Experimental investigation of flat fan nozzle V-cut depths and its impact on spray characteristics

Abstract

Abstract In this study, five locally produced different V-cut flat fan nozzles named A2, B2, C2, D2 and E2 were introduced for experimental investigation on their effect on spray characteristics. The results were collected about droplet size, spray volume distribution, spray angle, sheet length, velocity, Weber number and discharge coefficient experimentally at pressures of 100 kPa, 200 kPa, 300 kPa and 400 kPa respectively. To evaluate nozzle performance under varying pressures, each parameter had its own experimental setup. The results showed that V-cut depth greatly impacts flat fan nozzle performance. Spray angle and droplet size were both enhanced with increasing V-cut depth. The deeper cuts improved the flow dynamics, which in turn permitted the nozzle to spray at a wider angle and with finer droplets. This study reveals that as increasing the spray angle significantly improved the spray volume distribution respectively. This allows for more uniform and wide coverage. Conversely, reducing the depth of the V-cut increases the stream velocity resulted the droplets become coarser due to insufficient shear stress. When the fluid’s velocity increases too rapidly, the shear stress does not have adequate time to effectively atomize the fluid into fine droplets. While higher velocity generally enhances shear, excessive flow speed can hinder the fluid from experiencing the appropriate shear forces at the optimal moment. As a result, instead of producing smaller droplets, the fluid ends up generating larger, coarser droplets. A mathematical model was developed from the experimental data to estimate droplet size and spray angle. The model’s predictions closely match the experimental results, demonstrating the model’s accuracy. The investigation found that the optimum V-shaped cutting depths were C2, D2, and E2, as these nozzles obtained better spray angles and showed a greatly improvement droplet size and spray volume distribution.