Browsing by Author "Kumar, Arun"

Now showing 1 - 20 of 20
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    Anatomy of an Extreme Event
    (American Meteorological Society, 2013-04-26) Hoerling, Martin; Kumar, Arun; Dole, Randall; Nielsen-Gammon, John; Eischeid, Jon; Perlwitz, Judith; Quan, Xiao-Wei; Zhang, Tao; Pegion, Philip; Chen, Mingyue
    The record-setting 2011 Texas drought/heat wave is examined to identify physical processes, underlying causes, and predictability. October 2010–September 2011 was Texas’s driest 12-month period on record. While the summer 2011 heat wave magnitude (2.9°C above the 1981–2010 mean) was larger than the previous record, events of similar or larger magnitude appear in preindustrial control runs of climate models. The principal factor contributing to the heat wave magnitude was a severe rainfall deficit during antecedent and concurrent seasons related to anomalous sea surface temperatures (SSTs) that included a La Niña event. Virtually all the precipitation deficits appear to be due to natural variability. About 0.6°C warming relative to the 1981–2010 mean is estimated to be attributable to human-induced climate change, with warming observed mainly in the past decade. Quantitative attribution of the overall human-induced contribution since preindustrial times is complicated by the lack of a detected century-scale temperature trend over Texas. Multiple factors altered the probability of climate extremes over Texas in 2011. Observed SST conditions increased the frequency of severe rainfall deficit events from 9% to 34% relative to 1981–2010, while anthropogenic forcing did not appreciably alter their frequency. Human-induced climate change increased the probability of a new temperature record from 3% during the 1981–2010 reference period to 6% in 2011, while the 2011 SSTs increased the probability from 4% to 23%. Forecasts initialized in May 2011 demonstrate predictive skill in anticipating much of the SST-enhanced risk for an extreme summer drought/heat wave over Texas.
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    Centrifugal Compressors: Operation and Maintenance, Advanced Design, Wet and Sour Gas Operation
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Baumann, Urs; Baldassarre, Leonardo; Gupta, Manoj; Hataya, Takeshi; Konomi, Shin; Kumar, Arun
    Topics Outline: • Meeting current rotordynamics stability standards • High flow coefficient/mach number impellers • Low flow coefficiens/high pressure impellers; Reynolds correction Complicated high pressure gas properties. E.g., CO2, acid gas, H2S • Testing of the equipment • Modern manufacturing/forming methodologies • Simulation and dynamic process modeling • Handling of Chlorides in sour/acid gas applications, including piping; end-user strategies Hermetically-sealed compression
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    Centrifugal Pump Operation, Maintenance, and Reliability
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) DePaolis, David; Donley, Richard; Gottlieb, Adam; Stevenson, Calvin; Pairemore, Paul; Krauel, Nick; Kumar, Arun; Strautman, Katie; International Pump Users Symposium (33rd : 2017)
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    Centrifugal Pump Operation, Maintenance, and Reliability
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) DePaolis, David; Donley, Richard; Gottlieb, Adam; Stevenson, Calvin; Pairmore, Paul; Kumar, Arun; Whaley, Katie; Heggemann, Marc; International Pump Users Symposium (34th : 2018)
    Repair Specs, use, in house repair specs Lube oil storage and usage Mechanical seals and bearings issues Pump monitoring how are we doing this and how do we want to do this Craft training precision maintenance Best practices for pump maintenance; Back pullout vs. pulling entire pump: Open bearing housings vs sealed wet sump Seal plan which was not expected wrong for the application Preventive/predictive technologies Off design operation Mean time between failure (MTBF), other KPIs how do we measure, and how do we use the metrics How to create pump reliability in an unreliable plant Seal-less versus sealed pump reliability, canned motor pumps versus mag drive pump reliability Mechanical Integrity Inspections of VS 6 pumps in hydrocarbon service Seals in light hydrocarbon service operations, risk, leak response, maintenance Pump predictive/preventive maintenance program elements philosophy, frequencies. Measures of effectiveness of preventive and predictive programs for pumps Roles of operations and maintenance/reliability in improvements and data collection Reliability experience with liquid versus non contacting gas seals applications Maintenance philosophy for pumps what constitutes best practices Spare parts OEM versus non-OEM Repairs OEM versus non-OEM service facilities Pump foundation, alignment and pipe strain influence of reliability Impact of corporate purchasing alliances on pump reliability a. Repair facilities alliances b. New equipment purchasing alliances Repair techniques and material improvements Portable and on-line monitoring impact on reliability Wireless monitoring impact on reliability and risk of failure Optimization of thrust bearings configuration
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    Compressor Dry Gas Seal Failure Due To Oil Ingress
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Kumar, Arun; Brar, Navneet Singh; Turbomachinery Symposium (47th : 2018)
    This case study of a typical tandem arrangement dry gas seal failure during compressor start-up elaborates importance of start-up environment consideration during design for a compressor dry gas seal system. The seal failed due to oil ingress during compressor start-up. The case study presentation details out following major contents: * Chronological events leading to dry gas seal failure, relevant data * Findings/observations during subsequent maintenance * Root cause analysis and outcomes * Corrective actions & subsequent performance * Key learning
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    Discussion Group T15: Steam Turbine Design, Operation, and Maintenance
    (Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Patel, Vinod; Stevenson, Stanley; Bhat, Gampa; Fisher, Rob; Kumar, Arun; Moreno, Joe; Turbomachinery Symposium (45th : 2016)
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    Discussion Group T17: Steam Turbine Design, Operation, and Maintenance
    (Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2015) Patel, Vinod; Stevenson, Stanley; Bhat, Gampa; Fisher, Rob; Kumar, Arun; Turbomachinery Symposium (44th : 2015)
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    Do You Have a Mechanical Seal Refurbishing Shop in Your Complex?
