scholarly journals 3D Sequential Spacal and Thermal Measurements

2021 ◽  
Author(s):  
Lifong ZOU ◽  
Farida FORTUNE ◽  
L. NIBALI ◽  
N. GKRANIAS ◽  
N. MARDAS ◽  
...  
Keyword(s):  
Thermal Measurements

scholarly journals Thermoelectric Sensor Coupled Yagi–Uda Nanoantenna for Infrared Detection

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 527
Author(s):  
Waleed Tariq Sethi ◽  
Olivier De Sagazan ◽  
Mohamed Himdi ◽  
Hamsakutty Vettikalladi ◽  
Saleh A. Alshebeili
Keyword(s):  
State Of The Art ◽  
Infrared Detection ◽  
Single Element ◽  
Center Wavelength ◽  
Resonance Response ◽  
Thermal Measurements ◽  
Radiation Induced ◽  
Thermoelectric Sensor ◽  
Junction Array ◽  
First Time

We present an experimental demonstration of a thermoelectric sensor coupled with a nanoantenna as an alternative option for detecting infrared energy. Two nanoantenna design (single element and an array) variations based on Yagi-Uda technology and one separate nano-thermoelectric junction array were fabricated and tested. The nanoantennas were tuned to operate and respond at a center wavelength of 1550 nm (193.5 THz) optical C-band window, but they also exhibited a resonance response when excited by lasers of various wavelengths (650 nm and 940 nm). The radiation-induced electric currents in the nanoantennas, coupled with a nano-thermoelectric sensor, produced a potential difference as per the Seebeck effect. With respect to the uniform thermal measurements of the reference nanoantenna, the experiments confirmed the detection properties of the proposed nanoantennas; the single element detected a peak percentage voltage hike of 28%, whereas the array detected a peak percentage voltage hike of 80% at the center wavelength. Compared to state-of-the-art thermoelectric designs, this was the first time that such peak percentage voltages were experimentally reported following a planar design based on the Seebeck principle.

Experimental Evidence of Temperature Ratio Effect on Turbine Blade Tip Heat Transfer

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
H. Jiang ◽  
Q. Zhang ◽  
L. He ◽  
S. Lu ◽  
L. Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Boundary Conditions ◽  
Transfer Coefficient ◽  
Experimental Evidence ◽  
Turbine Blade ◽  
Tip Clearance ◽  
Temperature Ratio ◽  
Thermal Boundary Conditions ◽  
Thermal Measurements

Determination of a scalable Nusselt number (based on “adiabatic heat transfer coefficient”) has been the primary objective of the most existing heat transfer experimental studies. Based on the assumption that the wall thermal boundary conditions do not affect the flow field, the thermal measurements were mostly carried out at near adiabatic condition without matching the engine realistic wall-to-gas temperature ratio (TR). Recent numerical studies raised a question on the validity of this conventional practice in some applications, especially for turbine blade. Due to the relatively low thermal inertia of the over-tip-leakage (OTL) flow within the thin clearance, the fluids' transport properties vary greatly with different wall thermal boundary conditions and the two-way coupling between OTL aerodynamics and heat transfer cannot be neglected. The issue could become more severe when the gas turbine manufacturers are making effort to achieve much tighter clearance. However, there has been no experimental evidence to back up these numerical findings. In this study, transient thermal measurements were conducted in a high-temperature linear cascade rig for a range of tip clearance ratio (G/S) (0.3%, 0.4%, 0.6%, and 1%). Surface temperature history was captured by infrared thermography at a range of wall-to-gas TRs. Heat transfer coefficient (HTC) distributions were obtained based on a conventional data processing technique. The profound influence of tip surface thermal boundary condition on heat transfer and OTL flow was revealed by the first-of-its-kind experimental data obtained in the present experimental study.

The Comparison of Aerodynamic Performance Data Acquired From Thermal Measurements and a Torquemeter on a Compressor Impeller

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Natalie R. Smith ◽  
Timothy C. Allison ◽  
Jason C. Wilkes ◽  
Christopher Clarke ◽  
Michael Cave
Keyword(s):  
Steady State ◽  
Heat Loss ◽  
Performance Metrics ◽  
Aerodynamic Performance ◽  
Performance Data ◽  
Testing Time ◽  
Southwest Research Institute ◽  
Significant Difference ◽  
Thermal Measurements ◽  
Isentropic Efficiency

Full-thermal heat-soak of machinery is vital for acquiring accurate aerodynamic performance data, but this process often requires significant testing time to allow all facility components to reach a steady-state temperature. Even still, there is the potential for heat loss in a well-insulated facility, and this can lead to inaccurate results. The implementation of a torquemeter to calculate performance metrics, such as isentropic efficiency, has two potential advantages: (1) the method is not susceptible to effects due to thermal heat loss in the facility, and (2) a torquemeter directly measures actual torque, and thus work, input, which eliminates the need to fully heat-soak to measure the actual enthalpy rise of the gas. This paper presents a comparison of aerodynamic performance metrics calculated both from data acquired with thermal measurements as well as from a torquemeter. These tests were conducted over five speedlines for a shrouded impeller in the Southwest Research Institute Single Stage Test Rig facility. Isentropic efficiency calculated from the torquemeter was approximately 1–2 efficiency points lower than the isentropic efficiency based on thermal measurements. This corresponds to approximately 0.5–1 °C in heat loss in the discharge collector and piping. Furthermore, observations from three full-thermal heat-soak points indicate the significant difference in time required to reach steady-state performance within measurement uncertainty tolerances between the torque-based and thermal-based methods. This comparison, while largely suspected, has not yet been studied in previous publications.

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