基于光源拼接的大视场聚焦纹影技术初步研究

随着风洞试验技术的发展，模型尺寸不断增大，大视场流场显示技术显得日益重要。传统纹影等流场显示技术受光学元件尺寸的限制，流场显示视场难以超过Φ1.0m。在聚焦纹影技术基础上，提出使用可拼接的LED光源或其他光源替换菲涅耳透镜，流场显示视场很容易超过Φ1.5m。在解决光源均匀照明、散热等问题后建立了一套视场为Φ150mm的原理性装置，清晰获得了蜡烛火焰及热吹风流场聚焦纹影图像。同时，可以在此类聚焦纹影系统中放置多套聚焦透镜，实现更大测试视场或不同截面的流场显示；在大视场流场显示中，需要在光源之后增加聚光镜等以提高光源利用效率。

Primary study of large-field focusing schlieren technique based on tiled light sources

With the development of wind tunnel test techniques, the size of the model is increasing, and the large-field flow visualization is becoming more and more important. Traditional schlieren and other flow visualization techniques are limited by the size of optical elements, and the field of view is difficult to exceed 1.0 meter. On the basis of the focusing schlieren technique, the Fresnel lens are replaced by the tiled LED light sources or other light sources, and the field of view can easily exceed 1.5 meter. After solving the problem of uniform illumination and heat dissipation of light sources, a principle device with 150mm field of view is set up, and the focusing schlieren images of the candle flame and the hot air flow field are clearly obtained. At the same time, multiple focusing lenses can be placed in this type of focusing schlieren system to show larger field of view or different sections. For the large field of view, it is necessary to increase the utilization efficiency of the light sources by the method of, for example, adding convergent lens at the rear end of the light source.