肋片结构的冲击强化换热特性研究

Study on Flow and Heat Transfer Characteristics of “impingement-rib”Composite Structure

通过三维数值模拟的方法研究了肋片结构的冲击强化换热特性,分别分析了射流孔排布方式(顺排、长菱形和正菱形),变肋片结构(方形肋、三角肋和梯形肋),射流冲击雷诺数(Re=6 000~30 000)等参数的影响,研究结果表明:当射流孔长菱形排布时,靶板表面上射流冲击驻点区Nu最高,在肋片周围能形成明显的涡流且肋结构为三角形时涡量尺度大,主要出现在肋片附近;此外,靶面上冲击换热面积较大且相对均匀,即不会出现局部区域内对流换热差的情况;当射流孔为正菱形布置,射流冲击驻点区Nu较长菱形排布时更大,但对于靶面射流冲击换热不均匀;总的来说,射流冲击孔排布宜选择长菱形排布且肋片结构选三角肋,可以较明显地改善冲击靶板上的对流换热能力。

Three-dimensional simulation was used to study the heat transfer characteristics of the stiffened ribs structure. Parameters of impinging hole arrays（ inline array,rhomboid array,rhombus array）,rib pro-files（ rectangular,triangle,trapezoid）,jet impingement Reynolds number（ Re =6 000 ~ 30 000） were analyzed. The results show that： when the jet holes are arranged as a long diamond,the Nusselt number reaches to the highest at the stagnation area,there are apparent vortexes around the ribs and the vortex value reaches to the maximum around the triangle ribs. Besides,there is some area with bigger heat transfer coefficient on the target plate. Rhomboidal arrangement for impingement holes is better than the rhombic arrangement for at the stagnation area,but don＇t get a uniform temperature arrangement on the target plate. To sum up,rhomboidal array of the impingement holes with triangle ribs are important parameters for the heat transfer on the target.