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1. New breakthrough in flow measurement: Detailed explanation of embedded low-temperature Venturi flowmeter design - mastering core technology The embedded low-temperature Venturi flowmeter integrates pressure/temperature sensors and digital signal processing technology to achieve high-precision real-time measurement of fluid flow in low-temperature environments, solving the problems of large errors and slow response of conventional equipment in low-temperature conditions. It is suitable for low-temperature media such as liquid nitrogen and liquid oxygen, and has significant application value in industrial automation, energy metering, and other fields.
1. Design Background and Significance Low temperature fluids (such as liquid nitrogen and liquid oxygen) are widely used in chemical production, aerospace, scientific research experiments, and other fields. Accurate measurement of their flow rate is crucial for process control, energy metering, and safe operation.
. The habitual Venturi flowmeter has the following problems in low-temperature environments: material shrinkage: low temperature causes deformation of the metal throat and unstable throttling effect. Sensor failure: If the normal pressure/temperature is not adjusted properly, the sensitivity of the sensor will decrease or be damaged at low temperatures. Changes in fluid properties: sudden changes in density and viscosity of low-temperature media, affecting the flow differential pressure relationship. The embedded low-temperature Venturi flowmeter breaks through the limitations of conventional equipment by optimizing material selection, sensor design, and signal processing algorithms, providing a reliable solution for low-temperature flow measurement
2. Working principle and key technologies 1 The foundation of fluid dynamics is based on Bernoullis equation and continuity equation. When the fluid passes through the Venturi throat, the velocity changes as the throat cross-sectional area decreases and the flow velocity increases. Pressure change: static pressure decreases, dynamic pressure increases, and differential pressure is proportional to the square of flow velocity. Flow calculation: By measuring the differential pressure (Δ P) between the inlet and throat, combined with the fluid density (ρ) and throat diameter (d), the volumetric flow rate is calculated as follows: $$Q=C_d cdot A cdot sqrt {frac {2Delta P} {rho (1- (d/D) ^ 4)} $, where $C_d $is the flow coefficient, $A $is the throat cross-sectional area, and $D $is the inlet diameter
Used to correct density and volume expansion coefficient. Signal processing unit: microcontroller (MCU): ARM Cortex-M7 core is selected, integrated with floating-point arithmetic unit (FPU), to achieve high-speed data acquisition and processing. Digital Signal Processing (DSP): Filter out noise through Fast Fourier Transform (FFT) to improve the signal-to-noise ratio of differential pressure signals. Compensation algorithm: Temperature compensation: dynamically adjust the density value based on the fluid temperature to eliminate the effects of thermal expansion and contraction. Pressure compensation: Adjust the differential pressure measurement value based on static pressure data to adapt to different working conditions. Material selection for low-temperature adaptability design: Nickel based a