Turbine Blade Tip Cooling Plenum to Prevent Hot Gas Backflow
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Solution Overview
Problem
Existing turbine blade tip cooling configurations suffer from inadequate cooling, particularly near the trailing edge, and can experience backflow of hot combustion gases, leading to thermal degradation and oxidation.
Innovation Solution
A turbine blade design featuring a serpentine interior cooling passage with multiple legs and junctions, tip cooling apertures, and a plenum to enhance cooling efficiency, along with strategically positioned tip cooling apertures to prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing tip cooling configurations are used, then the blade tip cooling is provided, but inadequate cooling occurs near the trailing edge and backflow of hot combustion gas occurs
Solution Approach 1:
The tip cooling system is segmented into multiple independent cooling circuits: a first tip cooling circuit with cooling holes on the pressure side, and a second tip cooling circuit with cooling holes on the suction side. This segmentation allows independent optimization of cooling flow to each surface, ensuring adequate cooling coverage across the entire blade tip including the trailing edge region.
Solution Approach 2:
Different cooling strategies are applied to different regions of the blade tip. The pressure side receives cooling through the first circuit with specific hole positioning, while the suction side receives cooling through the second circuit. This local differentiation ensures that each region receives appropriate cooling flow tailored to its thermal conditions, preventing hot gas backflow in critical areas.
2Quantity of substance
If existing tip cooling configurations are used, then cooling air flow is provided to the blade tip, but backflow of hot combustion gas occurs into the turbine blade
Solution Approach 1:
Cooling holes are strategically positioned and oriented to create cooling flow that opposes the potential backflow of hot combustion gas before it can penetrate into the blade tip. The cooling air is delivered in advance to critical regions, creating a protective flow barrier that prevents hot gas intrusion.
Solution Approach 2:
The dual-circuit cooling system provides feedback control of cooling flow distribution. By independently managing the first circuit (pressure side) and second circuit (suction side), the system can respond to varying thermal conditions and maintain effective cooling flow that prevents hot gas backflow under different operating conditions.
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
Improves cooling efficiency and reduces thermal degradation by ensuring adequate airflow to the blade tip, minimizing backflow of hot gases and enhancing the operational durability of turbine blades.
Implementation Method 1
The first leg is configured to receive pressurized gas from at least one supply channel of the plurality of supply channels
Implementation Method 2
The plurality of tip cooling apertures includes a forward tip cooling aperture that has a forward end that opens into the first junction portion and an aftward end that opens through the pressure side surface of the blade tip
Implementation Method 3
The first junction portion includes a plenum that overlaps the third leg in an axial direction of the turbine blade, wherein the forward end of the forward tip cooling aperture opens into the plenum
Implementation Method 4
providing cooling air flow to the turbine blade tip can improve the operational durability of the turbine blade
Data Source
AI summary
A turbine blade includes a root, tip, and airfoil. The turbine blade defines a serpentine interior passage having first through third legs, and first and second junctions. The first leg receives pressurized gas from a supply channel of the root. The first leg extends radially and the first junction connects it to the second leg proximate the tip. The second leg extends radially between the first and second junctions. The second junction connects the second and third legs. The third leg extends radially toward the tip. The tip defines cooling apertures open through a pressure side thereof. The cooling apertures include a forward aperture with a forward end opening into the first junction and an aftward end opening through the pressure side surface of the tip at a location that is radially outward of the third leg and axially aftward of at least a portion of the third leg.