    (Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Sabharwal, Mohit; Kumar, Arun; Paliwal, Dilip
    Case Study 24: Author intends to convey: 1. Importance of having Mechanical Seal Refurbishment facility in a refinery complex, supported by interesting case studies on critical mechanical seal failures. Minimum set up required for In-house Mechanical Seal Refurbishment facility. 2. The success story of having a Mechanical Seal Refurbishment facility at 9MMTPA Grass Root Refinery, which proved a major factor in timely project completion and vital during the safe and successful refinery commissioning and steady state operations. 3. At what stage the Mechanical Seal Refurbishment facility should be functional in the project?
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    High Vibration Problem Resolution in Centrifugal Pump through Design Change
    (Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Shet, Mahesh; Kumar, Arun; Singh, Navneet
    Case Study 4: The case study is about single stage API BB2 pump. Pump operates at the temperature of 355 degree C (671 degree F), rated for pumping 442 m3/hr of Hydro-treated VGO (Vacuum Gas Oil) and is driven by a steam turbine. Pump bearing housing at Drive End (DE) side started exhibiting intermittent high vibrations during commissioning phase. This resulted in repeated failure of DE bearing and damage to bearing housing. Root cause was analyzed as uneven expansion of pump casing during pump warm-up, which misaligns the DE side floating bearing within bearing housing and restrict its axial displacement (bearing used is of deep groove design). As a consequence, thermal growth of pump shaft was restricted and it was rotating in deflected shape, rubbing within throat bushes. Problem was resolved by replacing the bearing design with NU type Cylindrical roller bearing, which allows higher amount of axial displacement. This case highlights a balanced approach towards the site investigations, root cause analysis and corrective actions implementation. It also provides hints to address thermal growths issues when equipment operates at very high temperature.
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    High Vibrations & Component Failure In Turbomachinery Due to Magnetic Currents
    (Texas A&M University. Turbomachinery Laboratories, 2006) Kumar, Arun; Turbomachinery Symposium (35th : 2006)
    Objective: To share with users of Turbomachinery the fact that High Speed Turbomachinery with components possessing Residual Magnetism produces high shaft voltages & high current, which can lead to severe problem like high Vibrations, damage to the machine components and can cause heavy production loss. Scope: The Case Study details this typical problem due to residual magnetism in Synthesis Gas Compressor at National Fertilizers Limited, Panipat Unit, INDIA, in which the problem lead to repeated overhaulings of compressor, replacement of three numbers of rotors, damage to number of bearings & Oil film seal rings . It details work associated in diagnosis of the problem, measure taken for temporary relief, so as keep machine running and final work done for permanent solution of the problem. Result of the Case Study: The machine behaved normally after the rectification job, at low vibration levels. Lesson Learnt : The Residual Magnetism can cause typical problems in Turbo machines, like High Vibrations, Component Failure, causing severe limitations in machine. Its early detection is typical but ways are there to detect it. The users of Turbomachinery & the Maintenance Team have to take precautions so as to prevent introduction of Residual Magnetism in the machine.
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    High Vibrations & Component Failure in Turbomachinery due to Magnetic Currents : Its Detection, Diagnosis & Correction
    (Texas A&M University. Turbomachinery Laboratories, 2007) Kumar, Arun; Turbomachinery Symposium (36th : 2007)
    Objective: To share with users of Turbomachinery the fact that High Speed Turbomachinery with components possessing Residual Magnetism can produce high shaft voltages & high current, which can lead to severe problem like high Vibrations, damage to the machine components. Scope: The Case Study details problem & diagnosis of the problem due to residual magnetism in Synthesis Gas Compressor at National Fertilizers Limited, Panipat Unit, INDIA. The problem lead to repeated overhaulings of compressor, replacement of three numbers of rotors, damage to number of bearings & Oil film seal rings.
