Artur Szymański

Experimental and numerical validation study of the labyrinth seal configurations

This article presents a validation study of the labyrinth seal testing. Both experimental and numerical simulations are performed. Literature data focused on simple labyrinth seals are surveyed, and two different configurations widely described in literature are investigated: a labyrinth seal with two straight fins against a smooth and a honeycomb land and a seal with three straight fins against a smooth land only. For experimental testing the vacuum-feeding test rig is used, with the high-precision Hot Wire Thermoanemometry method applied for the mass flow evaluation. The dimensions of specimens described in literature are adapted to the in-house test rig conditions, meeting all the geometrical requirements mentioned by the author. The computational method is based on the Reynolds Averaged Navier Stokes scheme, with various turbulence models. The results of the simulations show good agreement with the in-house experiment, whereas some discrepancies are found compared to literature data.

Experimental and numerical study on the performance of the smooth-land labyrinth seal

In turbomachinery the secondary flow system includes flow phenomena occurring outside the main channel, where the gaseous medium performs work on blades. Secondary air distribution constitutes a very complex and closely interrelated system that affects most of the gas turbine components. One of the most important examples of the secondary flow is leakage occurring in seals, e.g. at the rotor and stator tips, on the shaft or on the sides of the blade rim. Owing to its simplicity, low price, easy maintenance and high temperature capability, the labyrinth seal is a prime sealing solution that may be selected from numerous types of sealing structures applied in turbomachinery. For this reason, an experimental study of this particular structure has been carried out. The paper presents leakage performance of the smooth-land labyrinth seal.

Investigation of the tip-leakage losses in turbine axial stages

In turbomachinery, an influence of a tip-leakage flow on overall blade loss is crucial and its reduction is still worth striving for. In this paper a numerical analysis of the flow in tip seal of high-rotating gas turbine engine has been made. This analysis is a part of experimental research for testing the commercially used different tip seals solutions. Described test rig is predicted to be an universal tool for developing and examining different configurations of turbine blade tips. Presented numerical analysis is used to predict physical phenomena that may affect the rotor blade performance. In the numerical investigation the commercial Ansys CFX software was employed. The most important parameters were: mass flow rate at the inlet and outlet of the test bench, pressure and velocity distribution and the air temperature growth above the rotor. Also, an influence of test rig inlet and outlet geometry on flow uniformity was investigated. During the analysis the attention was focused also on minimizing the turbulence intensity in outlet area, that could cause significant difficulties in flow and stable work of the machine – generated eddies contributes to lower the mass flow rate.