The magnitude of surface heat flux and its accurate estimation are very crucial owing to their applicability in impulsive thermal loads for high-speed flights. The correctness of such heat flux is associated with the implications from highly responsive thermal sensors in ground-based aerodynamic studies. In the present study, the performance effectiveness of an indigenous, in-house-made coaxial thermal probe (CTP) is validated against a standard silver thin film gauge (TFG) counterpart. The thermal probe has been fabricated in-house from two metal alloys; chromel (3.25 mm diameter and 10 mm length) and constantan (0.91 mm diameter and 15 mm length), by disposing one in the annulus of another coaxially, subsequently clubbed by a thin layer of epoxy in between them. Similarly, the thin film gauge is fabricated by putting silver paste (~1 µm thickness) on the pyrex substrate (3.25 mm diameter, 10 mm length). The fabrication process is followed by different calibration activities to determine the characteristics constants for sensors (sensitivity, thermal product value for CTP, and temperature coefficient of resistance for TFG). Both the probes are tested in a highly transient environment in a shock tube that generates high density, high pressure, and high enthalpy flows. The response time of the CTP and TFG are found to be 265 µs and 240 µs, respectively. The heat flux values estimated through temperature responses are having a nice match for CTP as well as TFG with a deviation in peak heat flux value within a range of ±2%. A similar trend and magnitude are also re-assured through numerical simulation within an uncertainty band of ±1.5%. The exhaustive study carried out in a shock tube has assured the performance and reliability of a CTP. Hence, it is recommended as an effective heat flux sensor for routine measurements in impulsive heat loadings.

由于表面热通量适用于高速飞行的脉冲热负荷，因此其非常重要。这种热通量的正确性与基于地面的空气动力学研究中的高响应热传感器的含义相关。在本研究中，相对于标准的银薄膜量规（TFG），对本地自制的同轴热探针（CTP）的性能有效性进行了验证。该热探针是由两种金属合金在内部制造而成的。铬（直径3.25毫米，长度10毫米）和康斯坦（直径0.91毫米，长度15毫米），方法是将一个铬镍铁合金同轴地放置在另一个铬铁环中，然后在它们之间夹上一层环氧树脂薄层。相似地，薄膜量规是通过将银浆（厚度约1 µm）放在耐热玻璃基板上（直径3.25 mm，长度10 mm）制成的。在制造过程之后进行不同的校准活动，以确定传感器的特性常数（灵敏度，CTP的热乘积值和TFG的电阻温度系数）。两种探针均在激波管中的高瞬态环境中进行了测试，该激波管会产生高密度，高压和高焓流。发现CTP和TFG的响应时间分别为265 µs和240 µs。通过温度响应估算的热通量值与CTP和TFG非常匹配，峰值热通量值的偏差在±2％的范围内。通过数值模拟，也可以在±1.5％的不确定性范围内确保相似的趋势和幅度。在冲击管中进行的详尽研究确保了CTP的性能和可靠性。因此，推荐将其作为有效的热通量传感器用于脉冲热负荷的常规测量。