Piotr Krzyślak

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.

Calculations of labyrinth seals with and without diagnostic extraction in fluid-flow machines

ABSTRACT Labyrinth seals are essential components of steam turbine unit constructions. Two types of labyrinth seals can be named, the first of which is the seal without diagnostic steam extraction, and the second - with extraction. The distribution of flow parameters along the packing is affected remarkably by the average seal clearance. The presence of diagnostic extraction leads to the equation system which is determinable and can be inversed to calculate the average seal clearance Si. Analysing the obtained results leads to the conclusion that the information about this parameter provides opportunities to monitor the current state of the packing in real time. The applied calculation procedure bases on the de Saint - Venant equation. The article also includes a brief description of both types of seals.

Experimental research and CFD calculations based investigations into gas flow in a short segment of a heavily worn straight through labyrinth seal

Abstract Steam turbines are used as propulsion components in not only power plants but also on merchant and naval ships. The geometry of the steam turbine seals changes throughout the machine life cycle. The rate of deterioration of these seals, in turn, affects heavily the efficiency of the thermal machine. However, the literature overview does not provide any research reports on flow phenomena occurring in heavily deteriorated seals. The paper describes the course and results of investigations into a model straight through labyrinth seal composed of 4 discs, each with the slot height of 2 mm. The investigations have been conducted with air as the working medium. Changes of gas flow parameters due to wear were analysed. Based on the experimental data, more intensive leakage was observed as the result of the increased slot height. The static pressure distribution along the examined segment was measured. The experimentally recorded distribution differed remarkably from the theoretical assumptions. Another part of the experimental research focused on comparing the gas velocities at points situated upstream of the first and second seal disc. The velocity measurements were carried out using a constant temperature wire probe. This part of the investigations provided opportunities for analysing the influence of seal wear on gas flow conditions in the seal segment. The paper compares the results of the experimental research with those obtained using the CFX software. The presented results of velocity distributions provide a clear picture of the nature of the gas flow in the seal, which enables its analysis.

Comparing N3-60 cascade exit angles obtained from tunnel measurements and numerical simulations

Comparing N3-60 cascade exit angles obtained from tunnel measurements and numerical simulations The article compares the results of the measurements performed in the aerodynamic tunnel owned by the Czestochowa University of Technology and the numerical simulation done using the code FLUENT for a plane cascade of N3-60 profiles. The comparison study aims at assessing differences between the exit angles measured experimentally and those obtained from numerical calculations. Variable parameters in the measurements and the calculations were the relative pitch and the profile stagger angle. The measurements were performed in the flow of air. The same medium and having the same inlet parameters was assumed in the calculations. The calculations were performed in two dimensions for the compressible flow. The k-ε RNG turbulence model was used to complete the equation system. Comparing the measured and calculated results provides opportunities for assessing the range of differences between the experiment and the simulation. The obtained results and formulated conclusions will find the application not only in the power industry, but also in the shipbuilding industry for analysing the operation of steam and gas turbines used as main and auxiliary propulsion systems on both merchant vessels and battle ships.

Comparative analysis of energy potential of three ways of configuration of a condenser power plant thermal cycle

Comparative analysis of energy potential of three ways of configuration of a condenser power plant thermal cycle A theoretical, comparative analysis of three configuration ways of a condenser power plant thermal cycle is shown in the work. A new regeneration & separation preheater and its application in a thermal cycle is presented. Results obtained allow to compare all three analysed configurations efficiencies.