Blade Grid Platform Trough Contouring for Lower Pressure Loss
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Solution Overview
Problem
Existing turbomachinery designs suffer from secondary currents and eddies in the annular space, leading to increased pressure losses and inefficiencies.
Innovation Solution
A blade grid section with a platform surface featuring a trough that decreases radially from the suction side to the pressure side of adjacent blades, minimizing secondary flow and reducing vortices by maintaining a maximum radial position equal to or below an uncontoured reference surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sidewall contours with raised areas and/or depressions are incorporated into the side walls, then secondary currents are reduced, but device complexity increases
Solution Approach 1:
The platform surface is differentiated into distinct regions: a first region with a first contour and a second region with a second contour, where each region has different contour characteristics. This local differentiation allows optimization of flow characteristics in specific areas without complicating the entire structure, thereby reducing secondary currents while managing device complexity through targeted modifications rather than uniform changes throughout the component.
2Productivity
If the platform surface is made contoured with multiple regions, then flow efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The platform surface is segmented into a first region and a second region, each with distinct contour characteristics. The first region has a first contour and the second region has a second contour, allowing independent optimization of each segment. This segmentation enables improved flow efficiency through region-specific flow management while simplifying manufacturing precision requirements by breaking down the complex overall geometry into manageable segments that can be manufactured separately or with different tolerance requirements.
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 design effectively reduces secondary flows and vortices, enhancing flow efficiency and reducing pressure losses, while also potentially improving noise emissions.
Implementation Method 1
Flow layers close to these surfaces are deflected more strongly due to their lower velocity than flow layers further away from the side walls. This creates a secondary flow superimposed on the axial main flow, leading in particular to eddies and pressure losses.
Implementation Method 2
contours in the form of raised areas and/or depressions are often incorporated into the side walls. The trough is configured such that its bottom is a global minimum, and in another embodiment, the radial position of the trough decreases in the circumferential direction from the suction side of one (first) of the at least two blades to the pressure side of the adjacent other (second) of the at least two blades
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a blade grid section (1) for a blade grid of a turbomachine, wherein the blade grid section comprises a platform (10) with a platform surface and an upstream platform edge (10a) as well as at least two circumferentially adjacent blades (20, 30) which, by means of their leading and trailing edges (23, 33, 24, 34) on the platform surface, define a blade intermediate strip (11) with axial grid width (g), wherein the platform surface of the blade intermediate strip has a trough (15) with a bottom, wherein the trough (15) is configured such that the bottom of the trough (15) is a global minimum (14) of the trough (15) and a radial position of the trough (15) in the circumferential direction (U) from a suction side of one of the at least two blades (20, 30) to the pressure side of the adjacent other of the at least two blades (20, 30).30) decreases with respect to a reference surface towards the bottom of the trough (15) and increases from there in the circumferential direction (U), at most up to the radial position of the reference surface, and wherein a radial position of the trough (15) decreases in the axial direction downstream with respect to the reference surface towards the bottom of the trough (15) and increases from there in the axial direction downstream, at most up to the radial position of the reference surface, and wherein the platform surface of the blade intermediate strip (11) assumes at most a radial position of the reference surface, wherein the reference surface corresponds to an uncontoured platform surface.