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Rainwater propeller pumps structural integrity

Sergiu Valentin Galatanu (Mecanică şi Rezistenţa Materialelor, Universitatea Politehnica Timişoara, Timişoara, România)
Sebastian Muntean (Centrul de Cercetări pentru Ingineria Sistemelor cu Fluide Complexe, Universitatea Politehnica Timişoara, Timişoara, România) (Centrul de Cercetări Tehnice Fundamentale şi Avansate, Academia Română Filiala Timişoara, Timişoara, România)
Liviu Marsavina (Mecanică şi Rezistenţa Materialelor, Universitatea Politehnica Timişoara, Timişoara, România)
Iulian Ionut Ailinei (Mecanică şi Rezistenţa Materialelor, Universitatea Politehnica Timişoara, Timişoara, România)
Dan Micota (Mecanică şi Rezistenţa Materialelor, Universitatea Politehnica Timişoara, Timişoara, România)

International Journal of Structural Integrity

ISSN: 1757-9864

Article publication date: 26 June 2019

Abstract

Purpose

The purpose of this paper is to focus on the structural integrity of the rainwater propeller pumps installed in the municipal wastewater treatment plant (WTP).

Design/methodology/approach

A numerical analysis is performed to determine the maximum shear stress on the fasten bolts. The rainwater propeller pump is examined in operation at normal conditions and when one blade is progressively blocked.

Findings

The failure mechanism of the rainwater pump impeller is determined.

Research limitations/implications

The fibbers and wastes are discharged together with rainwater during storms with these types of pumps to avoid the flood of the WTP. Several catastrophic events have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The clogging process is partially understood so actual technical solutions deal with effects rather the main causes.

Practical implications

The operation time of all seven rainwater pumps installed in Timisoara’s WTP is investigated. Climate changes in Banat region and new waste properties found in the wastewater require appropriate technical solutions. A technical solution is proposed based on these investigations to extend the operation time and to diminish the operation and maintenance costs.

Social implications

These large pumps are installed in the urban sewage centralised system implemented in the most cities. The access to the sewerage network is a requirement of any community, regardless of the social status.

Originality/value

The fracture surfaces of both fastening bolts of the rainwater pump impellers produced in service are examined. As a result, it has been identified that the catastrophic events are due to the brittle fracture of both fasten bolts between the impeller blades and the pump hub, respectively. The catastrophic events of the rainwater propeller pumps are directly correlated to the clog level of the impeller. The numerical simulation is performed to determine the maximum shear stress on the fasten bolts. The case with pump operating at normal conditions is performed identifying its vulnerabilities to clog conditions. Next, one impeller blade is progressively blocked considering three time stop scenarios associated with different clog levels. Conclusively, the operating time of the rainwater pump up to the catastrophic failure is correlated to the clog level of the impeller.

Keywords

Acknowledgements

The authors are grateful for the financial support of Bridge Grant TANAGRA/63BG2016 project code PN-III-P2-2.1-BG-2016-0082 financed by the Romanian Government and supported by Municipal Water and Wastewater Company AQUATIM SA Timişoara. The authors would like to thank Dr Ilie Vlaicu, General Manager and Dr Ionel Aurel Draghici, Project Manager at AQUATIM SA Timişoara for their valuable support.

Citation

Galatanu, S.V., Muntean, S., Marsavina, L., Ailinei, I.I. and Micota, D. (2019), "Rainwater propeller pumps structural integrity", International Journal of Structural Integrity, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/IJSI-10-2018-0070

Publisher

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Emerald Publishing Limited

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