A thin-film thermocouples (TFTCs) sensor based on silicon carbide substrate, 95 wt% tungsten–5 wt% rhenium (W-5Re) and 74 wt% tungsten–26 wt% rhenium (W-26Re) thermosensitive part with aluminum oxide protective coating layer was designed and fabricated by radio frequency (RF) magnetron sputtering. It exhibited a high thermoelectric voltage of 35.51 mV when the temperature difference was 1240 °C (the hot junction temperature was 1420 °C), with an average Seebeck coefficient of 28.63 µV/°C, which was 27% larger than the standard C-type thermocouple wires at the same temperature difference. The repeatability error was ±4.1%, the drift rate was 9.6 °C/h for 10 h and the laser response time was 0.36 ms. Compared to the traditional thermocouple, it could provide long-term temperature testing within 1420 °C for the requirement of high-temperature measurement and high response speed.

A novel probe-type thin film thermocouple has been fabricated successfully for high temperature measurement applications. WRe26 (tungsten–26% rhenium)–In₂O₃ thermoelectric materials were used in the thermocouples to achieve high thermoelectric output and high temperature resistance. The films were deposited on a cylindrical substrate by magnetron sputtering technology. The annealing process of the thermocouples was studied to achieve optimal performance. The calibration results showed the thermoelectric output of WRe26–In₂O₃ thin film thermocouples reached 93.7 mv at 700 °C, and its sensitivity was 165.5 µV/°C under the temperature of the cold junction, which was 133.8 °C. The thermocouples developed in this work have great potential for practical applications.

WRe26-In₂O₃ (WRe26 (tungsten-26% rhenium) and In₂O₃ thermoelectric materials) thin film thermocouples (TFTCs) have been fabricated based on magnetron sputtering technology, which can be used in temperature measurement. Many annealing processes were studied to promote the sensitivity of WRe26-In₂O₃ TFTCs. The optimal annealing process of the thermocouple under this kind of RF magnetron sputtering method was proposed after analyzing the properties of In₂O₃ films and the thermoelectric voltage of TFTCs at different annealing processes. The calibration results showed that the WRe26-In₂O₃ TFTCs achieved a thermoelectric voltage of 123.6 mV at a temperature difference of 612.9 K, with a sensitivity of up to 201.6 µV/K. Also, TFTC kept a stable thermoelectric voltage output at 973 K for 20 min and at 773 K for two hours. In general, the WRe26-In₂O₃ TFTCs developed in this work have great potential for practical applications. In future work, we will focus on the thermoelectric stability of TFTCs at higher temperatures.

A comparative analysis of pressure drop of different flow pattern of two tube bundles was done. The results show that: the pressure drop of bubble flow is maximum, followed by intermittent flow, and mist flow becomes the minimum. Based on the statistical analysis of the different pressure signals, the power spectrum density versus frequency of the signals for major flow patterns was obtained. It is found that the flow patterns can be identified in accordance with the power spectrum density. The recurrence quantification analysis method was used to study the dynamic characteristics of differential pressure fluctuating signals of bubbly flow, intermittent flow, mist flow patterns. The research indicated isolated points texture appeared on recurrence plot for the bubbly flow. Both dispersed points texture and massive texture appeared on recurrence plot for the intermittent flow with strong chaos characteristic. The recurrence plot of mist flow whose idicated periodic is outstanding has a good diagonal texture. The recursion texture of differential pressure fluctuating signals could well reflect the evolution characteristics of flow pattern, and the recurrence characteristics quantities were obvious to the variations of superficial gas velocity and provided a new idea for investigation of gas-liquid two-phase flow mechanism.