Turbomachinery is a core subject in many engineering curriculums. However, many graduates joining the oil and gas industry are designated as rotating equipment engineers. Though turbomachinery and rotating equipment are used synonymously, all turbomachinery are rotating equipment but not vice versa. Turbinis in Latin implies spin or whirl, and a natural question that arises is – what are the factors that differentiate turbomachinery? In a general sense the term, “rotating” covers the majority equipment used in the industry be it in the upstream, mid-stream or the downstream segment. Yet top rotating equipment specialist in the industry are seen spending their prime time or often being associated with certain unique and specific types of critical rotating machines – the turbomachines.
In a classical sense, turbomachines are devices in which energy is added into or taken out from a continuously ﬂowing ﬂuid by the dynamic action of one or more moving blade rows. By this definition propellers, wind turbines and unshrouded fans are also turbomachines but they require a separate treatment. The subject of ﬂuid mechanics, aerodynamics, thermodynamics and material mechanics of turbomachinery when limited to machines enclosed by a closely ﬁtting casing or shroud through which a measurable quantity of ﬂuid passing in unit time makes the practical linkage to rotating equipment – those which absorb power to increase the ﬂuid pressure or head (fans, compressors and pumps) and those that produce power by expanding ﬂuid to a lower pressure or head (hydraulic, steam and gas turbines). Further classification into axial, radial and mixed type (based on flow contour), and impulse & reaction (based on principle of energy transfer) is common. It is the large range of service requirement that leads to different type of pump (or compressor) and turbine in service.
From the oil and gas industry perspective, standards namely API governs the specifications of design, material and systems requirements of rotating equipment. In line with such standards, equipment under the purview of APIs SOME (Sub Committee on Mechanical Equipment) are considered to quantify rotating machine. Falling under the turbomachinery group are centrifugal pumps (API 610), general and special purpose steam turbines (API 611 & 612), gas turbines (API 616) , axial and centrifugal compressors and expander- compressors (API 617), special purpose fans (API 673) and integrally geared compressors (API 672).
It is understandable that universities and academic institutions will continue their focus on turbomachinery as a fundamental subject of the curriculum, with increased emphasis on training and use of CAE tools. Basics remaining the same, the special nature of application of turbomachinery in the industry makes job of a rotating equipment engineer a challenge. At a conceptual level four important facets of rotating equipment (turbomachines) that an engineer in the oil and gas industry need to comprehend are as follows: Kinematic, energetics and thermodynamics of performance– fluid-aero thermal design and analysis; integrity of rotor, bearings, seals, casing and structure – mechanical design and analysis; the complete hardware – metallurgy, material mechanics and manufacturing and finally the associated systems. As the oil and gas industry entrusts its specialist rotating equipment engineers with a demanding level of reliability and availability of turbomachines, new ways are required to enhance competence. The practical experience of rotating equipment engineers coupled with exposure to design principles and use of CAE and simulation tools is one such way to help them add more value to their business. AxSTREAM® is an advanced software suite that covers many aspects of various critical rotating equipment for the oil and gas industry on a single platform.
The demands of the plant construction and energy sector after a shorter response time for questions upon newly defined operating points of a turbomachine train are one of the biggest challenges in the service business. This becomes particularly obvious if the future points can only be realized by redesigning the flow-relevant components. Often, it is necessary to have more time to check the dynamic behavior of the train, than in the development of the appropriate revamp measures for the core machine itself.
In addition to the different utilization rates of the affected departments, the causes of the delays often lie in the lack of interface quality between the design/ calculation and train integration team. On top of that, a certain amount of time will be required by manufacturers of the critical components such as gearboxes or drives to perform a lateral check. This lateral check is not only mandatory, in case of a component modification such as changing the transmission ratio or upgrading the drive, but it is also necessary if the coupling between the train components must be changed to ensure torsional stability.
The flow chart to the right shows the general process flow from revamping a turbomachine train. On the line to the left of the figure, the revamp’s main processes are shown. The process flow starts with the revamp of the core machine and ends with the fulfillment of the feasibility criterion in the torsional analysis. A calculation tool is usually available for each process step. It results from in-house development, university’s research or from a commercial manufacturer. Overall, in a process flow as per above, several tools which come from different manufacturers are used.
Normally, each tool outputs its result in a text file whose content conforms to the ASCII standard and is unstructured. The fact that the output file is unstructured, makes it clear, an update or a completion of the tool means an enormous effort for the company which is responsible for the train integration. It must examine the individual interfaces and adapt them as necessary. Furthermore, it must also carry out the immensely important work of the benchmarking of the overall result.
