Turbomachinery Problems And Solutions

[Shanta Plansinis]

TheTurbo Lab and MFPT along with the Hydraulic Institute and the Vibration Institute have formed a cooperative effort to expand the scope of presentations at the annual MFPT conference. Turbo Lab will present Vibration Problems and Solutions in Turbomachinery and Centrifugal Pumps, a full-day course offered on May 13 in conjunction with the MFPT 2019 conference, May 14-16 in King of Prussia, Pa. at the Crowne Plaza Hotel.

The course covers intermediate and advanced techniques for measuring, interpreting, and mediating vibration in turbomachinery and centrifugal pumps. The new method of motion-amplified video is explained and demonstrated. Modern troubleshooting methods and fixes are provided, with many case histories.

Course instructor William (Bill) D. Marscher is a ten-year veteran of the pump advisory committee for the Turbomachinery & Pump Symposia, hosted by the Turbo Lab annually in Houston. Marscher is president and technical director of Mechanical Solutions, Inc., where he and other staff perform design, analysis, testing and troubleshooting of pumps and miscellaneous turbomachinery. Bill has more than 40 years of hands-on and design experience with rotating machinery. Maki M. Onari, vice president of engineering for Mechanical Solutions, Inc., will teach alongside Marscher. Onari has extensive experience in resolving rotating machinery problems. His expertise includes field testing and associated capabilities in instrumentation, data acquisition and analysis equipment, and analysis of vibration and other dynamic machinery data.

The Texas A&M Engineering Experiment Station (TEES) Turbomachinery Laboratory makes a vital impact on turbomachinery and related industries through research, education and professional workforce development.

Vibration, excessive noise, failures, and other dynamics-related problems that limit or prevent operation are often experienced in gas turbines. Unexpected problems may be experienced shortly after installation, after a major repair, or as a result of premature failure. Engineers at Southwest Research Institute (SwRI) are trained and equipped to respond quickly and comprehensively to unscheduled gas turbine outages or performance limitation problems.

Contact us for more information about our troubleshooting turbomachinery operating and installation capabilities. To contract with SwRI, please contact the Machinery Services Hotline at +1 210 522 3000.

Concepts NREC's engineering consulting services can supplement and support your in-house capabilities with world-class technology, specialized methods, and proven experience in fluid mechanics, heat transfer, combustion, applied mechanics, production, and system controls. Our engineers work closely with you to understand and resolve various performance, structural, and rotordynamic problems in individual machines, entire turbomachinery trains, or complete plant systems.

Concepts NREC helps you solve difficult engineering problems to improve the efficiency, performance, and manufacturability of your compressors, pumps, turbines, fans, blowers, and turbochargers. We can work from existing specifications or only a statement of the desired requirements.

An APS subscription is included with all annual licenses and is a highly-recommended option for perpetual software licenses. Every software customer is supported for one month following purchase for any installation questions that may arise. Learn more on the Agile Products Support Membership Benefits Datasheet.

Our integrated design and manufacturing software tools provide designers with a cost-effective, concurrent development approach that balances issues of performance, reliability, cost-effectiveness, and manufacturability.

It's true that this development has been great for Conhagen, which has seen accelerated hiring alongside the growth of business. But this push has also been a calculated effort - one several years in the making.

Conhagen is happy to announce the creation of the Mechanical Engineering, Design and Systems group, or MEDS. The MEDS group is a dedicated engineering team, aimed at tackling tough applications and providing technical support where traditional design techniques or standard equipment is found unfit for reliable operation. As the department has seen continued growth, the skillset of the team has gone from hydraulic and mechanical design expertise to vibration analysis and rotordynamics, precision metrology, reverse engineering and root cause failure analyses - not only in centrifugal pumps, but high-energy steam turbines and compressors.

As advances in engineering tools are made, Conhagen has always been ready to adapt, learn and implement solutions to old and new problems. Recently, Conhagen began using Axstream, a best-in-class solution for the design of turbomachinery in axial and radial machines. Our engineers can develop in-house tools for most problems, but there is value in recognizing when better tools exist, and when to use them.

