Turbine Blade Pin-Fin Array with Chamfered Ends
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Solution Overview
Problem
The trailing edge of turbine blades in gas turbines is structurally weak due to their airfoil shape, making it challenging to enhance cooling performance and mechanical strength, especially at high turbine inlet temperatures, where material deterioration and stress concentration occur.
Innovation Solution
A turbine blade design featuring a pin-fin array with selectively chamfered or filleted pin-fins in the internal cooling passages connected to the trailing edge slot, where pin-fins with larger chamfered or filleted portions are positioned in the inner corner region to improve mechanical strength without compromising cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling slots are increased in size at the trailing edge to improve cooling performance, then cooling efficiency is improved, but structural strength of the trailing edge deteriorates
Solution Approach 1:
The pin-fins are selectively positioned only in specific regions of the internal cooling passage (such as near the trailing edge or in high-heat-flux zones) rather than uniformly throughout. This local placement provides enhanced cooling where needed while preserving structural integrity in other critical areas of the blade
Solution Approach 2:
The pin-fin array creates an asymmetric internal structure within the cooling passage, with pin-fins strategically positioned to optimize cooling flow patterns. This asymmetric arrangement improves heat transfer efficiency without requiring symmetric reinforcement that would add weight and complexity to the already complex trailing edge structure
2Power
If the turbine inlet temperature is increased to improve thermodynamic efficiency, then power output and efficiency are improved, but material deterioration and mechanical strength worsen
Solution Approach 1:
The pin-fins act as intermediary heat transfer elements within the internal cooling passage, facilitating more efficient heat removal from the blade metal to the cooling air. This enhanced heat transfer mediation allows the blade to withstand higher inlet temperatures by effectively managing thermal loads through the intermediate cooling fluid
Solution Approach 2:
The introduction of pin-fins changes the thermal and flow parameters within the internal cooling passage, creating turbulence and improving convective heat transfer coefficients. This parameter change in the cooling system enables the blade to operate at higher inlet temperatures without exceeding material temperature limits
3Temperature
If pin-fins are added to the internal cooling passage to improve cooling performance, then heat transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling system is segmented into distinct functional zones: regions with pin-fin arrays for enhanced heat transfer and regions without pin-fins for simplified structure and manufacturing. This segmentation allows optimization of cooling performance in critical areas while maintaining manufacturing feasibility and reducing overall complexity
Solution Approach 2:
The pin-fin structure serves multiple functions simultaneously: it enhances heat transfer, directs cooling flow patterns, and can be integrated with the blade's existing cooling passage geometry. This multi-functionality reduces the need for additional separate cooling components, thereby limiting the increase in 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 enhances the mechanical strength of the trailing edge while maintaining effective cooling performance, minimizing design changes and ensuring the turbine blade can withstand high temperatures and dynamic pressures.
Implementation Method 1
cooling air flows through internal cooling passages
Implementation Method 2
cooling air in an internal cooling passage of the turbine blade is ejected to cause an impingement cooling
Implementation Method 3
various types of outlets are disposed in several places to form an effective film cooling on the surface
Data Source
AI summary
A turbine blade includes a blade extending from a platform to a free end and having an airfoil-shaped cross section, the blade including a leading edge, a trailing edge, a pressure side extending from the leading edge to the trailing edge, and a suction side extend-ing from the leading edge to the trailing edge, one or more internal cooling passages through which cooling air flows, a trailing edge slot formed along the trailing edge and con-nected to the internal cooling passage, and a pin-fin array including a plurality of pin-fins positioned in the internal cooling passage connected to the trailing edge slot, each pin-fin including a main body and chamfered or filleted portions respectively connected to the pressure side and the suction side at respective ends of the main body, wherein among the pin-fins of the pin-fin array, a portion of the pin-fins have relatively large chamfered or filleted portions as compared with remaining pin-fins.