Implementing a text file with a hierarchical data structure as output is one of the simplest solution approaches to fix the interface problem. However, because most of the tools historically have been written in the obsolete programming language, writing the results in a hierarchical data structure is very difficult to achieve. Another approach is the application of an integrated development environment for turbomachinery. Because all tools come from a single manufacturer, the interface quality is now guaranteed. To apply the core competencies of the machine manufacturer, the environment should be able to integrate the specific characteristics of flow-relevant components such as loss and leakage models into the calculation.
Check out SoftInWay’s integrated platform AxSTREAM for flow path design and redesign
When deciding on a new product line, manufacturers of turbomachines and their engineering teams must often decide whether to rescale a product that they already manufacture or to begin a full design process for a completely new machine. For example, a producer of 5 MW axial turbines wants to start manufacturing 10 MW turbines, does it make sense to create a brand new design from scratch or to simply scale up the 5 MW turbine they already produce to a similar 10 MW version? To answer this question, many considerations have to be taken into account, the general answer however is, that it is almost always a better idea to start a new design.
Improved Design Technology
Many manufacturers wrongly believe that by simply scaling their current product that they will save not only on design costs, but that they can leverage their existing manufacturing capabilities to stamp out a similar product. What is not factored in however is the progress of design technology and theory since their original machine was first conceptualized. The result from a simple scaling process will simply be a less optimized and efficient machine for any use as compared to a new configuration using the latest in design software. Increasing software sophistication and computing power are constantly pushing the boundaries of efficiency while minimizing operating costs. Simply put, your competitors will have designed a superior product compared to yours.
AxSTREAM 3D Blade Design Software
When was your current machine designed? Many older machines were created using materials that by today’s standards are simply not capable of operating at the extreme conditions (mostly temperatures) required today to attain the energy efficiency requirements set up by ever increasing regulations. Depending on materials used, the optimal blading structure, bearings, etc. geometries would be significantly unique. If one were to simply scale up their current product, they would either be using old materials or have inefficiently designed machine components for a different material. In either case, their scaled machine will be inferior to a configuration that was conceptualized and optimized from scratch.
Another very significant aspect of machine resizing is that it is not a straight forward process; if you want to double your power generation in a turbine for example you are not going to be doubling the blade size or mean diameter, for example, even when considering the same boundary conditions (inlet pressure and temperature, as well as, outlet pressure, rotation speed, and so on). For each specific set of conditions, fluid, rotation speed, mass flow rate, etc. a unique flow occurs inside the different blades. Changing one parameter will lead to changes in the flow and therefore result in inefficiencies, as it is what happens in off-design conditions (the machine is not operating at its maximum performance). This is why flow similarity parameters become relevant.
Machine Purpose and Type
One of the obvious questions to ask is, what is the purpose of my new machine and how much larger (or smaller) will I need it to be? If the new machine is intended for use with a completely different fluid, a new design will be optimal as different fluids interact in unique ways with varied rotor and stator configurations.
The machine type that you are considering is also critical to the decision. Different turbomachines do not scale in similar fashion with increase in size. For instance, radial turbines are usually not as efficient as axial turbines when one starts to approach the 2 MW range. In this instance the ideal solution is for a complete redesign since a smaller scale version that the manufacturer may have had would not be configured to operate at higher power ranges efficiently.
I hope everyone is having a great week. I wanted to write about our education system, as it relates to Turbomachinery, and perhaps some challenges that educators / students face, and some ideas for how things can be improved.
As computation technologies have evolved over the last 30-40 years, it seems that a large number of education institutions are still behind.
Part of my job at SoftInWay, is to make sure that local & global Universities involved in Turbomachinery have the most advanced software tools, so that the students graduating from undergraduate, as well as Masters and PhD level programs, have some kind of relevant skills to develop / optimize Turbomachinery, as well as know how to use relevant software tools.
From talking to Academia from different countries, it seems that professors (perhaps due to bureaucracy of their positions) are often faced with several challenges / decisions:
1. No budget for software tools thus forced to use free tools
2. Desire to create their own software, to eventually spin off and start a company
3. Lack of deep technical program, thus only picking macro topics as they relate to turbomachinery as general thermodynamics, etc. (which is important also).
What’s the problem with all of these approaches: When students graduate, and want to go into the field of Turbomachinery, a large portion of these students think that “Turbomachinery Design” can be done with CFD.
Looking at the last 5-10 years of CFD as it relates to Turbomachinery, people have been in several “camps”, with the most known names (such as products from Ansys, or CD Adapco (now owned by Siemens), Numeca, and some free open source CFD codes. Additionally, there has been a plethora of free or academic codes written by 100s of wide-eyed graduates students in hoping of making the next big software company.
