Turbine Vane Rib Cavity Heat Exchange Reduction
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Solution Overview
Problem
Hollow gas turbine blades experience excessive heat exchange with hot gases due to the presence of a cavity, leading to thermal stress on the walls, which is not effectively managed by existing designs.
Innovation Solution
Incorporating at least one rib on the lateral periphery of the cavity, oriented substantially perpendicular to the radial direction, which blocks the entry of hot gases and reduces heat exchange by creating counter-rotating gas circulations and edge effects, thereby confining gases and minimizing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a cavity is provided in the turbine blade to lighten it and modify gas flow, then the blade weight is reduced and gas flow from lower surface to extrados is limited, but hot gases heat the cavity walls by convection causing thermal stress
Solution Approach 1:
The cavity is segmented by introducing ribs that divide the continuous cavity space into separated regions. This segmentation creates flow barriers that prevent hot gases from directly contacting and heating the cavity walls, while maintaining the weight reduction benefit of the hollow structure
Solution Approach 2:
Ribs are introduced as intermediary structures within the cavity that act as flow barriers. These ribs intercept hot gases before they can reach the cavity walls, mediating the interaction between hot gases and cavity walls to reduce thermal stress
2Temperature
If ribs are added to block hot gas entry into the cavity, then heat exchange between hot gases and cavity walls is reduced, but the added mass of the blade increases
Solution Approach 1:
Rather than adding substantial structural elements throughout the blade, ribs are strategically placed only at critical locations where hot gas intrusion occurs. This localized approach provides thermal protection precisely where needed while minimizing the overall added mass of the blade
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 rib configuration effectively reduces heat exchange between hot gases and the cavity walls, leading to reduced thermal stress and improved thermal homogeneity, while also lightening the blade and minimizing added mass.
Implementation Method 1
the hot gases coming from the combustion chamber located upstream of the turbine, heat the walls of the cavity 14 by convection by circulating inside the cavity 14
Implementation Method 2
said at least one rib on the lateral periphery generates a circulation of gas which blocks the entrance to the cavity to the majority of the hot gases liable to penetrate therein
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4D
AI summary
The invention relates to a turbine vane (10) that extends radially between a vane base and a vane top (12) in which a vent cavity is provided, referred to as a tub (14), defined by a closed bottom (16) and a lateral circumference (18). The lateral circumference (18) of the cavity (16) has at least one rib (32) extending between a leading edge (28) and a trailing edge (30) of the vane (10).