High Specific Speed In Circulating Water Pump Can Cause Cavitation, Noise And Vibration

Autor: Chandra Gupt Porwal
Jazyk: angličtina
Rok vydání: 2015
Předmět:
DOI: 10.5281/zenodo.1110883
Popis: Excessive vibration means increased wear, increased repair efforts, bad product selection & quality and high energy consumption. This may be sometimes experienced by cavitation or suction/discharge recirculation which could occur only when net positive suction head available NPSHA drops below the net positive suction head required NPSHR. Cavitation can cause axial surging, if it is excessive, will damage mechanical seals, bearings, possibly other pump components frequently, and shorten the life of the impeller. Efforts have been made to explain Suction Energy (SE), Specific Speed (Ns), Suction Specific Speed (Nss), NPSHA, NPSHR & their significance, possible reasons of cavitation /internal recirculation, its diagnostics and remedial measures to arrest and prevent cavitation in this paper. A case study is presented by the author highlighting that the root cause of unwanted noise and vibration is due to cavitation, caused by high specific speeds or inadequate net- positive suction head available which results in damages to material surfaces of impeller & suction bells and degradation of machine performance, its capacity and efficiency too. Author strongly recommends revisiting the technical specifications of CW pumps to provide sufficient NPSH margin ratios >1.5, for future projects and Nss be limited to 8500 - 9000 for cavitation free operation.
{"references":["\"Investigation of Recirculation Effects on the Formation of Vapour\nBubbles in Centrifugal Pump Blades\" by Mohammad Taghi Shervani\nTabar, Seyyed Hojjat Majidi, Zahra Poursharifi, -World Academy of\nScience, Engineering & Technology- 49 2011.","\"Pump Cavitation-Various NPSHR Criteria, NPSHA Margins And\nImpeller Life Expectancy\" by Bruno Schiavello, Director Fluid\nDynamics, Applied Technology Department Philipsburg, New Jersey\nand Frank C. Visser, Principal Design & Fluid Dynamics Engineer,\nFlowserve Pump Division, Technical Services, Central Engineering\nEtten-Leur,The, The Netherlands. Proceeding of the Twenty-Fifth\nInternational Pump Users Symposium-2009.","\"Detecting Cavitation in Centrifugal Pumps\" by Jeremy Jensen, Project\nEngineer and Kenwood Dayton, Sr. Research Engineer, Bently Rotor\nDynamics & Research Corporation, Orbit journal 2nd Quarter 2000, page\nno 26-27.","\"Hydraulic Institute standards\": Pump Operations, Efficiency, Testing &\nSystems and NPSH margin; www.pump.org/","\"Pump Cavitation and High Pressure Liquid Health Essay\" by\nUKEssays.com..","\"A review of Nss Limitations-New Opportunities\" by Michael\nHirschberger, Head of Hydrodynamic Department and Ian James\nEngineering Manager, Ruhrpumpen Inc. of Ruhrpumpen Group, Tulsa,\nOklahoma. Proceeding of The Twenty-Fifth International Pump Users\nSymposium-2009.","\"How to Avoid Expensive Pump Failures and Repairs from Cavitation\nby Determining the 'Suction Energy' of a pump\", WaterWorldCE.com.","\"Specific Speed v Suction Specific Speed\" Newsletter on pumps and\nreliability, Nov 2007 by Dale B. Andrews- Lawrence pumps\nhttp:/www.lawrencepumps.com","\"Specific Speed\" by Steve Wilson by Grundfos (White Paper)\nhttps://www.grundfos.com/\n[10] \"All About Specific Speed 7-3\" http://www.mcnallyinstitute.com\n[11] \"Does Impeller Affect NPSHR?\" by Daisude Konno, Senior Engineer\nand Project Team Leader and Yoshiyuki Yamada, Design Engineer,\nHydraulic Machinery Department Ebara Corporation Tokyo, Japan,\nProceedings of The First International Pump Symposium.\n[12] \"Understanding Pump and Suction Specific Speed\" by PDH online\nCourse M136 (2PDH) Randall W. Whitesides, PE 2012,\nPDHonline.com.\n[13] \"Sufficient NPSH Margin Important to Pump Reliability\" by Allan R.\nBudris, www.waterworld.com/\n[14] \"What is Best Efficiency Point?\" Frequently asked questions\nhttp://epumpdoctor.com/\n[15] \"Avoid Repeat Pump Failure\" By Heinz P. Bloch, P.E., Process\nMachinery Consulting, www.plantservices.com/\n[16] \"Article #3: Suction Specific Speed\" http://www.pump-magazine.com/\n[17] \"Centrifugal Pump: Which Suction Specific Speeds are Acceptable?\" by\nJ. L Hallam, Amoco Oil Co. Texas City, Texas. Hydrocarbon\nProcessing, April 1982, page 195.\n[18] \"Pump Vibrations\" by W.E(Ed) Nelson, Consultant Dickinson, Texas &\nJ. W. Dufour, Chief Engineer, Mechanical Equipment Services, Amoco,\nOil Company, Chicago, Illinois -Proceedings of The Ninth International\nPump Users Symposium,\n[19] \"Can Pump Design Upgrades Allow Lower Flow Operation without\nNPSHR Recirculation Damage?\" by Lev Nelik, Ph.D., June 2014 in\nPumps & Systems. www.pumpsandsystems.com/\n[20] \"Cavitation Prediction\" www.pumpfundamentals.com/ [21] \"Why NPSHR Changes With Impeller Diameter?\" by Petroskills by John\nM Campbell, www.jmcampbell.com/\n[22] \"Which is Which Cavitation or Recirculation?\" by John C. Robertson\nPE/CPE, AMSCO Inc. 105 Goldenrain Way, Simpsonville, S.C.\n29680, www.maintenanceresources.com/\n[23] \"What is Pump Cavitation?\" Crane Engineering, Optimizing Fluid\nSystem Performance. Posted by Brad Parkhurst. (July 10. 2014).\n[24] \"Influence of Impeller Suction Specific Speed on Vibration\nPerformance\" by David Cowan, Hydraulic Engineer, ITT Goulds Pumps\nBasingstoke, Hampshire, UK, Simon Bradshaw, Director of API Product\nDevelopment & Technology And Thomas Liebner, Hydraulics Engineer,\nITT Goulds Pumps, Seneca Falls, NY, USA. Proceedings of Twenty-\nNinth Turbomachinery International Pump Users Symposium, October\n1-3, 2013, Houston, Texas.\n[25] \"Understanding Pump Curves #6 Minimum Flow\" Part Two: Suction\nSpecific Speed by Ron Astall, United Pumps Australia. Courtesy PIA\nAustralian Pump Technical Handbook.\n[26] \"Pump Guy Mailbag: Minimum Acceptable Flow for Effective Pump\nOperation\" by Larry Bachus http://www.flowcontrolnetwork.com/pumpguy-\nmailbag-minimum-acceptable-flow-for-effective-pump-operation/\n[27] WPIL Limited India, Data sheet of CW Pumps (3x500 MW )"]}
Databáze: OpenAIRE
Externí odkaz: