Sharma Deepak, Ghosh Durga Prasad, Dennis Sandra Jean, Abbasi Bahman
Oregon State University, Corvallis, OR 97331, USA.
Oregon State University, Cascades, OR 97702, USA.
Water Res. 2022 Aug 1;221:118726. doi: 10.1016/j.watres.2022.118726. Epub 2022 Jun 7.
A detailed experimental study is presented on fouling behavior of the anti-clogging perforated plate atomizer designed for high salinity applications, and compared with a conventional (plain-jet) airblast atomizer. Low-pressure regions around fast moving air in the outer layer of spray (as in conventional atomizers: plain-jet and prefilming) due to Venturi suction were identified as the root cause of atomizer clogging, as they facilitate salt accumulation on the atomizer surface from spray. Accordingly, severe atomizer fouling, and fluctuations in spray cone angle were observed in the conventional airblast atomizer over 2 h at 100°C air and 50°C saline (44° to 76° at 35,000 ppm, and 44° to 91° at 100,000 ppm). In this regard, the perforated plate atomizer provides a novel liquid-film airblast atomization by maintaining a liquid-annulus film (around the air outlet) as the outer layer of spray. Doing so we achieved nearly complete suppression of fouling, and spray cone angle fluctuations (28° ± 1° at 35,000 ppm, and 30° ± 1° at 100,000 ppm). Later, novel liquid-film atomization was adopted in the conventional airblast atomizer. While, the conventional airblast atomization needed atomizer cleaning/maintenance after 35 min for 175°C air and 65°C saline at 100,000 ppm, the liquid-film atomization showed no sign of fouling over 14 h. Hence, current work establishes a benchmark liquid-film airblast atomization mechanism in the anti-clogging perforated plate atomizer for complete suppression of fouling in airblast atomization. This extends the application of airblast atomizers from high evaporation jet engines to ZLD-HDH desalination systems, spraying, powder metallurgy, pharmaceuticals and hospitals, and spray drying and cooling.
本文对一种专为高盐度应用设计的防堵塞多孔板雾化器的结垢行为进行了详细的实验研究，并与传统的（平射流）鼓风式雾化器进行了比较。由于文丘里吸力，喷雾外层快速流动的空气周围的低压区域（如在传统雾化器：平射流和预成膜雾化器中）被确定为雾化器堵塞的根本原因，因为它们促进了盐分从喷雾中积聚在雾化器表面。因此，在100°C空气和50°C盐水条件下，传统鼓风式雾化器在2小时内出现了严重的雾化器结垢以及喷雾锥角波动（在35,000 ppm时为44°至76°，在100,000 ppm时为44°至91°）。在这方面，多孔板雾化器通过在空气出口周围保持液环膜作为喷雾外层，提供了一种新型的液膜鼓风雾化。这样做，我们几乎完全抑制了结垢和喷雾锥角波动（在35,000 ppm时为28°±1°，在100,000 ppm时为30°±1°）。后来，传统鼓风式雾化器采用了新型液膜雾化。虽然在100,000 ppm的175°C空气和65°C盐水条件下，传统鼓风雾化在35分钟后需要对雾化器进行清洁/维护，但液膜雾化在14小时内没有结垢迹象。因此，当前的工作在防堵塞多孔板雾化器中建立了一种基准液膜鼓风雾化机制，以完全抑制鼓风雾化中的结垢。这将鼓风式雾化器的应用范围从高蒸发喷气发动机扩展到零排放-热法脱盐系统、喷涂、粉末冶金、制药和医院以及喷雾干燥和冷却。
