Case Study•Introduction - Project objectives - History - Field data
 •Analysis method - Computational Fluid Dynamics (CFD) - Visualization test
 •Project results
 •Lessons learne

Al-Ali, Saad

Al-Qahtani, Abdulaziz

Al-Shuhail, Yousuf

Bastiaansen, Tim

van den Berg, Nico

Texas A&amp;M Repository

Resolving cavitation problems of high energy water injection pumps Nico van den Berg Tim Bastiaansen Yousuf S. Al-Shuhail Saad A. Al-Ali Abdulaziz N. Al-Qahtani © Copyright 2014, Saudi Aramco and Flowserve. All rights reserved. Authors (1/2) Resolving cavitation problems of high energy water injection pumps 2 Yousuf Al-Shuhail  • Engineering Specialist with Saudi Aramco.   • 25 years of experience in rotating equipment.   • Worked in operations engineering for 16 years and currently working with central engineering providing consulting services to Saudi Aramco operating plants and projects and works in the development of Saudi Aramco standards.  Saad Al-Ali  • Senior Maintenance and Reliability Engineer working at the reliability unit head at Ras Tanura Producing Department in Saudi Aramco.   • Currently on special assignment with Abu Ali Maintenance Section in the same department.    • Bachelor degree in Mechanical Engineering from KSU with an honor degree.   • Joined Saudi Aramco late in 1997 and assumed different roles and responsibilities in his career and attended two successful commissioning and startup of big projects in Saudi Aramco facilities.   • Has excellent experience in plant maintenance and sound engineering sense.     Authors (2/2) Resolving cavitation problems of high energy water injection pumps 3 Abdulaziz Al-Qahtani • Rotating Equipment Engineer with Saudi Aramco. • 7 years experience in turbo machinery maintenance, troubleshooting, operation and selection in Aramco Northern Area Oil Operation Plants.   Nico van den Berg MSc • Hydraulic Engineer in the Central Project Engineering team with Flowserve. • 3 years experience in rotating equipment engineering. • Masters degree in Aerospace Engineering (specialization Aerodynamics) from Delft University of Technology.  Tim Bastiaansen MSc • Hydraulic Engineer in the Central Project Engineering team with Flowserve. • 3 years experience in rotating equipment engineering. • Masters degree in Mechanical Engineering (specialization Process Technology) from Eindhoven University of Technology.     Contents Resolving cavitation problems of high energy water injection pumps 4 • Introduction  - Project objectives  - History  - Field data  • Analysis method  - Computational Fluid Dynamics (CFD)  - Visualization test  • Project results  • Lessons learned Introduction – Project objectives Resolving cavitation problems of high energy water injection pumps 5 Design a new first stage impeller using CFD that will minimize cavitation and verify this with a visualization test. Introduction – Pump info Resolving cavitation problems of high energy water injection pumps 6 2005:  Commissioning of high speed Water Injection Pumps (WIP) at Saudi Aramco QATIF GOSP-2.  • Three identical pumps • Five stages • Single suction • Between bearing • Radial split barrel  (API 610 BB5) • Top-top nozzles • High speed (5000 [RPM]) • Fluid: raw water; TDS 11000 ppm  Introduction – Pump info Resolving cavitation problems of high energy water injection pumps 7 Introduction – Pump info Resolving cavitation problems of high energy water injection pumps 8 Design Operating range Flow 1104 820 1000 [m3/h] Head 1966 2303 2060 [m] Temperature 74 79 79 [°C] Power 8203 6711 7084 [kW] Speed 4964 4964 4964 [RPM] Ueye 54.5 54.5 54.5 [m/s] NPSHa 98.8 106.7 121.9 [m] NPSH3% 33.5 15.2 22.7 [m] NPSH40000 [h]  45.7 - - [m] Introduction – Field data Resolving cavitation problems of high energy water injection pumps 9 Introduction – History Resolving cavitation problems of high energy water injection pumps 10 2003 (FAT): Vane leading edge reworked to meet NPSH3%.  2008 (28000 [h] operation): 316 Stainless steel impeller (cavitation) damaged.  Upgrade to Nitronic 50. Introduction – History Resolving cavitation problems of high energy water injection pumps 11 2012 (13000 [h] operation): Nitronic 50 - impeller faces same damage pattern Required to re-design first stage impeller Analysis method – CFD Resolving cavitation problems of high energy water injection pumps 12 CFD simulations performed to determine NPSHi characteristic of:   • Original impeller  • Optimized impeller (new design) Analysis method – CFD Resolving cavitation problems of high energy water injection pumps 13 Principle: Shape the blade leading edge airfoil-style in order to have minimum pressure drop at the leading edge. This is referred to as a biased wedge leading edge design. Analysis method – CFD Resolving cavitation problems of high energy water injection pumps 14 New design: • Based on same parent impeller hydraulic as original • Five design iterations performed on NPSHi simulations • Design decisions: - Best Cavitation Point (BCP) near rated flow - 3% head drop criteria met at maximum operating flow  • By rapid prototyping, a full scale physical model was created Analysis method – CFD Resolving cavitation problems of high energy water injection pumps 15 Results: Analysis method – Visualization test Resolving cavitation problems of high energy water injection pumps 16 Analysis method – Visualization test Resolving cavitation problems of high energy water injection pumps 17 Analysis method – Visualization test Resolving cavitation problems of high energy water injection pumps 18 CFD: p < pvapor test: 1 mm bubble Analysis method – Visualization test Results @ rated flow and NPSHa Resolving cavitation problems of high energy water injection pumps 19 Original New Project results Resolving cavitation problems of high energy water injection pumps 20 • Impeller leading edge has been optimized using CFD and the improvement has been verified with a visualization test  • Biased wedge design decreased the cavity lengths significantly:   No cavitation at 100% and 80% of rated flow @ NPSHa  40.000 hours lifetime will be met   Lessons learned Resolving cavitation problems of high energy water injection pumps 21 • A biased wedge design can improve cavitation characteristics significantly for a wide range of flow rates  • The 3% head drop is an inappropriate criterion for high energy pumps having high eye peripheral speed  Lessons learned: revised standard Resolving cavitation problems of high energy water injection pumps 22 Pump type NPSH3% curve 40000 [h] curve  Visualization test Acceptance criteria All pumps Margin  MCSF[1]-120 %  > 1 [m] High energy  water injection pumps Depth of penetration < 75% of vane thickness Water injection pumps eye peripheral velocity > 47 [m/s]  Depth of penetration < 75% of vane thickness [1] Minimum Continuous Stable Flow Required  Not required Resolving cavitation problems of high energy water injection pumps 23 Thank you for your attention.  Questions? 

Resolving Cavitation Problems of High Energy Water Injection Pumps

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Resolving Cavitation Problems of High Energy Water Injection Pumps

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Resolving Cavitation Problems of High Energy Water Injection Pumps

Abstract

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Texas A&amp;M Repository

Texas A&M Repository