Why does this cripple the education system, industry and the general concept of innovation? First of all, in all of these packages, you are going on the assumption that you already have a geometry of the turbomachinery and generally know what the machine looks like. Granted, some advertise that by “partnering” with other vendors they can do 1D or inverse design, when looking at these options closely, they are still very weak. At the same time, there are lessor known CFD packages (from example our Turbomachinery specific CFD module AxCFD that we offer) that while hasn’t been aggressively marketed, comes at 30% of the cost, and has not only faster computation speed, but is fully integrated in a complete turbomachinery design platform. While this is a great option for students, very few know about it, and we are always stuck with a thought “people need to understand the complete process of design, not just CFD, so let’s focus on teaching that, and sharing that message”.
In addition to working with Universities, another part of my job at SoftInWay is hiring, so what have i learned from looking at 1000s of resumes from masters and PhD students?
If you start to dig deeply, about what candidates have learned about turbomachinery design, how well do they understand, for example, compressor aerodynamics, or gas turbine cooling, quite often the answers come up short. This creates a steep learning curve, not just for our company, but also for major manufacturers and service providers.
We believe, that instead of the next generation of students, trying to re-invent the wheel, and spend their 2,3,4,5,6 years of education on equations and writing code, for a problem that has been solved, they should use a holistic approach, to advance, Power Generation, Transportation, Propulsion and Advance the clean energy space.
We have created a range of free resources for students in an online university format (learn.softinway.com) and encourage everyone to dig deeply, and together we can create a greener world, for the future generations.
Additionally, our turbomachinery development platform AxSTREAM (r), is the only platform in the world which is wholly integrated and developed in-house, including thermodynamic cycle design, 1D,2D,3D turbomachinery design, analysis and optimization, rotor dynamics and bearing design, stress analysis, advanced optimization and visualization, etc.
** Feel free to fact check this by looking at your current software simulation tools, and see how many modules or features or “tools” are borrowed from other companies. How can one ever learn and understand how things work and talk to each other, if knowledge is not developed, but rather borrowed.
If you are a student, or a professor at a college or university, and are interested in improving your turbomachinery program, and giving your students the extra skills (fundamentals and software), to really develop innovations, please write me a message !
Innovation Strategy: How to Leverage Turbomachinery Reverse Engineering
SoftInWay will be hosting its next free webinar on Thursday, November 12! This webinar will delve into the complicated world of reverse engineering and demonstrate the best methods and tools.
Reverse engineering of Turbomachinery is extremely important for the partial replacement of turbines or compressors that have operated for many years, especially for owners, operators, and non-OEM service providers.
Documentation for a significant amount of these machines is not available due to different reasons, thus replication/reproduction becomes costly and time consuming. In the owner/operator scenario, one of the options is to buy new, modern machinery (as a replacement), but this is often significantly more expensive than performing overhauls & optimization of the flowpath, while maintaining the casing and other components. For OEMs looking to study a competitor’s machine, things become even more complicated.
SoftInWay’s turbomachinery software platform, AxSTREAM, has a unique capabilities for extracting turbomachinery geometry and profiles from scanned data, thus streamlining the reverse engineering, benchmarking, duplication, and optimization process. Additionally, by leveraging the extensive experience of SoftInWay’s 60+ person engineering team, customers are able to benefit from our techniques and software for different types of overhaul, rerates, cycle changes, and other sophisticated projects.
The webinar will include:
- An introduction to the reverse engineering of turbomachinery including its origins and modern trends
- The significance of special software and specialized experience for reverse engineering of turbomachinery
- Information on how to leverage reverse engineering and modern software to improve existing turbomachinery performance
- Examples of reverse engineering-based improvement, innovation, and modification
Who should attend:
- Engineering professionals performing or involved in reverse engineering projects
- Engineering professionals working in the mechanical, aerospace, automotive, marine, or power generation industries seeking to renovate or improve existing turbomachinery equipment
- Engineering professionals working in turbomachinery operation who want to renovate or improve their equipment performance
- Engineering students looking for comprehensive and state-of-the-art approaches for turbomachinery reverse engineering
Register for this webinar by clicking the link below! Can’t attend? Register and we will make sure you receive a recording of the presentation.
Our next webinar will be held on February 26th and cover the best industry practices when it comes to power plant redesign. The constant increase of global energy consumption and rising cost of fuel require higher energy generating capacity with a simultaneous improvement of the efficiency of energy conversion processes. The greatest effect of improving the performance of existing power plants and other energy systems can be obtained by modifying the thermodynamic cycles of these plants.