基于光强方法的双层温敏漆点阵的热流密度测量

Light intensity based heat flux measurement with double-layer temperature-sensitive paint lattices

为提高长时间热流密度测量的精度,提出了一种基于双层温敏漆点阵涂层的热流密度直测技术。该技术运用精细喷涂技术在厚度均匀的透明膜L2的上下表面分别喷涂错位分布的温敏漆点阵L3和L1。结合图像边缘检测和粒子图像测速的询问算法确定温敏漆点阵位置,提取温敏漆喷涂点的光强,由光强-温度标定关系可以测得L1和L3上的温度分布;分别采用Cook-Felderman方法和Fourier导热定律计算热流密度,并与热流密度传感器测量结果进行比较,结合热渗透时间分析不同方法的适用性。结果表明:双层温敏漆点阵方法既能用Cook-Felderman方法捕捉短时间热冲击下的瞬态热流密度,又能用Fourier导热定律测量长时间稳态的热流密度,在高速热流密度测量中有一定的应用前景。

An intensity-based method for direct heat flux measurement with double-layer temperature-sensitive paint(DL-TSP)lattices has been proposed in this study.With the aid of an accurate spray technique,temperature-sensitive paint lattices L3 and L1 are sprayed in a staggered arrangement on the upper and lower surfaces of a transparent film L2 of uniform thickness,respectively.Utilizing image edge detection and interrogation of particle image velocimetry(PIV)to locate the lattices,the light intensity of spray points of the temperature-sensitive paint can be extracted,and the corresponding temperature distributions of L1 and L3 can be obtained from the light intensity-temperature calibration relation.The heat flux is calculated using both the Cook-Felderman method and the Fourier’s law,which are compared with data from the heat flux sensor.The applicability of different methods is analyzed based on the thermal penetration time.The results indicate that the double-layer temperature-sensitive paint lattice method can not only capture the transient heat flux under short-term thermal shock using the Cook-Felderman method,but also measure the long-term steady-state heat flux using the Fourier’s law.The present method has certain application prospects in the heat flux measurement of high-speed flows.