12 December 2016 7 9K Report

Hello

I'm trying to make a simulink model for Venturi tube, for the purpose of measuring volumetric airflow by making a pressure difference with a fan.

The paper "Model-based analysis and simulation of airflow control systems of ventilation units in building environments" written by "Wu, Zhuang; Melnik, Roderick V.N.; Borup, Finn" shows some relations about this topic, and I have collected these relations (from the original attached PDF paper) in the attached image (equations 1 to 9).

Question1: when we combine equation (9) with (8), we will get an equation with no relation between ΔPfan,rise (Pressure difference made by the fan) and fan tip speed, in other words, I need an equation that links ΔPfan,rise with fan tip speed (or fan RPM).

Question2: equation (20) shows the the dynamic model for the pressure sensor as follows:

ΔPout =1/τ(ΔPin -ΔPout)dt

is there any simple explanation?

Thanks in advance.

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