Steam Turbine Stage Modernisation in Front of the Extraction Point

The paper presents modernisation of the steam turbine stage situated in front of the turbine extraction point, based on a 225 MW turbine LP stage as an example. The modernised design is intended to better control the steam flow in this area. In the presented design a special ring is used to drive the steam leakage flow directly to the heat exchanger. The performed experiments and numerical analyses confirmed measurable exploitation and efficiency advantages of the introduced modernisation. So far, it has been successfully applied in a number of turbines working in inland power plants, but its use can be easily extended, without need for further modification and without advantage loss, to marine turbines, especially those used as main propulsion in sea-going vessels.

Effects of Steam Ingestion on Under Fuselage Inlet Performance During a Catapult-Assisted Takeoff Process

A naval aircraft has the potential to experience inlet performance decline when taking off from the carrier deck with the steam-driven catapult assistance. The steam ingested into inlet may cause time-dependent rise and spatial distortion of the total temperature on the inlet–exit, which would decrease the compressor stall margin and then lower the performance of the turbine engine. In this paper, these temporal and spatial temperature nonuniformities are numerically studied using the dual-time-step transient method with a real aircraft/inlet model taken into account. The flowfield characteristics of a designed baseline case are first analyzed, indicating that the engine’s suction effect and the wind velocity relative to the aircraft are two key factors affecting the steam ingestion. The former is dominant at the beginning of takeoff since the aircraft's velocity is low, while the latter is increasingly significant as the aircraft accelerates. Next, parametric studies show that the greater the wind speed is, the less significantly the flowfield of the inlet–exit would be influenced by the steam. The effects are also studied among various steam leakage profiles—two are constant in time histories of the steam leakage rate, whereas the other two are nonlinear with the maximum value at different instants. It is found that the temperature rise rate of the inlet–exit would increase apparently if the steam leakage rate reaches the maximum earlier.

A method of diagnosing labyrinth seals in fluid-flow machines

A method of diagnosing labyrinth seals in fluid-flow machines Steam turbines constitute fluid flow machines which are used for driving engines of power plants, merchant and naval ships. They are commonly applied in power industry to driving electric generators. One of the impotant elements which affect efficiency of steam turbines used in power industry and for ship propulsion is state of labyrinth sealings whose aim is to minimize losses associated with steam leakage within turbine casing. Until now to assess state of labyrinth sealings has been only possible after stopping the turbine and its dismantling in order to determine values of clearances in the sealings. This paper presents a method which makes it possible to assess state of labyrinth sealings without the necessity of stopping and dismantling the machine. This is the method which allows to assess on-line state of machine sealings during its operation.