Turbine Nozzle Heat Transfer Protrusions for Narrow Airfoil Cooling
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Solution Overview
Problem
Narrower airfoils in turbine nozzles make it difficult to maintain effective cooling with conventional impingement cooling methods, leading to potential overheating issues.
Innovation Solution
A cast turbine nozzle design featuring heat transfer protrusions on the inner surface of the cooling cavity, arranged in a radially staggered columnar pattern along the leading edge, which increases the surface area and enhances heat transfer by disturbing airflow, thereby improving cooling effectiveness without causing turbulence downstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the airfoil is narrowed to make smaller radius leading edges, then the turbine nozzle performance is improved, but the cooling effectiveness deteriorates
Solution Approach 1:
The patent applies heat transfer protrusions specifically at the leading edge region where cooling is most critical, rather than uniformly across the entire airfoil. This localized enhancement of heat transfer surface area and turbulence promotion addresses the cooling deficiency in narrowed airfoils without affecting overall aerodynamic performance.
Solution Approach 2:
The invention transitions from a two-dimensional flat inner surface to a three-dimensional structured surface with heat transfer protrusions. This dimensional change increases the effective heat transfer area and promotes turbulence in the coolant flow, thereby improving cooling effectiveness in the narrowed airfoil configuration.
2Ease of manufacture
If conventional impingement cooling is used in narrower airfoils, then the manufacturing is simpler, but the cooling effectiveness is insufficient
Solution Approach 1:
The patent modifies the geometric parameters of the cooling cavity by introducing heat transfer protrusions with specific dimensions (height, width, spacing) that optimize heat transfer. These parameter changes enhance cooling effectiveness while maintaining compatibility with conventional manufacturing processes for cast turbine nozzles.
3Temperature
If heat transfer protrusions are added to increase surface area, then the heat transfer is enhanced, but the device complexity increases
Solution Approach 1:
The heat transfer surface is segmented into multiple discrete protrusions rather than using a continuous complex structure. This segmentation approach increases heat transfer area while maintaining manufacturing feasibility through standard casting techniques, balancing performance enhancement with 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
The heat transfer protrusions enhance cooling efficiency, maintaining part life, turbine efficiency, and power output by increasing heat transfer exchange relative to a flat surface, while preventing overheating in narrower airfoils.
Implementation Method 1
the inner surface downstream of the plurality of heat transfer protrusions is devoid of the plurality of heat transfer protrusions or other structures that cause turbulence in the coolant flow
Implementation Method 2
the plurality of heat transfer protrusions extending inwardly from the inner surface of the body within the cooling cavity
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A cast turbine (108) nozzle (112) includes an airfoil (130) having a body (128) including a suction side (132), a pressure side (134) opposing the suction side (132), a leading edge (136) spanning between the pressure side (134) and the suction side (132), a trailing edge (138) opposing the leading edge (136) and spanning between the pressure side (134) and the suction side (132), and a cooling cavity (150) defined by an inner surface (152) of the body (128). The nozzle (112) also includes at least one endwall (120, 122) connected with the airfoil (130) along the suction side (132), the pressure side (134), the trailing edge (138) and the leading edge (136), and a plurality of heat transfer protrusions (160) extending inwardly from the inner surface (152) within the body (128), the plurality of heat transfer protrusions (160) extending from the leading edge (136) along the suction side (132) and along the pressure side (134) in a radially staggered columnar pattern. The inner surface (152) includes a planar surface (164) extending between adjacent heat transfer protrusions (160).