Numerical Modeling of Diaphragm Dosing Pumps with Fluid-Structure Interaction Analysis

In this paper, the performance of a diaphragm dosing pump of the injection odorizers is simulated with the fluid-structure interaction analysis. The simulation results are validated with experimental data and the largest relative error is 16% for the average flow rate. Performance simulation of the diaphragm pump for the diaphragm oscillation period of 1 second and three different diaphragm displacement amplitudes of 0.8, 0.5, and 0.2 mm, shows that as the amplitude increases, the fluid velocity and consequently the flow rate of the pump increases. The average flow rate of the pump in the mentioned amplitudes is equal to 0.002, 0.0013, and 0.0005 kg/s, respectively. As the amplitude increases from 0.2 to 0.8 mm, the maximum stress applied to the diaphragm increases from 32.2 to 99.2 MPa (equivalent to 208%). Also, the effect of diaphragm oscillation frequency on pump performance is investigated. The results show that the pump's flow rate directly and linearly relates to the diaphragm oscillation frequency. In contrast, the applied stress on the diaphragm is not frequency-dependent and in the same ratios of the period, the applied stress is almost constant. According to the results, if the pump amplitude is set to 0.5 mm and the frequency is 1.6 Hz, instead of operating at a diaphragm amplitude of 0.8 mm and a frequency of 1 Hz, the pump's flow rate will be the same. While the maximum amount of stress in the diaphragm will be reduced by about 30% and the probability of damage will be reduced.