ITO thin film thermocouple for transient high temperature measurement in scramjet combustor

<p>Thermocouples have been extensively used for the measurement of temperature since the advent of seebeck effect. Numerous sensors have been developed for temperature measurement, yet measurement of high temperature flowing fluid has been a challenging task. For the measurement of static temperature the measuring device should travel with the fluid at the same speed without disturbing the flow, which is quite unrealistic. So indirect determination of static temperature of flowing fluid is done by using thermocouple exposed into the flowing fluid. Other sensors available for high temperature measurement may lead to problems like resistance in the flow path of fluid which changes the structural dynamics. Thin film thermocouple (TFTC) based on W-W26Re for super high temperature measurement has been investigated which can be used in missiles for surface temperature measurement of nozzle and rocket interior surface. TFTC does not cause disruption in the flow path with maintaining structural integrity. The W-W26Re thermocouple offers advantage of higher seebeck coefficient at high temperature i.e. above 750 K, and usability in vacuum, inert and hydrogen atmosphere. Zirconia Fiber has been proposed as insulation protection material over thermocouple. Modelling and simulation of the TFTC for the temperature range 300 K - 2900 K has been presented. FEA model using PDE has been presented to implement heat equation, current balance quation, Gauss theorem and Neumann boundary condition. The expected voltage production on exposed temperature gradient has been studied.</p>

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Research on Interfacial Diffusion Reliability Model of Thin Film Thermocouple

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.881.77 ◽

2021 ◽

Vol 881 ◽

pp. 77-85

Author(s):

Dong Yang Lei ◽

Yu Feng Sun ◽

Yu Qing Xue ◽

Guang Yan Zhao

Keyword(s):

Thin Film ◽

High Temperature ◽

Diffusion Model ◽

Great Influence ◽

Protective Layer ◽

Reliability Model ◽

Interfacial Diffusion ◽

Parallel Diffusion ◽

High Temperature Measurement ◽

Thin Film Thermocouple

Thin film thermocouple (TFTC) is widely used in high temperature measurement, which is of short response time, less heat residual and integrated structure. Due to the ultra-thin structure of TFTC, the interfacial diffusion has a great influence on its reliability when exposed to high temperature environment, which leads to its performance degradation. Taking thermocouple on the turbine blade as research object, the parallel diffusion model of multilayer thermocouple is proposed based on Fick’s law. The reliability model of the protective layer, the sensitive layer and the insulating layer are established in the basis of the parallel diffusion model. According to the logical correlation among the multilayer films of TFTC, the TTF model of TFTC is given. Finally, an example of reliability model based on multilayer diffusion is simulated by Monte Carlo method, which demonstrates the feasibility of the method and model.

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