Gas Turbine Blade Internal Cooling Structure Core Removal
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Solution Overview
Problem
The existing designs for internal cooling structures in gas turbine blades face challenges in efficiently removing ceramic core material during the leaching process, leading to potential residual material obstruction and reduced cooling efficiency, while also being costly and complex to manufacture.
Innovation Solution
A gas turbine blade design with an internal cooling structure featuring three longitudinal passages connected by 180° turns, an open channel at the root region for complete core material removal, and strategically arranged trip strips at specific angles to optimize airflow and compensate for hydraulic pressure losses, ensuring efficient cooling without closing the opening at the 180° turn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional internal cooling structures with 180° turns are used, then cooling performance can be achieved, but residual core material obstructs the flow and manufacturing becomes difficult
Solution Approach 1:
The patent applies preliminary action by designing the cooling passage geometry and positioning the outlet opening such that core material is naturally flushed out during the leaching process before final assembly. The outlet opening is strategically placed to enable complete removal of ceramic core material through natural flow dynamics, preventing obstruction issues before they occur.
Solution Approach 2:
The patent extracts the problematic 180° turn configuration that traps core material and replaces it with a simplified passage design where the outlet opening directly enables core material extraction. The cooling passages are redesigned to allow complete leaching of ceramic material without requiring complex closing mechanisms.
2Ease of manufacture
If opening is provided for core material removal, then complete leaching is enabled, but cooling structure complexity increases and aerodynamics are affected
Solution Approach 1:
The outlet opening serves multiple functions: it enables complete core material removal during manufacturing, maintains streamlined cooling passage geometry, and preserves aerodynamic efficiency. By integrating the outlet opening directly into the cooling passage structure rather than adding separate removal mechanisms, the design achieves multi-functionality without increasing overall complexity.
Solution Approach 2:
Instead of closing the outlet opening after core material removal as in traditional designs, the patent inverts the approach by leaving the opening open to serve as the cooling air outlet. This reversal simplifies the structure by eliminating the need for closing mechanisms while maintaining both manufacturing ease and operational cooling function.
3Temperature
If cooling air is bled from compressor, then blade cooling is achieved, but overall engine performance is reduced
Solution Approach 1:
The patent optimizes the cooling structure geometry including passage cross-sections, lengths, and the outlet opening position to maximize cooling efficiency. By carefully designing the passage parameters and ensuring complete core material removal to prevent flow obstruction, the system achieves effective blade cooling with minimized air consumption, thereby reducing the negative impact on engine performance.
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 manufacturing efficiency, maintains cooling performance, and ensures uniform airflow through the blade, preventing residual core material and minimizing airflow reduction, thus optimizing both manufacturing and operational efficiency.
Implementation Method 1
Cooling air is typically bled from a compressor of the gas turbine engine... the internal cooling structure is designed for optimal cooling efficiency
Implementation Method 2
The cooling structures furthermore comprise a multitude of trip strips arranged on the walls of the longitudinal passages, all of which oriented at approximately 45° to the direction of flow through the passage
Implementation Method 3
Following the molding process, the ceramic core is removed from the blade by a leaching process
Data Source
Figure 1
Figure 2
Figure 3a~3d
AI summary
A gas turbine rotating blade (1) comprises an internal cooling structure having at least three cooling air passages (5-7) in fluid connection with one another by means of turns (9, 10). An opening (12) provides an outlet for dissolved core material to be removed from the blade following casting of the cooling structure without any residue remaining within. According to the invention, the cooling structure comprises trip strips (13, 15) in the first and second passage (5, 6) with specified ratio of height to distance between trip strips and the trip strips (13) in the first passage being arranged at 90° with respect to the direction of airflow. In a particular embodiment, the trip strips (15) in the second passage (6) are arranged at angle of 45°. The design according to the invention assures sufficient airflow through first and second air passages (5, 6).