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首页> 外文期刊>International Journal of Heat and Mass Transfer >Effect of micro rib on aerothermal dynamic in channel flow
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Effect of micro rib on aerothermal dynamic in channel flow

机译：微肋对通道流动空气动力的影响

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In the present development of gas turbine, there is a main contradiction between the limited amount of cold air, the pressure head in the gas supply system and the large flow loss caused by the cooling unit inside the turbine blade. It leads to demands for the cooling techniques to provide efficient heat transfer with lower pressure loss. Surface micro turbulator is considered as a potential cooling technique. In this study, numerical simulation and experimental research were undertaken to evaluate the turbulent flow heat transfer and pressure loss in channel with a typical 2-D micro rib on one wall with different rib heights. Investigated rib heights range from 0.0013～0.053 of the channel hydraulic diameter ratio(h/D). The Reynolds number is kept at 20,000 to control the inlet boundary layer thickness, which makes the height of all cases located between the viscous layer and the log-law region in the boundary layer with a dimensionless height h~+=2～80. Reynolds-Averaged Navier-Stokes(RANS) and Large Eddy Simulation(LES) results were validated by experiment. The results show that the pressure loss and heat transfer show different trends with the h~+, which is mainly due to the enhancement of near-wall turbulence caused by the small rib height and the form drag caused by the large rib height. Furthermore, the analysis of near-wall turbulence characteristics given by LES indicates the enhancement of the normal turbulence fluctuation by the small rib within the turbulent boundary layer transition zone dominates the heat transfer enhancement downstream of the rib. the heat transfer is enhanced and the pressure loss is small when the rib height changes in the boundary layer. Which leads to a better overall thermal performance!OTP). The conclusion affirms that micro rib is a potential cooling technique to attain high heat transfer performance with low pressure loss, which is of great significance to enhance the overall efficiency of gas turbine.
机译：在燃气轮机的当前发展中，在有限的冷空气中，气体供应系统中的压力头和由涡轮机叶片内的冷却单元引起的大流量损失之间存在主要矛盾。它导致对冷却技术的要求提供有效的热传递，具有较低的压力损失。表面微湍流器被认为是潜在的冷却技术。在本研究中，进行了数值模拟和实验研究，以评估一个具有不同肋高度的典型2-D微肋的通道中的湍流传热和压力损失。调查的肋高度范围为0.0013〜0.053的通道液压直径比（H / D）。雷诺数保持在20,000以控制入口边界层厚度，这使得位于边界层中的粘性层和逻辑律区域之间的所有情况的高度，其具有无量纲高度H〜+ = 2〜80。通过实验验证了Reynolds-Iveriged Navier-Stokes（RANS）和大涡模拟（LES）结果。结果表明，压力损失和传热显示H〜+的不同趋势，主要是由于近肋骨高度引起的近壁湍流和由大的肋骨高度引起的形状阻力。此外，LES给出的近壁湍流特性的分析表明湍流边界层过渡区内的小肋的正常湍流的增强主导肋道下游的传热增强。热传递增强，当边界层中的肋高度变化时，压力损失很小。这导致更好的总体热性能！OTP）。结论确认，微肋是一种潜在的冷却技术，以实现高压损失的高传热性能，这对于提高燃气轮机的整体效率具有重要意义。

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