Steam and Gas for Power Generation

Nowadays, gas and steam turbines are contributing to more than 80% of the electricity generated worldwide. If we add the contribution from hydro turbines too, then we reach 98% of total production.

The improvement of the flow path is crucial, and an advanced design can be achieved through several strategies. The aerodynamic optimization of gas and steam turbines can lead to enhanced efficiency. In addition to that, the minimization of secondary losses is possible by introducing advanced endwall shaping and clearance control. Moreover, further increase of efficiency can be achieved by decreasing the losses of kinetic energy at the outlet from the last stage of the turbine. This can be done using longer last-stage blades as well as improving the diffuser recovery and stability.

Flow Path
Flow Path of a Gas Turbine

Moreover, increased gas turbine performance is very much related to an increase of the turbine inlet temperature. However, the coolant mass flows will need to be minimized at the same time to achieve the highest performance benefits possible [1]. Therefore, effort must be put on the development of advanced cooling system concepts for the engine’s first stage components. New cooling surfaces as well as new cooling schemes should be studied by CFD modelling to use the coolant in the best possible way before it leaves the component.

A phenomenon that must be further addressed in this context is hot gas ingestion which can cause unacceptably high rotor temperatures. We need to develop more advanced technologies that will handle hot gas ingestion to make sure that the hot gases will be confined in the cavity without reaching the rotor itself. To use new sophisticated cooling methods based on porous structures a new method of thinking is necessary. Analysis methods, design concepts, and criteria must be developed and tested for such structures in order to optimize the design for components with porous structures. High temperature materials in gas turbines have properties that change significantly during the expected life of the component due to thermal exposure, mechanical load and the combination of the two. Issues that affect lifting and reliability and can cause serious problems are, for example, crack propagation usually due to creep or fatigue. In many components, early TBC (Thermal Barrier Coating) spallation will increase the material temperature of the component and reduce the safe life for which the component can be used [1].

Considerations for any power system, new or existing, include not only efficiency and optimization, but also cost, longer life-cycle of components, and keeping pace with current environmental restrictions. Given the scale of some of these projects, accurate early-stage design is critical for project success, whether it’s a new construction or retrofit.

At SoftInWay we have built our reputation on creating accurate preliminary design models for such projects. Our strength in engineering and power plant consulting combined with our AxCYCLE® heat balance calculation software are core offerings of success for turbomachinery design in the power generation sector.

References:

[1]http://www.euturbines.eu/cms/upload/publictaions/documents/EUTurbines_Roadmap_on_Turbomachinery_Research-final.pdf

 

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