Thermal Valve Deflector for Gas Turbine Cooling Reliability
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Solution Overview
Problem
Thermal valves in gas turbine fluid systems experience premature wear due to excessive open/close cycling caused by temperature oscillations around the threshold temperature range, leading to unnecessary valve cycling and reduced mean time between failures.
Innovation Solution
Incorporating a deflector in the cooling system to either deflect cooled liquid flow away from the temperature sensing element or mix hot bypass flow with cooled flow from the heat exchanger, reducing direct impingement and exposure to temperature fluctuations, thereby minimizing unnecessary valve activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermal valve is positioned to sense temperature downstream of the heat exchanger and bypass conduit, then it can effectively control the bypass flow, but it experiences excessive open/close cycling due to temperature oscillations around the threshold temperature range
Solution Approach 1:
A deflector is introduced as an intermediary component between the heat exchanger outlet and the thermal valve's temperature sensing element. The deflector redirects the cooled liquid flow to bypass the sensing element, preventing direct impingement of temperature fluctuations on the valve mechanism while maintaining the valve's ability to sense overall temperature changes for control purposes.
Solution Approach 2:
The system separates the temperature sensing function from the direct flow path. The deflector creates a spatial segmentation where the main cooled flow is directed away from the sensing element, while the sensing element remains exposed to the thermal environment sufficient for temperature detection but protected from direct flow-induced oscillations.
2Speed
If the temperature sensing element is exposed to direct cooled liquid flow from the heat exchanger outlet, then it responds quickly to temperature changes, but it causes unnecessary valve cycling when temperature oscillates around the threshold
Solution Approach 1:
The deflector acts as a mediator that modifies the interaction between cooled liquid flow and the temperature sensing element. It allows thermal energy transfer to continue for temperature sensing while blocking the mechanical impingement of direct flow that causes oscillatory behavior and unnecessary cycling.
Solution Approach 2:
The deflector creates a localized modification in the flow field around the temperature sensing element. The flow characteristics are changed locally at the sensing element position to reduce direct impingement, while maintaining overall system temperature sensing capability through exposure to the thermal environment.
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
The deflector strategy reduces unnecessary cycling of the thermal valve, increasing the mean time between failures by stabilizing the temperature sensing element's exposure, thus preventing premature wear and improving the valve's operational reliability.
Implementation Method 1
the temperature sensing element configured to selectively move the thermal valve in response to a temperature change of the liquid which the temperature sensing element is exposed to
Implementation Method 2
a deflector positioned between the temperature sensing element and the heat exchanger outlet, the deflector being shaped and configured to impede directed impingement of cooled liquid flow exiting the heat exchanger outlet on the temperature sensing element
Implementation Method 3
the valve having a temperature sensing element positioned downstream of both the heat exchanger and the bypass conduit, the temperature sensing element configured to selectively move the thermal valve in response to a temperature change of the liquid
Data Source
AI summary
The liquid cooling system has a heat exchanger having a fluid inlet and an outlet; a fluid supply conduit leading to the inlet of the heat exchanger; a fluid return conduit extending from the outlet of the heat exchanger; a bypass conduit extending between the fluid supply conduit and the fluid return conduit; a thermal valve configured for selectively closing the bypass conduit, the valve having a temperature sensing element positioned downstream of both the heat exchanger and the bypass conduit, the temperature sensing element configured to selectively move the thermal valve in response to a temperature change of the liquid which the temperature sensing element is exposed to relative to a temperature threshold of the valve; and a deflector positioned between the temperature sensing element and at least one of the bypass conduit and the heat exchanger outlet.