Measurement Method of Pulsation Micro Flow Based on Poiseuille Law

In order to solve the measurement problem of pulsating micro flow under high pressure conditions in the field of physical and chemical analysis instruments, based on Hagen-Poiseuille law, the differential pressure signal was used for indirect measurement combined with the characteristics of high pressure resistance and fast response of differential pressure transmitter. This study designed measurement scheme of differential pressure value in pulsation flow path. By means of numerical integration and time correction, the cumulative mass converted from differential pressure signals was compared with the cumulative mass of analytical balance to verify the measurement accuracy. The differential pressure method effectively solves the problem of low measurement accuracy of previous balance weighing and stopwatch timing method. Furthermore, the instantaneous flow rate converted from differential pressure signal was verified by the function of dynamic sampling of analytical balance. The results show that in the range of
$(0.2\sim 0.5)\text{mL}/\min$
, the error of mean flow rate of differential pressure method is not higher than
$\pm 0.5\%$
of read data, and the error of instantaneous flow rate is not higher than
$\pm 1.5\%$
of read data, which meets the requirements of related instruments on measuring accuracy. Meanwhile, it solves the problems of high price of micro flow sensor and limited pressure resistance value in the course of using.