Affiliation:
1. University of Bath, Bath, UK
Abstract
The mainstream flow past the stationary nozzle guide vanes and rotating turbine blades in a gas turbine creates an unsteady non-axisymmetric variation of pressure in the annulus radially outward of the rim seal. Ingress and egress occur through those parts of the seal clearance where the external pressure is higher and lower, respectively, than that in the wheel-space; this non-axisymmetric type of ingestion is referred to here as externally-induced (EI) ingress. Another cause of ingress is that the rotating air inside the wheel-space creates a radial gradient of pressure so that the pressure inside the wheel-space can be less than that outside; this creates rotationally-induced (RI) ingress, which — unlike EI ingress — can occur even if the flow in the annulus is axisymmetric. Although EI ingress is usually dominant in a turbine, there are conditions under which both EI and RI ingress are significant: these cases are referred to as combined ingress. In Part 1 of this two-part paper, the so-called orifice equations are derived for compressible and incompressible swirling flow, and the incompressible equations are solved analytically for RI ingress. The resulting algebraic expressions show how the nondimensional ingress and egress vary with Θ0, the ratio of the flow rate of sealing air to the flow rate necessary to prevent ingress. It is shown that ε, the sealing effectiveness, depends principally on Θ0, and the predicted values of ε are in mainly good agreement with available experimental data. Part 2 (ASME GT2009-59122) concentrates on the solution and validation of the orifice equations for EI and combined ingress.
Cited by
11 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
1. Buffer effect of turbine rim cavity on hot gas ingestion;Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy;2022-04-17
2. Numerical Study on Sealing Effectiveness Changes with Increased Turbine Rotor Rim Seal Thickness;Journal of the Korean Society of Propulsion Engineers;2022-02-28
3. Hot gas ingestion in chute rim seal clearance of gas turbine;International Journal of Turbo & Jet-Engines;2021-05-26
4. Hot gas ingestion in chute rim seal clearance of gas turbine;International Journal of Turbo & Jet-Engines;2021-05-26
5. Effect of rotor–stator rim cavity flow on the turbine;International Journal of Turbo & Jet-Engines;2021-05-20