Non-axisymmetric Turbomachine Flow Contour for Wheelspace Cooling
Solution Overview
Problem
Current turbomachine designs experience efficiency losses due to strong secondary flows in turbine stages, which are not effectively addressed by existing non-axisymmetric endwall contouring that only targets gas path surfaces.
Innovation Solution
Incorporating non-axisymmetric flow contour features that extend from gas path surfaces to non-gas path surfaces within the turbomachine, altering local pressures to prevent hot gas ingestion into the wheelspace and reduce the need for additional purge flows, thereby enhancing backflow margins and maintaining cooler temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If non-axisymmetric endwall contouring is used to reduce secondary flow losses, then stage efficiency is improved, but it only addresses gas path surfaces and does not effectively control secondary flows in the wheelspace
Solution Approach 1:
The flow contour feature extends from the gas path surface into the wheelspace dimension, creating a three-dimensional structure that addresses secondary flows in both regions. This dimensional extension allows the contouring to control flows that were previously unaddressed by traditional two-dimensional endwall contouring.
Solution Approach 2:
The flow contour feature serves multiple functions: it reduces secondary flow losses in the gas path, controls secondary flows in the wheelspace, and maintains cooler temperatures in the wheelspace. This multi-functionality resolves the limitation of previous designs that only addressed gas path surfaces.
2Productivity
If traditional endwall contouring is applied, then gas path flow is improved, but wheelspace temperatures remain high requiring additional purge flows
Solution Approach 1:
The flow contour feature creates localized flow control with different effects in different regions: it improves gas path flow efficiency while simultaneously creating cooler conditions in the wheelspace region. This local differentiation addresses both temperature control and efficiency without requiring additional purge flows.
Solution Approach 2:
The contouring that would normally only benefit gas path flow is extended to also benefit wheelspace temperature control. The same geometric feature that reduces secondary flow losses also creates favorable pressure gradients that prevent hot gas ingestion into the wheelspace, converting a single-function design into a dual-benefit solution.
3Temperature
If wheelspace purge flows are increased to maintain cooler temperatures, then temperature control is improved, but compressor flow to the turbine is reduced
Solution Approach 1:
The flow contour feature creates self-regulating flow patterns that naturally maintain cooler wheelspace temperatures through favorable pressure distributions, eliminating the need for external purge flows. The geometry itself provides the temperature control function, allowing maximum compressor flow to reach the turbine.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The non-axisymmetric flow contour features effectively reduce secondary flow losses and maintain cooler temperatures in the turbomachine wheelspace, allowing for increased compressor flow to be directed to the turbine portion for enhanced shaft work generation without the need for additional purge flows.
Implementation Method 1
altering local pressures to prevent hot gas ingestion into the wheelspace
Implementation Method 2
strong secondary flows in which high energy and high temperature fluids flow in a direction transverse to a main flow direction
Implementation Method 3
maintain cooler temperatures in the turbomachine wheelspace
Data Source
Figure 1
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Figure 3
AI summary
A turbomachine component includes a main body (52) having a gas path surface (71,73) configured to be exposed to gases passing along a turbomachine gas path (61), a non gas path surface (77) configured to be arranged in a turbomachine wheelspace outside the turbomachine gas path, and a non-axisymetric flow contour feature (94) extending from the gas path surface (71,73) to the non gas path surface (77).