Prediction of Sand Transport and Deposition in a Two-Pass Internal Cooling Duct
Prediction of Sand Transport and Deposition in a Two-Pass Internal Cooling Duct
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二回程内冷管道中砂粒输送和沉积的预测
DOI：
10.1115/1.4032340
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
D. Tafti
中科院分区：
文献类型：
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作者：
Sukhjinderjit Singh;D. Tafti
研究了近发动机工况下双通道内冷肋形通道内的沙粒输运和沉积。大涡模拟（LES）计算进行体雷诺数为25,000计算流场和传热。采用定壁温边界条件研究了温度对颗粒沉积的影响。考虑950 °C、1000 °C和1050 °C三种不同的壁温。考虑5-25 μm范围内的颗粒尺寸。建立了一个新的沉积模型，该模型考虑了颗粒成分、温度、撞击速度和角度以及颗粒和表面的材料特性。计算的碰撞和沉积模式进行了讨论，为不同的暴露表面在两个通过的几何形状。除了前肋面，在弯曲区域和第二道次的第一个四分之一处观察到最高的颗粒碰撞和沉积。对于所考虑的所有三个壁温，在两次通过几何形状中观察到显著的沉积。除了弯曲区域的下游半部分之外，颗粒碰撞和沉积主要由较大的颗粒控制。总的来说，对于950 °C、1000 °C和1050 °C的三个壁温，在两次通过中分别约有38%、59%和67%的注入颗粒存款。虽然颗粒撞击对于950 °C的壁温是最高的，但是对于1000 °C和1050 °C的情况观察到更高的沉积。沉积随壁面温度的升高而显著增加。对于1000 °C，大约12%的撞击颗粒存款。对于1050 °C，大约23%的颗粒存款在冲击。对于所有这三种情况，由于较高的湍流和直接冲击，与第一次通过相比，第二次通过经历较高的沉积。
Sand transport and deposition is investigated in a two-pass internal cooling ribbed geometry at near engine conditions. Large-eddy simulation (LES) calculations are performed for bulk Reynolds number of 25,000 to calculate flow field and heat transfer. Constant wall temperature boundary condition is used to investigate the effect of temperature on particle deposition. Three different wall temperatures of 950 °C, 1000 °C, and 1050 °C are considered. Particle sizes in range 5–25 μm are considered. A new deposition model which accounts for particle composition, temperature, impact velocity and angle and material properties of particle and surface is developed and applied. Calculated impingement and deposition patterns are discussed for different exposed surfaces in the two pass geometry. Other than the leading rib faces, the highest particle impingement and deposition is observed in the bend region and first quarter of the second pass. Significant deposition is observed in the two pass geometry for all three wall temperatures considered. Particle impingement and hence deposition is dominated by larger particles except in the downstream half of the bend region. In total, approximately 38%, 59%, and 67% of the injected particles deposit in the two passes, for the three wall temperatures of 950 °C, 1000 °C, and 1050 °C, respectively. While particle impingement is highest for wall temperature of 950 °C, higher deposition is observed for 1000 °C and 1050 °C cases. Deposition increases significantly with wall temperature. For 1000 °C, roughly 12% of the impacting particles deposit. For 1050 °C, approximately 23% of the particles deposit on impact. For all the three cases, the second pass experiences higher deposition compared to the first pass due to higher turbulence and direct impingement.