Passive Cooling Air Modulation for Turbine Heat Transfer Control
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Solution Overview
Problem
Current turbomachine cooling systems lack efficient passive flow modulation to optimize cooling air distribution based on temperature changes, leading to suboptimal heat transfer efficiency and turbine performance across varying operating conditions.
Innovation Solution
The implementation of passive flow modulation devices with temperature-sensitive elements, such as thermally expandable materials and bimetallic arrangements, to control the flow of cooling air through orifices in turbomachines, allowing for variable and optimized cooling air distribution based on temperature and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If passive flow modulation devices with temperature-sensitive elements are implemented, then cooling flow efficiency and heat transfer are improved, but device complexity increases
Solution Approach 1:
The temperature-sensitive element automatically responds to temperature changes within the rotor space, opening or closing the valve without external control systems. This self-regulating mechanism provides adaptive cooling flow modulation while avoiding complex control electronics or additional actuators, thus improving energy efficiency without proportionally increasing device complexity
Solution Approach 2:
The valve flow characteristic is modified based on temperature conditions through the temperature-sensitive element. As temperature changes, the element alters the valve opening degree, dynamically adjusting the cooling air flow rate to match actual thermal conditions, thereby optimizing heat transfer efficiency across varying operating conditions
2Temperature
If cooling air flow is increased to improve heat transfer efficiency, then turbine component cooling is enhanced, but turbine output and efficiency decrease due to reduced available work
Solution Approach 1:
The cooling air flow rate is made dynamic rather than fixed, allowing it to adjust automatically according to turbine operating conditions. The temperature-sensitive element enables the valve to open or close based on real-time temperature changes, providing enhanced cooling only when thermally needed and maintaining higher turbine output during conditions where less cooling is required
Solution Approach 2:
The system dynamically changes the cooling air flow parameter in response to temperature variations. By modulating the valve opening degree based on thermal conditions, the system optimizes the balance between heat transfer efficiency and turbine power output, ensuring adequate cooling while maximizing available work across the operating range
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
These devices provide substantial cooling flow savings and improved turbine efficiency by adjusting cooling air flow according to temperature changes, enhancing heat transfer efficiency and output across the operating range of the turbine.
Implementation Method 1
temperature sensitive element disposed within the hot area and configured to open or close the valve in response to a change in temperature within the rotor space
Implementation Method 2
bimetallic element configured to actuate the orifice plate in response to a change in temperature of the cooling air
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A passive flow modulation device (36) according to an embodiment includes: a temperature sensitive element (54) disposed within a first area (30); a piston (60) coupled to the temperature sensitive element (54), the piston (60) extending through a wall to a second area (44), wherein the first area (30) is at a higher temperature than the second area (44); and a valve arrangement (42) disposed in the second area (44) and actuated by a distal end portion of the piston (60), the valve arrangement (42) tangentially injecting a supply of cooling air (32) through an angled orifice (34) from the second area (44) into the first area (30) in response an increase in temperature in the first area (44). A passive flow modulation device (38) according to another embodiment comprises: a temperature sensitive element (78); a piston (86) coupled to the temperature sensitive element (78), the piston (86) including a head section (90), wherein the temperature sensitive element (78) and the piston (86) are disposed in a first area (30); and an orifice (34), extending from a second area into the first area (30), for supplying a flow of cooling air (32) from the second area to the first area (30), wherein the first area (30) is at a higher temperature than the second area; wherein the temperature sensitive element (78) enlarges or contracts to selectively position the head (90) of the piston (86) over a portion of the aperture (34) to control the flow of cooling air (32) from the second area into the first area (30). A corresponding turbine cooling system comprising a passive flow modulation device is also provided.