应用Transition k-kl-ω转捩模型对内冷叶片气热耦合的数值模拟

Numerical Simulation of Coupled Heat Transfer for an Innercooled Blade by Applying Transition k-kl-ω Transition Model

关键词:  转捩  冷却  气热耦合  对流换热系数准则

Key words:  Transition  Cooling  Gas thermal coupled  Heat transfer coefficient criteria

摘要:

选取NASA-Mark II跨声速叶片为算例,研究了Transition k-kl-ω转捩模型在内冷叶片气热耦合计算中的应用,探讨了整场耦合与冷却通道内采用对流换热系数准则耦合的差异。结果表明,该转捩模型相比其它全湍流模型能够更准确预测附面层内的层流和转捩状况；由于Transition k-kl-ω转捩模型转捩前期采用层流动能来描述扰动的发展,避免了使用含有来流湍流度的经验公式,引入了“分裂机制”来描述层流与湍流脉动间的相互作用,并且在旁路转捩和自然转捩源项模化中加入了Tollmien-Schlichting波的影响,对强激波后的温度计算相比常用的间歇因子转捩模型与实验值更吻合；换热系数准则耦合用于冷却通道传热计算,避免了冷却通道边界条件带来的误差,计算结果与实验吻合较好,更易于工程应用。

Abstract:

NASA-MarkII transonic blade was selected as an example in this paper to investigate the application of the Transition k-kl-ω model in gas thermal coupling calculation of an innercooled blade, and to analysis the difference between the whole coupled method and heat transfer coefficient criteria coupled method in cooling channels. Compared with other turbulence models, the transition model is capable of predicting the boundary layer of laminar flow and the transition state more accurately. In the Transition k-kl-ω model, laminar kinetic energy was used to describe the development of disturbance in the early stage so as to avoid the empirical formula which includes flow turbulence intensity, and the“split system” was introduced into this model to describe the interaction between laminar and turbulent fluctuation. Besides, Tollmien-Schlichting wave was added in the bypass transition and natural transition source term, as a result, the computational temperature results for behind the strong shock wave agreeed better with the experimental value than that obtained with intermittent transition factor model. Using the coupled heat transfer coefficient criteria in the cooling channel heat transfer calculation, which removes the error caused by cooling channel boundary conditions, leads to better agreement with the experimental results and easier engineering applications. 