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Advanced Pump Engineering for Severe Applications

Periodic Reporting for period 2 - APESA (Advanced Pump Engineering for Severe Applications)

Période du rapport: 2017-06-01 au 2019-05-31

APESA, Advanced Pump Engineering for Severe Applications, is a Marie Skłodowska-Curie Actions European Industrial Doctorate programme with beneficiaries Weir Minerals Netherlands (WMNL) and the University of Strathclyde (UofS), UK. WMNL design and manufacture large positive displacement diaphragm pumps for bulk transport of solid materials in slurry form in the global mining, minerals and energy industries. The pumps are designed for a 25 year working life, during which they experience continuous material damage due to the abrasive and corrosive nature of the slurry. Understanding how complex mechanisms involving corrosion, erosion and fatigue affect pump structural integrity and field-life is critical to safe and economic design. This is important to society in terms of environmental protection, energy cost, efficient use of materials, product competitiveness and global wealth generation.

The specific objectives of the APESA project were: to investigate material damage mechanisms; develop predictive behaviour models; and engineer mitigation strategies to limit material damage. The project was structured through five independent but inter-related projects, in which five Early Stage Researchers (ESR) were recruited and trained to form a collaborative multidisciplinary research cohort. Marta Morgantini researched the effect of induced tensile stress (due to bolt loads, etc.) on corrosion-fatigue life; Volodymyr Okorokov researched the effect of induced compressive stress (due to material strengthening processes such as autofrettage, etc.) on corrosion fatigue life; Francesco Rizzuto researched Computational Fluid Dynamics modelling of flow cavitation in pumps for design application; Blazej Polakiewicz researched failure modes in valve components and valve material selection; and Evripidis Tsergas researched electrochemical corrosion protection systems for pump applications.
Each ESR had two Academic Supervisors at UofS and an Industry Supervisor at WMNL, to ensure research training was delivered within the context of industry need and practice. In this way, the ESRs gained knowledge and experience ranging from lower TRL academic research through to higher TRL industry assessment, development and implementation. The Researchers registered for individual PhD study at UofS and complementary skills training was structured through a parallel Postgraduate Certificate in Researcher Professional Development.

The ESR research projects covered a wide range of scientific and engineering research activity, including: extensive material laboratory test programmes (fatigue, corrosion, corrosion fatigue, wear, corrosion protection); material characterisation and failure analysis; development and implementation of a new cyclic plasticity material model; Finite Element Analysis (FEA) of pre-load and fatigue test conditions, Computational Fluid Dynamics (CFD) of cavitation flow and Boundary Element Analysis (BEA) of Sacrificial Anode Corrosion Protection in pumps.

The combined outcomes from the projects of Marta and Volodymyr led to the proposal of a new, advanced methodology for stress-life prediction of corrosion fatigue life in the presence of residual stress (tensile and compressive), utilising the new fatigue data, cyclic plasticity FEA and critical distance representation of fatigue cracks. The proposed method was successfully validated through industry-scale corrosion-fatigue testing on the WMNL dynamic pump test rig. Francesco formulated and implemented a new 1D CFD system for compressible flow with cavitation of suitable complexity, accuracy and computational requirements for use in an engineering design environment. The model was validated against test results from the WMNL pump rig and field measurements taken at a mining industry pumping station in Brazil. Evripidis’s laboratory test data was used in BEA modelling of cathodic protection systems in an established GEHO pump design, proving the concept of the potential benefit of such systems in industry applications. Blazej’s investigation of materials and coating for valve applications considered new metal matrix composite materials, which were initially thought to be promising candidates for industry application but were later found to be less effective than other less expensive materials.

Overall, the APESA project has delivered valuable new knowledge and insight to WMNL in terms of understanding, quantifying, modelling and mitigating damage mechanism in slurry pumps, in line with the project objectives. Research outcomes have been disseminated to the wider science and engineering communities through ESR presentations at international conferences in Europe, the USA and Canada. Three papers are published/in-press in leading international research journals, another is currently in the review stage and others are currently in preparation. The ESRs engaged in public communication and dissemination of the APESA project through their conference, seminar and workshop activities and other public events, including the annual UofS Engage Week, MSCA Innovative Training Network events and International Women in Engineering Day. Further industry dissemination was achieved through ESR presentations during site visits and secondments to Weir Group companies and clients (Europe, USA, Brazil) and to the Weir Group Executive Technology Board.

WMNL have developed Implementation Strategies for exploitation of research findings and outcomes within the WMNL design environment. Design IP is anticipated upon completion of these programmes, with early transfer of outcomes from the corrosion fatigue and CFD projects expected. The new cyclic plasticity material model has been implemented in the WMNL FEA environment and the cavitation flow CFD system has been implemented in the WMNL CFD environment. The Implementation Strategy for the corrosion protection and valve materials projects identifies requirements for further research prior to WMNL adoption.
The APESA project has made significant progress beyond the state of the art in stress-life modelling of corrosion fatigue. This includes new material data for corrosion fatigue life under a range of environmental and loading conditions, disseminated in the public domain, and a new cyclic plasticity material model, reported in two journal papers, able to fully represent the effect of residual stress induced by material strengthening processes. For WMNL, the ability to accurately represent mean stress effects in bolted assemblies and autofrettaged components offers designers significant scope for design optimization. However. the proposed methodology is general and applicable in a wide range of industries in which corrosion fatigue is a problem, including oil and gas, power and biomedical devices. The plasticity material model also has potential application in general structural integrity assessment for shakedown and ratcheting analysis. The new CFD facility will give WMNL designers the capability to simulate and hence minimise cavitation in different pump arrangements in an industry-appropriate analysis environment, leading to reduced cavitation damage. Together, these new capabilities will result in lower initial pump cost and increased reliability, directly reducing the total cost of pump ownership. This will lead to increased WMNL product competitiveness and enhanced global wealth generation through pump applications in the mining, minerals and energy sectors.