the influence of the reshaped elbow. The influence of the reshaped elbow on the fundamental frequencies of both rotating and plunging components and on the amplitude of the rotating component is negligible. In contrast, the equivalent amplitude associated with the root mean square of the plunging power spectrum that propagates along the hydraulic passage is mitigated up to 25% by the reshaped geometry of the elbow. The equivalent amplitude on the narrow band around the fundamental frequency of the plunging component is diminished with 40–50% by reshaping the elbow geometry of the simplified draft tube.

Keywords: unsteady hydrodynamics; draft tube; simplified geometry; variable conditions; reshaped elbow (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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