Thermal Sensor Gas Parameter Determination Without Pressure Drop
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Solution Overview
Problem
Existing methods for determining gas parameters such as the Prandtl number, hydrogen concentration, or combustion parameters are inaccurate and often require significant pressure drops or complex setups, limiting their efficiency and cost-effectiveness.
Innovation Solution
A thermal sensor device with at least one temperature sensor and a heater element is used to measure temperature, heat-transfer, and heat-capacity related parameters, along with a natural-convection parameter, allowing for the calculation of gas parameters like the Prandtl number and hydrogen concentration without the need for significant pressure drops or complex flow conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sonic nozzle is used to determine combustion parameter, then measurement capability is improved, but pressure drop increases significantly
Solution Approach 1:
The patent extracts the measurement function from the flow conditioning element. Instead of using a sonic nozzle that creates pressure drop to enable measurement, the invention uses a separate flow straightener that merely conditions the flow, while the measurement is performed by thermal sensors that do not disturb the flow. This separates the flow conditioning function from the measurement function, eliminating the need for pressure drop.
Solution Approach 2:
The patent introduces thermal conductivity as an intermediary property for measurement. Rather than measuring flow parameters directly (which would require flow disturbance), the invention measures thermal conductivity of the gas, which is affected by combustion parameters but can be measured without disturbing the flow. The thermal sensors act as intermediaries that couple the flow field to the measurement system without causing pressure drop.
2Device complexity
If empirical correlation methods are used for gas parameter determination, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent makes the thermal sensors serve multiple functions. The same thermal conductivity sensors are used to determine both the thermal properties of the gas and, through correlation functions, the combustion parameters. This multi-functionality allows accurate measurement without requiring separate complex measurement systems for each parameter, thus maintaining low device complexity while improving precision.
Solution Approach 2:
The patent changes the measurement parameter from direct flow/combustion parameters to thermal conductivity. By measuring thermal conductivity (a fundamental property that can be measured accurately with simple thermal sensors) and then correlating it to combustion parameters, the invention achieves high measurement precision with simple devices. The correlation functions transform the thermal conductivity data into meaningful combustion parameters.
3Device complexity
If thermal sensors are used without flow conditioning, then device complexity is reduced, but measurement precision deteriorates due to flow disturbances
Solution Approach 1:
The patent segments the measurement system into separate functional zones. The flow straightener is placed upstream to condition the flow, while the thermal sensors are positioned in a separate measurement zone where the flow is already conditioned. This spatial segmentation allows the flow conditioning and measurement functions to be performed independently, ensuring accurate thermal measurements without requiring the sensors themselves to create flow disturbances.
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 approach enables accurate and cost-efficient determination of gas parameters in real-time, eliminating the need for pressure drops and complex setups, resulting in a compact and efficient device capable of online measurements.
Implementation Method 1
a heat-transfer parameter of the gas is determined from a stationary temperature distribution in the gas caused by the heater element
Implementation Method 2
a natural-convection parameter of the gas is determined from a convection pattern in the gas caused by action of the heater element
Implementation Method 3
A first temperature sensor, a second temperature sensor, and a heater element therebetween are provided on the measurement tube. A temperature difference between the temperature sensors is monitored
Data Source
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AI summary
A method for determining a gas parameter (Pr;CH;Hρ; Iw; NM) of a gas (g), said method comprising (i) operating a thermal sensor device (1); (ii) calculating from an output of said thermal sensor device (1), a temperature (T), a heat-transfer parameter (λ), a heat-capacity related parameter (D; cpρ), and a natural-convection parameter 1vD of said gas (g); and (iii) calculating said gas parameter (Pr;CH;Hρ; Iw; NM) from said heat-transfer parameter (λ), said heat-capacity related parameter (D; cpρ), and said natural-convection parameter 1vD.