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以冲击旋流强化换热为研究背景,通过粒子示踪的流场显示技术,对受限空间内斜向冲击凹柱面的流场结构开展了试验研究.通过改变冲击雷诺数、冲击角度、相对冲击间距(冲击间距和冲击孔直径之比)以及相对曲率(冲击孔直径同凹面靶板直径之比)等参数,分析了受限空间中,斜向冲击曲率表面后产生的涡系结构及其发展和变化规律.流场显现结果表明:随冲击雷诺数的增加,在冲击滞止区域两侧都能形成稳定的旋流结构,并且在受限空间的角部,进一步形成了诱导涡.试验中发现随着冲击雷诺数的增加,冲击气流与壁面分离处对应的圆心角增大,分离推迟;随着相对冲击间距值的增加,气流与壁面分离处对应的圆心角越来越大,相对于受限空间的大小,诱导涡的范围越来越小.由于冲击角度的影响,冲击射流在滞止区域左侧射流(相对冲击角度较小)与壁面分离比在右侧(相对冲击角度较大)提前,同时更容易产生旋流.
In this paper, the impinging swirling heat transfer enhancement is the research background, and the flow field structure of oblique impact cylindrical cavity in confined space is experimentally studied by the flow field display technology of particle tracer.By changing the impact Reynolds number, impact angle, The relationship between relative impact distance (the ratio of impact distance to impact hole diameter) and relative curvature (the ratio of impact hole diameter to the diameter of concave target) and other parameters were analyzed. The results show that with the increase of impact Reynolds number, a stable swirling structure can be formed on both sides of the impacted hysteresis region, and the induced vortices are further formed at the corner of the confined space. It is found that with the increase of impact Reynolds number, the corresponding central angle of impact airflow and wall separation increases, and the separation is delayed. With the increase of relative impact spacing, the corresponding central angle of air flow and wall separation increases, Relative to the size of the confined space, the induced vorticity range is getting smaller and smaller.As a result of the impact angle, the impinging jets on the left side of the stagnant region jet (relative impact angle is smaller) than the wall separation ratio on the right The impact angle is large) in advance, and are more likely to swirl.