Numerical Investigation of Leakage and Power Loss for Different Seal Types in Turbine Stage Environment

Abstract

In this study, a turbine stage together with diaphragm seals and shroud seals were chosen for numerical investigation. As the baseline design, labyrinth seals’ leakage and blade stage efficiency were analyzed firstly. The results illustrates that as a custom seal, although simplicity, reliableness, and easy replacement make labyrinth seals widely used in steam and gas turbine, but additional power loss caused by excessive leakage flow affects the efficiency of turbine. In order to enhance the efficiency of the turbine stage by leakage reduction, the labyrinth seals at diaphragm and shroud were replaced by brush seals and honeycomb seals respectively. Porous medium method was used to simulate the flow in bristle pack of brush seals, and the pressure drop in bristle was explored by Darcy law. Pressure distribution and flow field details of honeycomb seals were also researched by CFD method. Radial clearance has a direct influence on leakage, so the clearance effect was analyzed in this paper. Lastly, for the stage together with brush seals and honeycomb seals researched, results show that comparing to custom labyrinth seals, the reduction leakage was approximate 30% and the improvement of stage efficiency was 0.6%.

Research of influence of random change of annular seal parameters on efficiency of centrifugal pump

“…CFD modeling of "short" and "long" annular seal with taking into account shaft precession and determination and analysis of hydrodynamic characteristics of seals is carried out in [10]. In [11] numeral research of the fields of velocities and pressure in seals with different roughnesses of sealing surfaces and in labyrinth seals is made. Numeral methods allow not only to increase exactness of calculation but also to solve the problem of optimization of leakage through annular seal, as it is done, for example, in [12].…”

“…Taking into account dependences (7) and (11), the latter correlation can be solved with respect to pressure drop: As Δp is a one-valued function η v in the area of possible values Δp, η v , an integral (12) can be brought to the triple integral with the set limits of integration:…”

Research on unsteady aerodynamic performance of last stage for low pressure cylinder of steam turbine

“…Currently, in most high-power turbine, 30 % power of the entire unit is all provided by the low pressure cylinder. Therefore, the safe and efficient operation is important for improving the aerodynamic performance of the turbine, reducing the eddy current loss and improving efficiency of the steam turbine unit [8][9][10][11].…”