Turbine Blade Film Cooling Offset Ducts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing design of gas turbine blades faces challenges in achieving uniform and effective cooling of the leading edge region while minimizing coolant air requirements, due to abrupt changes in outlet duct orientation and access restrictions during production, leading to inefficiencies and increased compressor mass flow losses.
Innovation Solution
The outlet ducts' transitional points are offset relative to each other in the longitudinal direction, creating a homogeneous distribution of outlet ducts across the leading edge, maintaining an oblique orientation for effective film cooling and reducing coolant consumption by avoiding direct gaps between adjacent rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outlet ducts are oriented obliquely with respect to the longitudinal direction of the turbine blade, then film cooling effectiveness is improved, but manufacturing complexity increases due to abrupt orientation changes at transitional points
Solution Approach 1:
The outlet ducts are divided into multiple sections along their length, with each section having a different orientation angle. This segmentation allows the ducts to gradually change direction from the coolant duct to the leading edge, avoiding abrupt orientation changes while maintaining effective film cooling.
Solution Approach 2:
The outlet ducts employ a dynamic orientation profile where the angle of inclination varies continuously along the duct length rather than remaining fixed. This dynamic configuration optimizes the cooling air flow direction at different positions, improving film cooling effectiveness without requiring complex abrupt transitions.
2Reliability
If outlet ducts are drilled obliquely from the leading edge region, then film cooling performance is improved, but access for drilling instruments is obstructed by platforms
Solution Approach 1:
Instead of drilling outlet ducts from the leading edge region outward, the drilling is performed in reverse direction - from the coolant duct location toward the leading edge. This inversion of the drilling direction allows access from the platform side where instruments can reach, while still creating properly oriented outlet ducts for effective film cooling.
Solution Approach 2:
The coolant duct serves as an intermediary access point for creating the outlet ducts. By drilling through the coolant duct wall rather than directly from the leading edge, the process bypasses the obstruction caused by platforms while maintaining the desired oblique orientation of outlet ducts for optimal film cooling performance.
3Temperature
If coolant ducts are provided in the blade leaf, then convective cooling is achieved, but coolant air requirements increase
Solution Approach 1:
The cooling system employs local quality optimization by providing convective cooling through coolant ducts in specific high-temperature regions of the blade, particularly near the leading edge, rather than uniform cooling throughout. This targeted approach reduces overall coolant air requirements while maintaining effective temperature control where most needed.
Solution Approach 2:
The invention merges convective cooling and film cooling functions into a single integrated system. The coolant ducts provide convective cooling internally, while the same coolant flow is directed through outlet ducts to form a protective film on the blade surface. This combination achieves comprehensive cooling with reduced coolant air consumption compared to separate systems.
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 arrangement ensures reliable and uniform cooling of the blade surface and interior, reducing material stress and coolant air requirements, thereby enhancing the efficiency of the gas turbine by optimizing film cooling and convective cooling without excessive coolant usage.
Implementation Method 1
the cooling air, after flowing through the turbine blade, emerges from the outlet ports, also designated as film cooling holes, and forms a cooling air film on the surface of the blade leaf. This cooling air film largely protects the material on the surface against direct and over intensive contact with the hot working medium flowing past at high velocity.
Implementation Method 2
The cooling air, emanating from these coolant ducts, flows, in outlet ducts branching off from the latter, to the regions of the turbine blade which are in each case provided, with the result that a convective cooling of the blade interior and of the blade wall is achieved.
Data Source
AI summary
A turbine blade (2), with a root section (4), with a tip section (6) and with a blade leaf (12) which is provided with a number of coolant ducts (22) through which a coolant (K) is capable of flowing, outlet ducts (34) which issue in outlet ports (24) branching off, in the leading edge region (28) of the blade leaf (12), from a coolant duct (22) running essentially in the longitudinal direction (L) of the turbine blade (2) and spaced apart from the leading edge (14), the outlet ports (24) being arranged along at least two rows oriented essentially parallel to the leading edge (14), and the outlet ducts (34) being oriented, in the region of their respective outlet port (24), obliquely with respect to the longitudinal direction (L) of the turbine blade (2), in such a way that the coolant (K) flowing out in a root-side subsection (38) of each row possesses, in the region of the outlet ports (24), a velocity component pointing toward the tip section (6) of the turbine blade (2), and the coolant (K) flowing out in a tip-side subsection (42), continguous thereto, of each row has a velocity component pointing toward the root section (4), is designed for a particularly reliable and uniform cooling of the leading edge region (28), at the same time with the requirement for coolant (K) being kept particularly low. For this purpose, according to the invention, the transitional points (40) at which the orientation of the outlet ducts (34) changes are arranged so as to be offset relative to one another in the longitudinal direction (L) in each case for two adjacent rows.