Revamping a Turbomachine Train

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.

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Figure 1 – Flow Chart

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

4 thoughts on “Revamping a Turbomachine Train

  1. What do you mean by: ” by redesigning the flow-relevant components”…? And which ” calculation tool is usually available for each process step” are you referring to? OEM produced? Supplier/seller produced?

    1. Hi George,
      by redesigning the flow-relevant components means to modify or to replace components like: blades, vanes, or channel contour of the machine. The calculation tools are mostly the in-house tools, MISES for modifying the machine, or Dyrobes or MADYN. It is very time consuming to connect all these tools to each other through their ASCII output data. An Integrated Development Environment (IDE) for turbomachinery like AxSTREAM, offers an agile development process. Moreover. the IDE offers with its open interfaces for scanned custom geometry (AxSLICE) the turbo service provider a full capability to model an existing machine without any manufacturing drawings.
      Trust this will answer your questions.

      1. Erwin, thank you for your response but the main issues I had in mind were not addressed: if you modify the hot section parts like blades and vanes, you have likely altered the turbine thermodynamics, thus possibly affecting output, fuel consumption, cooling, etc. You will also need to readjust the controls settings. Firstly, this must be a tough sell to the owner. Secondly, who will assume responsibility in the event of power loss, premature parts failure or other possible negative consequences from the re-design and new controls settings?

        1. George,
          I’m fully agree with you that the service provider must also sell the changes of controls and auxiliaries. In my humbly opinion, this shall not be tough. As long as the safety base concept of the train will not be changed. Changes will only apply e. g. on Alarm or Trip values as well as on dimension size of valves or other safety relevant apparatus. This strategy will avoid unnecessary work to perform new SEAL-Analysis within the significant change of the train safety concept. The revamped train can preserve its existing safety certificate and it can be declared as inventory protection, since the safety concept has been proven over the years of operating.

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