Slanted Ribs with Slits for Cooling Passage Heat Transfer
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Solution Overview
Problem
Existing internal cooling passage designs with ribs suffer from large recirculation zones at the downstream side of ribs, which reduce heat transfer efficiency and deteriorate the overall heat transfer performance of members such as gas turbine blades.
Innovation Solution
The design incorporates first and second ribs that extend from the center between opposed wall surfaces and slant in the downstream direction of the medium flow, with openings between the upstream and downstream sides of these ribs, reducing recirculation zones by promoting turbulence and efficient air flow through slits or divisions in the ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ribs are provided in the internal cooling passage arranged in a staggered manner, then turbulent flow is caused in the medium on the heat transfer surface to obtain a large cooling heat transfer coefficient, but a large recirculation zone exists at the downstream side of the rib which does not contribute to heat transfer and deteriorates heat transfer performance
Solution Approach 1:
The rib structure is segmented by providing openings (slits) in the ribs, dividing the continuous rib into sections. This segmentation allows the medium to pass through the rib, reducing the recirculation zone at the downstream side while maintaining the turbulence-enhancing effect on the heat transfer surface.
Solution Approach 2:
Openings are extracted from the rib structure to remove the harmful recirculation zone. The openings allow the medium to flow through the rib, extracting the problematic recirculation flow and replacing it with productive flow that contributes to heat transfer.
2Loss of energy
If ribs are divided to reduce recirculation zone, then the recirculation zone at the downstream side of the rib is reduced, but the interval between the divided rib pieces is large causing the medium to flow directly through the opening
Solution Approach 1:
The rib structure is designed with local variations: the ribs have different heights, and openings are selectively positioned at specific locations rather than uniformly distributed. This local quality optimization ensures that the medium is effectively redirected to contribute to heat transfer while minimizing direct flow through openings.
Solution Approach 2:
The rib structures are arranged in multiple dimensions including different heights and staggered positions. This multi-dimensional arrangement controls the medium flow path more effectively, ensuring that flow through openings contributes to heat transfer rather than creating large recirculation zones.
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
This configuration enhances heat transfer performance by reducing recirculation zones and pressure loss, allowing for more efficient cooling of gas turbine blades with a smaller quantity of cooling air, thereby improving heat efficiency.
Implementation Method 1
a method of causing turbulence flow in air flow of a heat transfer surface
Implementation Method 2
a medium flows to cool a parent material
Data Source
AI summary
Provided is a member having an internal cooling passage 7c formed therein and having opposed partition walls 6b, 6c between which a medium flows to cool a parent material, including a first heat transfer rib 25a which extends from almost the center between the opposed partition walls 6b, 6c to one partition wall 6c and slants in a downstream direction of the medium, and a second heat transfer rib 25b which extends from almost the center between the opposed partition walls 6b, 6c to the other partition wall 6b and slants in the downstream direction of the medium, wherein a slit 70a or 70b which passes through between an upstream side of the cooling passage 7c and a downstream side thereof is formed in the first heat transfer rib 70a or the second heat transfer rib 70b.