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    P05 - Centrifugal Pump Operation, Maintenance, and Reliability
    (Turbomachinery Laboratory, [2019]) Kumar, Arun; Donley, Richard; Whaley, Katie; DePaolis, David; Stevenson, Calvin; Pairmore, Paul; Gottlieb, Adam; Putnam, Thomas
    Top Voted for Discussion in 2017: MI Inspections of pumps - (casing thickness) UT, on-line, shops; Methods for preventing reverse rotation, detecting reverse rotation; Hot alignment is there benefits, what temperature; Predictive maintenance how is info recorded, also condition based how it is working; What oil are we using for lubrication bearing housings (oil type, replacement frequencies); Motor greasing and use of UT; Pump swapping program - Frequency; Pump monitoring how are we doing this and how do we want to do this, wireless, Craft training precision maintenance : Additional Possible Discussion Topics: Pump maintenance practices pull all pump vs just back pullout assy.; Vertical Canned Pumps (VS6 Pumps); Parallel pumping practices, pump switchover; Practices for Mothballed Pumps; Repair Specs, use, in house repair specs; Lube oil storage and usage; Mechanical seals and bearings issues; Best practices for pump maintenance; Back pullout vs. pulling entire pump: Open bearing housings vs sealed wet sump; Seal plan which was not expected wrong for the application; Preventive/predictive technologies; Off design operation; Mean time between failure (MTBF), other KPIs how do we measure, and how do we use the metrics; How to create pump reliability in an unreliable plant, etc. . .
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    Save Your Centrifugal Machinery During Commissioning
    (Texas A&M University. Turbomachinery Laboratories, 2014) Kumar, Arun; Sabharwal, Mohit; Turbomachinery Symposium (43rd : 2014)
    During the commissioning of centrifugal machines (Compressors, steam turbines, pumps, fans etc.), a lack of flushing, inspection and ignorance of critical areas & procedures can lead to major problems, damage, and serious safety issues. These serious issues and damages lead to a delay in startup of the refinery, resulting in large monetary loss & further delay as major spares required to carry repairs may not be available in initial stage. It is possible to prevent such damage by following the procedures and inspections which are discussed in detail in this paper. The tutorial covers the experience and learning derived by the commissioning of more than 5,000 rotating machinery equipment over the past 5 years. The Tutorial will illustrate what can go wrong with centrifugal machinery during commissioning and startup and actual case studies of damage are provided along with the corrective and preventive measures suggested for successful commissioning. A Checklist of Do’s and Don’ts to be followed before and during commissioning is also provided.
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    Save your Centrifugal Machinery during Commissioning
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Kumar, Arun; Sabharwal, Mohit
    During the commissioning of centrifugal machines (Compressors, steam turbines, pumps, fans etc.), a lack of flushing, inspection and ignorance of critical areas & procedures can lead to major problems, damage, and serious safety issues. These serious issues and damages lead to a delay in startup of the refinery, resulting in large monetary loss & further delay as major spares required to carry repairs may not be available in initial stage. It is possible to prevent such damage by following the procedures and inspections which are discussed in detail in this paper. The tutorial covers the experience and learning derived by the commissioning of more than 5,000 rotating machinery equipment over the past 5 years. The Tutorial will illustrate what can go wrong with centrifugal machinery during commissioning and startup and actual case studies of damage are provided along with the corrective and preventive measures suggested for successful commissioning. A Checklist of Do’s and Don’ts to be followed before and during commissioning is also provided.
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    Severe Corrosion On Rotor Blades of Back Pressure Type Steam Turbine Due to Unique Reason. What Went Wrong?
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Kumar, Arun; Chopra, Anurag; Turbomachinery Symposium (46th : 2017)
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    Steam Turbine Design, Operation, and Maintenance
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Patel, Vinod; Stevenson, Stanley; DiOrio, Gerry; Bhat, Gampa; Kumar, Arun; Moreno, Joe; Turbomachinery Symposium (46th : 2017)
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    Steam Turbine Design, Operation, and Maintenance
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Patel, Vinod; DiOrio, Gerry; Bhat, Gampa; Kumar, Arun; Moreno, Joe; Turbomachinery Symposium (47th : 2018)
    Overhaul intervals Maintenance practices Solid particle erosion Contract versus in-house maintenance Mechanical driver turbine issues - design et al Steam path repairs Turbine casing and alignment issues Steam turbine performance, degradation, etc. Reliability/availability
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    Steam Turbines: Operation & Maintenance
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Josefczyk , Ronald; Kumar, Arun
    Suggested Topics: • Overhaul intervals • Maintenance practices Solid particle erosion • Contract versus in-house maintenance Mechanical driver turbine issues - design et al • Steam path repairs • Turbine casing and alignment issues • Steam turbine performance, degradation, etc. • Reliability/availability
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    T15 - Steam Turbine Design, Operation, and Maintenance�
    (Turbomachinery Laboratory, [2019]) Patel, Vinod; Cole, Alan; Bhat, Gampa; Kumar, Arun; Moreno, Joe; Barrington, Brian
    Overhaul intervals Maintenance practices Solid particle erosion Contract versus in-house maintenance Mechanical driver turbine issues - design et al Steam path repairs Turbine casing and alignment issues Steam turbine performance, degradation, etc. Reliability/availability