Effect of pressure fluctuation on droplet size distribution from pulse width modulated nozzles

Authors: WEI, ZHIMING - Shandong Academy Of Agricultural Sciences; Zhu, Heping; SALCEDO, RAMON - The Ohio State University; ZHANG, ZHIHONG - Kunming University Of Science And Technology

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2020
Publication Date: 7/12/2020
Citation: Wei, Z., Zhu, H., Salcedo, R., Zhang, Z. 2020. Effect of pressure fluctuation on droplet size distribution from pulse width modulated nozzles. In:Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE), July 13-15, 2020, Virtual Meeting. ASABE Paper No. 2000124.

Interpretive Summary:

Technical Abstract: Precision pesticide spray applications have been achieved with nozzles coupled with pulse width modulated (PWM) solenoid valves in recent years. However, PWM-controlled nozzles may produce inconsistent droplet size distributions and unstable pressures. Experiments were conducted with ten duty cycles ranging from 10% to 100% at an interval of 10%, and six standard flat fan nozzles (XR8001, XR8002, XR8003, XR8004, XR8005, XR8006) under conditions with and without nozzle operating pressure adjustments to measure droplet size distributions and operating pressures. Under the no-pressure-adjustment condition, the nozzle operating pressure was not adjusted as the duty cycle was changed. Under the pressure-adjustment condition, the nozzle operating pressure was adjusted to maintain at 276 kPa at all duty cycles. Test results showed that under the no-pressure-adjustment condition, nozzle operating pressures increased as duty cycle decreased from 90% to 10%, and the increase magnitudes depended on the nozzle orifice sizes. These pressure increases slightly reduced the droplet sizes.