Wyniki wyszukiwania - BazTech

1

Repairability analysis of the energy gas turbine rotor blade second stage shroud by high-temperature brazing

Klimczuk Piotr

Welding Technology Review

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2021

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R. 93, nr 2

23--31

EN

The article considers the repair of the energy gas turbine rotor blade second stage shroud. The paper presents an analysis of the possibility of the repair consisting of the replacement of both labyrinth and honeycomb seals by the high-temperature brazing process. All the steps of the repair process were discussed and the results of microscopic metallographic evaluation using a light microscope and a scanning electron microscope were presented. SEM BSE microstructure and elements distribution of the joints has been presented. Several advantages related to the use of this technology were indicated.

PL

W artykule omówiono tematykę regeneracji osłony łopatki wirnika drugiego stopnia energetycznej turbiny gazowej. Przedstawiono analizę możliwości jej naprawy polegającej na wymianie zarówno uszczelnień labiryntowych jak i ulowych z zastosowaniem procesu lutowania wysokotemperaturowego. Omówiono poszczególne etapy procesu naprawy oraz zaprezentowano wyniki badań metalograficznych mikroskopowych z użyciem mikroskopu świetlnego oraz elektronowego mikroskopu skaningowego. Wskazano na szereg korzyści związanych ze stosowania tej technologii.

2

Research of air movement in the labyrinth seal of rollers of conveyor belt

Kononov G., Artemov S., Dubrovskyi S., Kravtsova D.

Archive of Mechanical Engineering

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2019

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Vol. LXVI, nr 4

439--445

EN

In the paper, the authors present the solution aimed at increasing reliability of the conveyor units. The analysis of technological and operational defects of conveyor rollers is presented. The changes in manufacturing technology have been proposed, which allowed for avoiding welding and provided the required level of tightness. Computer simulation of the motion of air in the labyrinth seal of the roller was conducted to determine the numerical parameters of possible airflows. It is proved that the airflow is present in the gap of the labyrinth seal due to the roller rotation. It is shown that the reason for the penetration of abrasive particles through the labyrinth seal after stopping is decompression, which occurred as a result of temperature change and push out of airflows during rotation. It is also suggested that the number of stops during the operation should be taken into account when determining the durability of rollers. Practical recommendations are given for preventing the penetration of abrasive particles during conveyor stops and the need for combined seals. The results can be used for the construction of roller conveyor belts in any industry.

3

What-if analysis of the labyrinth seal of the gas turbine rotor tip

Wróblewski W., Bochon K., Borzęcki T.

Transactions of the Institute of Fluid-Flow Machinery

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2017

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nr 136

3--21

EN

This paper presents a preliminary, numerical what-if analysis of selected geometrical parameters of the tip seal of the last stage of an aircraft engine turbine and the impact of the parameters on the leakage mass ow. The analysis is a part of the task of improving the rotor tip seal conguration in aircraft turbines. Calculations were carried out using the commercial computational uid dynamics code. A straight-through seal with two leaning ns and a honeycomb land was analysed. The computational model was prepared based on some simplications introduced to improve the eciency of the calculations. The rotor entire blade-to-blade channel was analysed, while the seal pitch was reduced to the dimensions of two honeycomb cells. The geometry of the ns themselves was simplied too. In the original variant, the n tips had caps to protect them from wear (shape deformation) due to rubbing. In the simplied model, the caps were omitted. The simplications did not change the leakage mass ow signicantly. Several variants of changes in the basic geometrical parameters of the seal were analysed to assess their eect on the leakage mass ow for altered ow conditions. Parameters such as the n thickness, the n inclination angle and the position of the ns and of the entire labyrinth were analysed. The best seal variant was selected, the ow phenomena were commented on and some points in the design of this type of the labyrinth seal were discussed.

