# A High-Performance Piezoelectric Micropump with Multi-Chamber in Series
## 5 Results and Analysis
### Output Performance Test of Multi-Chamber Series Piezoelectric Micropump  
Figure 8 shows the relationship between the limit output performance and frequency of the multi-chamber series piezoelectric micropump under 100 V. It is evident that the limit output performance of the dual-chamber micropump and the four-chamber micropump show a trend of first increasing and then decreasing with the increase of frequency, while the optimal operating frequency of the dual-chamber micropump is lower than that of the four-chamber micropump. This is because the response characteristics of the piezoelectric micropump under working conditions have changed, thus affecting the outflow efficiency of the inlet and outlet of the micropump. For a dual-chamber series piezoelectric micropump, when the frequency is 120 Hz, the limit output flow is 37 mL/min; when the frequency is 100 Hz, the limit output pressure is 43.7 kPa. For a four-chamber series piezoelectric micropump, when the frequency is 450 Hz, the limit output flow rate reaches 62.5 mL/min; when the frequency is 550 Hz, the optimal output pressure exceeds 100 kPa.  
Figure 7: Output performance of micropump with different chamber heights.  
Figure 9 provides the relationship between the limit output performance of the multi-chamber series piezoelectric micropump and the voltage. It is evident that when the frequency is constant, the limit output performance of the multi-chamber series piezoelectric micropump increases with the increase in the voltage and has a good linear relationship. For the dual-chamber series piezoelectric micropump, when the voltage is constant at 170 V, the output flow rate is 65.5 mL/min at 120 Hz, and the output pressure can reach 59.1 kPa at 100 Hz. For the four-chamber series piezoelectric micropump, when the voltage is constant at 170 V, the output flow reaches 110 mL/min at 450 Hz, and the output pressure can reach 142 kPa at 550 Hz. Under the same voltage, the output flow rate of the four-chamber series micropump is about 1.6 times that of the double-chamber series micropump, and the output pressure is about 2.4 times that of double-chamber series one.  
Next, Table 2 provides the output performance of single-, dual-, and four-chamber micropumps under 100 V. The output flow rate of the four-chamber micropump is about 1.69 times that of the double-chamber micropump and 2.97 times that of the single-chamber micropump; its output pressure is about 2.39 times of double-chamber micropump and 4.5 times of the single-chamber micropump. The output flow rate of the double-chamber  
Figure 8: The relationship between the output performance of the multi-chamber series micropump vs. the frequency and voltage. (**a**) The relationship between flow rate and frequency at 100 V. (**b**) The relationship between pressure and frequency at 100 V.  
Figure 9: The relationship between the output performance of the multi-chamber series micropump and the frequency and voltage. (**a**) The relationship between flow rate and voltage. (**b**) The relationship between pressure and voltage.  
micropump is about 1.73 times that of the single-chamber micropump, and the output pressure is about 1.88 times that of the single-chamber micropump.  
Furthermore, Table 3 shows a comparison of the technical reports of piezoelectric micropumps. It is evident that the piezoelectric micropumps reported in these studies are lacking in output performance or overall size. The piezoelectric micropump proposed in this work makes up for the deficiency to the maximum extent, i.e., both high output performance and miniaturization. Therefore, this work promotes the development of piezoelectric micropumps with high output performance.