Impingement Cooled Wall Arrangement with Aligned Turbulators
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Solution Overview
Problem
Current impingement cooling methods for gas turbine duct walls face efficiency penalties due to cross-flow buildup, which reduces heat transfer coefficients and leads to non-uniform heat loads, particularly in areas with increased heat exposure like combustion chambers.
Innovation Solution
The proposed impingement cooled wall arrangement features a combination of apertures and turbulators, where the apertures are aligned with the leading edges of turbulators, primarily in the upstream section, to enhance heat transfer and maintain efficiency along the wall, reducing the need for downstream apertures and thus minimizing cross-flow interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of impingement rows is increased towards the end of the cooling flow path, then the cooling coverage is improved, but the cross flow in the cooling channel builds up and hinders the heat transfer coefficients
Solution Approach 1:
The cooling system is segmented into two distinct zones: an upstream section with impingement rows that provides direct cooling, and a downstream section with turbulators that manages cross-flow. This segmentation allows each zone to optimize its function without interfering with the other, resolving the contradiction between cooling coverage and heat transfer efficiency.
Solution Approach 2:
Turbulators are introduced as intermediary elements in the downstream section. These turbulators act as mediators that control and redirect the cross-flow, preventing it from diverting the impingement jets away from the wall. This allows the system to maintain high heat transfer coefficients while still providing extended cooling coverage.
2Productivity
If the height of the cooling channel is increased to limit cross flow velocity, then the cross flow is reduced, but the impingement effect of the jet reaching the duct wall is reduced
Solution Approach 1:
Different sections of the cooling channel are given different qualities and functions. The upstream section maintains a configuration optimized for impingement cooling with direct jet-to-wall contact, while the downstream section incorporates turbulators to manage cross-flow. This local differentiation allows the system to maintain high impingement effectiveness without being constrained by cross-flow velocity limitations throughout the entire channel.
3Reliability
If additional impingement holes are added to increase cooling capacity, then the cooling coverage is improved, but the device complexity increases
Solution Approach 1:
The turbulators serve multiple functions: they control cross-flow velocity, redirect coolant flow patterns, and enhance mixing in the downstream section. By making these elements multi-functional, the system achieves improved cooling capacity without proportionally increasing the number of apertures or overall device complexity.
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 design maintains high heat transfer coefficients and uniform cooling efficiency along the wall, reducing the required coolant mass flow and pressure drop, while extending part life and potentially lowering manufacturing costs by optimizing heat transfer without increasing system pressure.
Implementation Method 1
compressed gas injected from the plenum through the plurality of apertures in the impingement sleeve during operation impinges on the wall and flows as a cross flow towards an exit at a downstream end of the cooling flow path
Implementation Method 2
flows as a cross flow towards an exit at a downstream end of the cooling flow path
Implementation Method 3
a plurality of turbulators having a leading edge arranged on the wall. The center of at least one of the apertures is aligned along the longitudinal axis with the leading edge of at least one of the turbulators
Data Source
Figure 1~2b
Figure 3~4
Figure 5~6
AI summary
The present disclosure refers to an impingement cooled wall arrangement (12) comprising: an impingement sleeve (10) and a wall (7) exposed to a hot gas (19) during operation, wherein the impingement sleeve (10) is at least partly disposed in a plenum (20), and spaced at a distance from the wall (7) to form a cooling flow path (15) between the wall (7) and the impingement sleeve (10) such that compressed gas (11) injected from the plenum (20) through the plurality of apertures (13) in the cooling sleeve during operation impinges on the wall (7) and flows as a cross flow (16) towards an exit at a downstream end (28) of the cooling flow path (15); and a plurality of turbulators (21) having a leading edge (25) arranged on the wall (7), characterised in that the center of at least one of the apertures (13) is aligned along the longitudinal axis (29) with the leading edge (25) of at least one of the turbulators (21). Besides the impingement cooled wall arrangement (12) a gas turbine (1) with such an arrangement as well as a method for cooling a duct wall are disclosed.