4

Metamodel-Based Optimization of the Labyrinth Seal

Rulik S., Wróblewski W., Frączek D.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 1

75--91

EN

The presented paper concerns CFD optimization of the straight-through labyrinth seal with a smooth land. The aim of the process was to reduce the leakage flow through a labyrinth seal with two fins. Due to the complexity of the problem and for the sake of the computation time, a decision was made to modify the standard evolutionary optimization algorithm by adding an approach based on a metamodel. Five basic geometrical parameters of the labyrinth seal were taken into account: the angles of the seal’s two fins, and the fin width, height and pitch. Other parameters were constrained, including the clearance over the fins. The CFD calculations were carried out using the ANSYS-CFX commercial code. The in-house optimization algorithm was prepared in the Matlab environment. The presented metamodel was built using a Multi-Layer Perceptron Neural Network which was trained using the Levenberg-Marquardt algorithm. The Neural Network training and validation were carried out based on the data from the CFD analysis performed for different geometrical configurations of the labyrinth seal. The initial response surface was built based on the design of the experiment (DOE). The novelty of the proposed methodology is the steady improvement in the response surface goodness of fit. The accuracy of the response surface is increased by CFD calculations of the labyrinth seal additional geometrical configurations. These configurations are created based on the evolutionary algorithm operators such as selection, crossover and mutation. The created metamodel makes it possible to run a fast optimization process using a previously prepared response surface. The metamodel solution is validated against CFD calculations. It then complements the next generation of the evolutionary algorithm.

5

Ocena niestacjonarnego pola przepływowego w uszczelnieniu labiryntowym przy użyciu metod numerycznej mechaniki płynów

Szymański A., Dykas S.

Modelowanie Inżynierskie

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2016

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T. 28, nr 59

76--85

PL

W artykule przedstawiono analizę numeryczną niestacjonarnego pola przepływowego w modelu turbinowego uszczelnienia labiryntowego w rzeczywistych warunkach pracy dla dwóch różnych struktur uszczelnienia labiryntowego z okładziną o strukturze plastra miodu oraz ze ścianą gładką. Oprócz strat przecieku, obszar ten jest szczególnie istotny z uwagi na zjawisko generacji hałasu szerokopasmowego powstałego w wyniku turbulentnych zjawisk przepływowych. Wyniki przedstawiono jako wielkości akustyczne w funkcji częstotliwości. Pozwoliło to na określenie częstotliwości głównych, przy których zaistniały ich szczytowe wartości. Dodatkowo porównano zmianę bezwymiarowej wartości przecieku w czasie. Wyniki obliczeń wskazały wpływ zastosowanej struktury uszczelnienia na tłumienie fluktuacji ciśnienia oraz wartości przecieku przy różnych prędkościach obrotowych wirnika.

EN

This work aims to perform detailed time-dependent flow analysis of gas turbine stage model equipped with tip labyrinth seal against honeycomb or smooth land, in order to identify the noise generated aerodynamically. Two different sealing structures were investigated – honeycomb structure and smooth land. The main scopes of this investigation were evaluation of unsteady flow field behaviour, indication regions were the vorticity and broadband noise is generated. Also an impact of the sealing structure on the flow behind the rotor was checked. To evaluate results, acoustic pressure – p’ and Sound Pressure Level (SPL) values were used. Discharge coefficient, as a measure of non-dimensional leakage has also been inquired and compared. The results shown an influence of honeycomb structure, and rotational velocity of rotor on pressure fluctuations and noise damping.

6

Nowe narzędzia badawcze w badaniach uszczelnień labiryntowych

Prońska A., Kiciński J.

Problemy Eksploatacji

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2005

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nr 3

235--246

PL

W IMP PAN w Gdańsku od lat prowadzone są badania symulacyjne w oparciu o własny system komputerowy, którego najnowsza generacja pozwoliła na zbudowanie pseudoliniowego i w pełni nieliniowego modelu uszczelnień. W pracy przedstawiono możliwości zastosowań obydwu modeli stawiając sobie za cel nie tyle przeprowadzenie systematycznych badań, ile wskazanie pola zastosowań opracowanych narzędzi badawczych.

EN

As a result of a long-term research carried out at IFFM models and computer codes (NLDW) for nonlinear analysis of dynamical properties of the rotating machines have been developed. The newest generation of the codes enabled introduction of seals in linear and nonlinear way. In the paper presented have been a so called "pseudolinear" and "nonlinear" method of seals investigation. The examples presented in the paper indicate the wide possibilities of NLDW system application in the investigation of dynamical properties of large and small rotating machines accounting for the forces generated in seals.