为使大型水平管降膜多效蒸发海水淡化装置的横管降膜蒸发器均匀布液，自主设计并搭建了一套离心喷嘴喷淋特性实验台及径向喷淋密度测量装置，通过高速摄影仪拍摄的喷淋照片对喷淋外缘进行标注测量，得到喷嘴各喷淋锥角，对旋流式空心喷嘴的流量、喷淋锥角和径向喷淋密度等喷淋参数随入口压力、喷淋高度的变化规律进行实验探究分析。结果表明，流量随入口压力增加而增加，但入口压力越大，流量增长速度越缓慢；正常工况下，喷淋锥角由喷嘴出口扩张段角度决定，与喷嘴扩张角保持一致，在重力作用下出现向内的收缩圆弧液膜边；喷淋形状为规则的环形喷淋，入口压力增加使有效喷淋区域整体向中心压缩，喷淋密度峰值变大，两波峰的对称性得到改善，压力为349 kPa时，喷淋密度基本完全对称，增加喷淋高度则情况相反。根据此喷淋密度分布特点，在设计横管蒸发布液器时合理控制工况压强，根据峰谷叠加原理可有效消除无效喷淋区域。
In order to uniform distribution of liquid in the large horizontal-tube low temperature multi-effect distillation (MED) desalination, the spray characteristics of a hollow nozzle were studied experimentally. A centrifugal nozzle spray characteristic test-bed and a radial spray density measurement device were designed and built independently. The spray cone angles of the nozzles were obtained by marking the spray edge with the spray photographs taken by the high-speed camera. The variations of flow rate, spray cone angle and radial spray density versus spray pressure, as well as the radial spray density versus spray height were the main focus of the present work. The experimental results showed the export flow rate with the increase of inlet pressure, and the growth rate of flow rate tended to be slower. In normal experiment conditions, the spray cone angle was determined by the angle of the divergent section at the nozzle outlet, while it shrank the inner edge of the circular liquid film due to the loss of power under gravity, and the spray of the hollow nozzle exhibited a regular annular shape. As the inlet pressure increased, the effective spray area extended to the center as a whole, and the peak value of spray density also increased obviously, the symmetry of which was improved and the spray density was basically symmetrical when the pressure was 349 kPa. While increasing spray height had an opposite effect. With the increasing of spray height, the two peaks gradually moved away from the center and the radial droplet distribution was more uniform. The peak value of spray density decreased but always dominated, and the effective spray area expanded outwards. When designing the horizontal-tube evaporation distributor, the operating pressure should be controlled reasonably depending on the uniformity of nozzle spray density. The ineffective spray area can be eliminated effectively according to the principle of peak-valley superposition.
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