Several attempts pursued by a plant and their supplier, over the years, did not find the root cause of a shaft cracking problem, in spite of the good troubleshooting procedures and careful installation practices pursued. Therefore, an exceptionally comprehensive root cause investigation was implemented, with specialty vibration testing at its core.
The U.S. electrical power generation market is quite complex, and currently in a significant state of change. Baseload coal plants are closing, and natural gas, with a highly variable fuel cost, is the prescribed replacement. New nuclear construction is currently plagued by the familiar bugbears of schedule and cost overruns, making investment in additional plants uncertain.
This paper demonstrates accurate cavitation modeling using advanced CFD tools with comparison to experimental data for reference.
Engineers have been making use of the Interference Diagram as a tool for assessing potential for impeller structural resonance for decades now. It is also referred to in the literature…
Detecting the cause of machinery vibration can sometimes prove elusive. If you have had your switchgear fail due to exciter bolt tension, or have ever sought to diagnose high vibration levels that have appeared with no apparent cause, or come and go in seemingly random intervals, or have always exceeded their twin machine that is “the same,” you may have encountered resonance.
This tutorial focuses on vibration issues in pumps primarily for power plants, refineries, and municipal water and waste water treatment plants. When vibration is due to a resonance of a structural natural frequency or an unexpected geometry change such as looseness or cracking, solutions become more complicated. This tutorial will provide an in-depth look at how the combination of field testing and computer analysis can solve vibration issues is a timely and cost-effective manner.
Mechanical Solutions, Inc. (MSI) was contracted to perform several CFD analyses of an axial hydroturbine, with the purpose of validating the experimental data obtained by a hydroturbine test loop. MSI employed two CFD codes, ANSYS CFX and STAR-CCM+, which were used to conduct several transient analyses, three of which are detailed in this paper. The results of the transient analyses revealed good correlation between the numerical predictions and the experimental data.
MSI was an early adopter of remote troubleshooting technology. In this article, MSI describes troubleshooting a steam turbine vibration problem in Asia from the other side of the globe in our headquarters in New Jersey. Details about the problem, troubleshooting method, and engineered solution are described.
Aeroderivative gas turbines are used to drive LNG compressors. This article describes a problem solving process used to address a turbine problem that was introduced as part of a coupling retrofit. The specialized testing and analysis techniques are applicable to compressors, as well as other system components (heat exchangers, fractionation towers, etc.) used in LNG facilities…
As new commercial applications arise for supercritical CO₂ (sCO₂) power generation, and higher output and efficiencies are achieved through higher turbine inlet pressures and temperatures, the need to improve component technologies becomes essential. Traditionally lubricated and cooled oil bearings cannot tolerate the higher temperatures, and the higher pressures make keeping the oil separate from the working fluid an increasingly difficult challenge.
This classic Sound & Vibration article explains the basis for when and how to use of an interference diagram in assessing the potential for resonance problems in a centrifugal impeller or axial-bladed disk.
This Sound and Vibration article explains the benefit of modal evaluation while the machine is running, and provides a real world example of how MSI does it. An electric power generating plant located in the Northeastern U.S. had suffered through chronic boiler feed pump failures for eight years due to modulated-load operation. Rather than replacing the rotor element with a new, custom design, MSI got to the bottom of the real problem.
Avoid installing preventable vibration problems by utilizing modern Finite Element Analysis (FEA) techniques. The following pump system design assessment methodology is applicable for new plant construction or for plant modifications such as upgrading to more efficient motors or installing Variable Frequency Drives (VFD).
This case study examines the powerful integrated capabilities between the turbomachinery design tool CFturbo and the computational fluid dynamics analysis tool STAR-CCM+ to produce an automated design of experiments, achieving optimized performance for a hydroturbine.
This presentation, given at the 26th International Pump Users Symposium in 2010, describes how MSI used Operating Deflection Shape (ODS) Characterization to solve a vibration issue with a Ring-Section Pump. Using advanced troubleshooting techniques, MSI was able to recommend modifications to the baseplate that greatly reduced the vibration level.
Learn how to use accelerometers and dynamic pressure transducers in the time domain to investigate cavitation root causes, and to quantify the cavitation severity. The technique presented allows for a minimally invasive test of the pump system.
Maki Onari presented a real-world case study of troubleshooting a Reactor Feed Water Pump. This presentation was given at the 45th Turbomachinery & 32nd Pump Symposia (2016) in Houston, TX.
In this Turbomachinery International article, MSI demonstrates how to utilize field testing data to calibrate a Finite Element Analysis (FEA) model to first replicate then problem, then establish a solution without resorting to trial-and-error problem solving.
Understand the context and power of using high-speed video for vibration analysis and machinery diagnostics.
In this Institute of Physics Journal of Physics article, the authors compare analytical computational fluid dynamics (CFD) results to experimental results. Numerical predictions of the Francis-99 hydroturbine using the commercial CFD code STAR-CCM+ correlate well with experiment. Net head, discharge, runner torque and hydraulic efficiency all correlate closely with experimentally observed values. Nearly all quantities are predicted within 3.5% of the experimental observation.
This tutorial outlines the basics of pump rotordynamics in a form that is intended to be Machinery End-User friendly. Pump rotordynamic problems, including the bearing and seal failure problems that they may cause, are responsible for a significant amount of the maintenance budget and lost-opportunity cost at many refineries and electric utilities.
Turbines need to run at very high temperatures to reduce fuel burn, but they require internal cooling to maintain structural integrity and meet service-life requirements. Engineers used simulation to evaluate state-of-the-art turbine-blade cooling-channel geometries and developed an innovative geometry that outperforms existing designs.
Interested in accurately predicting unstable modes in pumps using unsteady, multiphase computational fluid dynamics (CFD)? This a great article by MSI’s Edward Bennett and Artem Ivashchenko on the power of…
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