Dependence of Heat Transfer to a Pulsating Stagnation Flow on Pulse Characteristics
Dependence of Heat Transfer to a Pulsating Stagnation Flow on Pulse Characteristics
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DOI：
10.2514/3.645
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发表时间：
1995
影响因子：
2.1
通讯作者：
E. Mladin;D. Zumbrunnen
中科院分区：
文献类型：
--
作者：
E. Mladin;D. Zumbrunnen
采用详细的边界层模型来确定脉冲形状、频率和幅度对在事件周期性脉动流下方形成的平面停滞区域中的瞬时和时间平均对流换热的影响，该流场具有与温度相关的运动粘度和导热率。低频/高振幅流量脉动与控制方程中的非线性之间的相互作用导致时间平均努塞尔数减少高达 16%。预测与实验结果非常吻合。因此，提出了一种抑制传热的装置，其可以实际应用于叶片暴露于周期性流动的燃气轮机。相图、庞加莱图、傅里叶谱和李亚普诺夫指数用于阐明最复杂的解决方案。
A detailed boundary-layer model is implemented to ascertain the influence of pulse shape, frequency, and amplitude on instantaneous and time-averaged convective heat transfer in a planar stagnation region formed beneath an incident periodic, pulsating flow with temperature-dependent kinematic viscosity and thermal conductivity. Interactions between low-frequency/high-amplitude flow pulsations and the nonlinearities in the governing equations lead to reductions in time-averaged Nusselt numbers up to 16%. Predictions are in good agreement with experimental results. A means to suppress heat transfer is thus suggested that may have practical application to gas turbines where blades are exposed to a periodic flow. Phase portraits, Poincare maps, Fourier spectra, and Lyapunov exponents are used to elucidate the most complex solutions.