Passage channel for a turbomachine and turbomachine

Abstract

A transition duct for a turbomachine, in particular an aircraft engine, for forming a flow channel between an upstream flow cross section and a downstream flow cross section, including supporting ribs which extend between a radially inner duct wall and a radially outer duct wall and each of which has a profile for deflecting a flow from an inlet area to an outlet area of the transition duct, the supporting ribs each having a profile variation in the area of their trailing edge and / or at least one blow-out opening for blowing out a fluid; also disclosed is a turbomachine having a transition duct of this type.

Description

[0001]This claims the benefit of European Patent Application EP 12170498.5, filed Jun. 1, 2012 and hereby incorporated by reference herein.[0002]The present invention relates to a transition duct for a turbomachine as well as a turbomachine.BACKGROUND[0003]A transition or deflecting duct in an axial turbomachine, such as an aircraft engine, conducts a main flow from an upstream flow cross section to a radially offset flow cross section. The transition duct usually has an annular cross section and is situated, for example, between a high pressure turbine and a low pressure turbine (turning mid turbine frame—TMTF). In a three-part design of a turbine, the transition duct may also be situated between a high pressure turbine and an intermediate pressure turbine as well as between the intermediate pressure turbine and a low pressure turbine. In compressors, a transition duct may similarly conduct the flow from an upstream flow cross section to a downstream flow cross section and be situa...

AI Technical Summary

Benefits of technology

The present invention provides a transition duct for a turbomachine that improves the mixing of airflow and reduces energy transmission losses, leading to a higher efficiency and lower noise development. The unique design profile variation and at least one blow-out opening create a passive and active wake mixture, which leads to a calming of the flow and minimizes aerodynamic excitations of the rotor blades. A suction-side partial flow and pressure-side partial flow are equalized with regard to their outflow speed, reducing eddies and improving the wake flow. The at least one blow-out opening ensures uniform fluid blowing and prevents a deflection of the partial flows. Additionally, a flow splitter blade may be added between the supporting ribs to reduce eddies, flow losses, and deflection limitations. Overall, this transition duct design results in improved energy conversion, reduced noise, and improved efficiency of the turbomachine.

Problems solved by technology

However, such a geometry of the supporting ribs results in heavy secondary flows.

In particular, they may limit a maximum possible deflection on the hub and housing and result in energy transmission losses.

In addition, secondary flows may result in excitations of the first moving blade row of the downstream turbine and thus in high noise development.

Moreover, the number of blades of the transition ducts, which is much smaller compared to conventional stator geometries, may cause aerodynamic excitations of the subsequent rotor blades having fundamental modes, so-called engine orders, in the working area of the turbomachine.

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