Data-driven estimation of entropy production by large scale motions in an intermediate turbine duct
Data-driven estimation of entropy production by large scale motions in an intermediate turbine duct
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DOI：
10.1016/j.ast.2023.108577
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发表时间：
2023-08
影响因子：
5.6
通讯作者：
Chenxing Hu;Mingqiu Zheng;Ziming Yang;Runnan Zou
中科院分区：
文献类型：
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作者：
Chenxing Hu;Mingqiu Zheng;Ziming Yang;Runnan Zou
在现代燃气轮机中，侵略性中间涡轮管道的三维流入物理学与大规模相干运动密切相关，这导致不可逆的空气动力学和热力学能量损失的产生。为了解决这个问题，提出了一种扩展的数据驱动方法，用于估计湍流中的粘度耗散和传热造成的不可逆损失。使用分离涡模拟框架对连接到高压涡轮的侵蚀性中间涡轮管道进行数值研究。通过四元真正交分解分析评估叶尖泄漏涡和转子尾流对管道空气动力学的影响。然后确定与相干结构相对应的熵产生率，并定量评估管道中受非稳态流动运动影响的不可逆损失。结果表明，中间涡轮管道中的相干结构与上游条件密切相关，包括叶尖泄漏流和转子尾流。直接粘性耗散占不可逆损失的大部分，当尖端间隙尺寸为 1.5% 和 3.5% 跨度时，相干扰动耗散分别占总数的 7.25% 和 5.54%。与平均结构相比，相干扰动的流向发展受到限制，随机部分对粘性耗散的贡献很小。该方法提供了估计非定常湍流中不可逆能量损失的系统程序，并强调了非定常空气热力学在涡轮机械设计中的重要性。
In modern gas turbines, the physics of three-dimensional inflow for aggressive intermediate turbine ducts are strongly associated with large-scale coherent motions, which contribute to the production of irreversible aerodynamic and thermodynamic energy losses. To address this problem, an extended data-driven approach for estimating the irreversible losses through viscosity dissipation and heat transfer in turbulent flows is proposed. An aggressive intermediate turbine duct connected to a high-pressure turbine is numerically investigated using the detached-eddy simulation framework. The influence of tip leakage vortices and rotor wakes on the aerodynamics in the duct is assessed through quadruple proper orthogonal decomposition analysis. The entropy production rate corresponding to the coherent structures is then identified, and the irreversible losses in the duct subject to unsteady flow motions are quantitatively evaluated. The results indicate that the coherent structures in the intermediate turbine duct are strongly associated with the upstream conditions, including the tip leakage flow and rotor wakes. Direct viscous dissipation accounts for the majority of the irreversible losses, with coherent perturbed dissipation contributing to 7.25% and 5.54% of the total for tip gap sizes of 1.5% and 3.5% span, respectively. The streamwise development of coherent perturbations is restricted compared with that in the mean structure, and the stochastic part contributes little to the viscous dissipation. The proposed method provides a systematic procedure for estimating the irreversible energy losses in unsteady turbulent flow, and highlights the significance of unsteady aero-thermodynamics in the design of turbomachinery.