Conhagen has always believed in a customer-centric, hybrid model that breaks down organizational silos and pairs engineers, salespeople and shop repair coordinators in a way that any and all inquiries and follow-ups are given a direct line to the right person. Salespersons are no strangers to customer interaction, as our sales force has always emphatically engaged our customer base. However, as jobs near completion, often times there are technical or scheduling questions that should be addressed to specific persons within the Conhagen organization. Our size and agility allow us to route the lines quickly and efficiently. Additionally, our doors are always open to customers, and they are encouraged to visit and ask questions as they perform root cause analysis or equipment assessments.

One of the signature philosophies that Conhagen has developed in the 80 years since the inception of the company is that the customer truly owns the equipment, the designs and all of the pertinent information that accompanies its proper function and troubleshooting. At the completion of a job, the engineering reports, calculations, manufacturing drawings, assembly drawings, models and inspection reports are all submitted to the customer for their records.

We believe that true added value comes in the form of customer independence which is created when they are given a full disclosure of the work done from start to finish. Of course, Conhagen is always ready and willing to assist customers, but we believe this transparency relieves bottlenecks in the information pipeline between when equipment is pulled and when it gets reinstalled.

Conhagen has committed to the creation of a dedicated turbine and compressor repair shop, located at their La Marque, Texas facility. The shop will be run in conjunction with the main repair shop, which will continue to primarily work on centrifugal pumps. With our size, we will be able to share skills and personnel laterally to accommodate different locales. In other words, all three shops, Texas, Louisiana and California will have the same capabilities from a pump, compressor and turbine repair standpoint.

At the start of 2022, Conhagen was joined by mechanical engineer, Andrew Mills, formerly of Ethos Energy and Turbocare. Mill's vast experience and knowledge of steam turbines and compressors have breathed new life into the repair capabilities and engineering expertise offered by Conhagen.

As an ideal source of numerous practice problems with detailed solutions, the book will be helpful to senior-undergraduate and graduate students, teaching faculty, and researchers engaged in many branches of fluid mechanics. It will also help practicing thermal and fluid design engineers maintain and reinforce their problem-solving skills, including primary validation of their physics-based design tools.

Rui Fernandes, General Manager, Shaft Current Solutions (dba Sohre Turbomachinery), discusses the problems created by shaft current and electrical discharges, as well as how to resolve them.[/caption]

Shaft Current Solutions (dba Sohre Turbomachinery) manufactures equipment and provides consulting services, relating to the protection of rotating equipment from electrical discharges. They sell grounding brushes, design shaft grounding/earthing systems, and help diagnose the cause of shaft current problems.

The most common problem is pitting and deterioration of the interface surfaces between components such as bearings, journals, seals, and gears. Depending on the intensity of the electrical discharges, the damage can be gradual, slowly eroding bearing surfaces and requiring the replacement/refurbishment of components during scheduled services; or it can cause extensive damage and force the machine offline in just a few hours of operation.

Depending on the source of the electrical discharge, ignoring the issue can lead to reduced component life and unscheduled outages. In some cases, magnetized components can produce high enough current levels to force machines offline. There were some extreme cases in which the levels of magnetism were intensified by the current generated (known as self-excitation), which led to rapid and catastrophic machine failure.

There are three primary approaches to address the problem: eliminate the source of the electrical current, change the properties of lubricating fluids to eliminate charge accumulation, or dissipate excess electric charges to ground (earth) using sliding contacts. The elimination of electrical sources is ideal, and we work with our customers to do so whenever this is feasible, as is the case with magnetized components. In our experience, that is the most dangerous source of electrical currents. However, the generation of electrical charges is inherent in the flow of fluids and those we cannot fully eliminate. There have been several attempts at changing the conductivity of lubricating fluids to prevent the accumulation of charges. However, our anecdotal experience is that this seems to change the discharge voltage threshold rather than eliminate electrical discharges. Lastly, the approach that is used by us and others, is the use of sliding contacts to dissipate accumulated charges.

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