Labyrinth seals with application to turbomachinery

Abstract

It is well known that there exist losses of fluid through axial and radial gaps in turbomachines, leading to less efficiency. Every 1 % decrease in leakage flow through a high‐pressure gas turbine seals would result in a 0.4 % decrease in the specific fuel consumption [1]. Last decades, a number of solutions have been applied to overcome losses of fluid through axial and radial gaps. A feasible solution is the application of labyrinth seals to act as an obstacle on the way of flow leakages. This research is targeted to attain a seal configuration that has good dynamic sealing properties, higher compliance with the shaft, simple geometry for manufacturing and maintenance. The labyrinth seal must produce significant losses of kinetic energy in order to stop leaks passing through the sealed places. It is known that the turbine shaft exhibits modal and stress loads. Also, seals must be designed to resist loads and operate at maximum efficiency. The fulfilled numerical analysis shows that the proposed geometry causes intensive reduction of leakage flow rates and thus contributes to increase in the efficiency performance of stages under consideration.

On CFD Investigation of Radial Clearance of Labyrinth Seals of a Turbine Engine

“…It also has a wall function for a better description of the boundary layer. Similar results can be found in [2] and [9].…”

“…Thanks to the labyrinth seals, it is possible to direct the air flow to the parts of the engine where it can be useful -which means decrease the axial force of the shaft, etc. (see [2]). In numerical analysis, it is important to correctly design and define the cavity between the rotating and non-rotating parts, because the tooth profile has an important influence at high Mach numbers (see [1,3]).…”

Labyrinth Seal of Aircraft Turbine Engine Air Flow Calculation at High Viscosity

“…After calculation it was found, that the total temperature was increased which is contrary with [1] -similar results was presented in [8]. But the previously literature ( [5] and [7]) was analyzed steam turbines labyrinth seal application. In aircraft turbine engine are different conditions.…”

“…Between these two elements is located the air flow cavity where is the air flow of the gas. As apparent from the picture the important parts are profile of the teeth, rotational speed and radial clearance between the rotating and non-rotating parts [5]. With precision settings of the radial clearances and geometry of the flow cavity it should be possible to improve the performance parameters of the engine.…”

Aircraft Turbine Engine Labyrinth Seal CFD Sensitivity Analysis

“…In steam turbines, the velocity is approximately 500 rad/s and, in turbine engines, it is approximately 4100 rad/s [1,7,8]. Literature sources addressing the topic are rather rare [9][10][11]. In the presented article, the influence of different settings of the radial clearance and different locations of the teeth are examined, developing the previous research presented in [12].…”