Wire Temperature Research Articles

Towards a completely 3D printed hot wire anemometer

Here, we demonstrate a completely 3D printed flow sensor that operates on the principle of Joule heating and hot wire anemometry. Finite element modeling with experimentally determined properties of the fused deposition modeling filaments was used to confirm the feasibility of such a sensor. Steady-state simulations were used to calculate the operating voltage that produces the maximum sensitivity while keeping the wire temperature 10 °C below the glass transition temperature. At this operation voltage, the transient simulations indicated a response time of 10 s (>95 % of the change in resistance) and a flow sensitivity of −2.33 Ω/sccm, or a relative change in resistivity of 0.036 per sccm. The flow sensor was realized through fused deposition modeling of a combination of electrically conductive and non-conductive filaments. A proof of concept was demonstrated by simultaneously recording infrared images and measuring the change in resistance of the sensor. Experimentally, higher operation voltage (12−15 V) was required compared to the simulations. At 12 V, the flow sensitivity ranged from 0.014 to 0.032 per sccm, whereas at 15 V, it ranged from 0.039 to 0.065 per sccm. The completely 3D printed flow sensors hold potential to be used as an alternate to existing range of flow sensors, more prominently, manufacturing on-demand and integrating with product packaging.

Heat Capacity and Thermal Damping Properties of Spin-Crossover Molecules: A New Look at an Old Topic.

The thermally induced spin-crossover (SCO) phenomenon in transition metal complexes is an entropy-driven process, which has been extensively studied through calorimetric methods. Yet, the excess heat capacity associated with the molecular spin-state switching has never been explored for practical applications. Herein, the thermal damping effect of an SCO film is experimentally assessed by monitoring the transient heating response of SCO-coated metallic microwires, Joule-heated by current pulses. A damping of the wire temperature, up to 10%, is evidenced on a time scale of tens of microseconds due to the spin-state switching of the molecular film. Fast heat-charging dynamics and negligible fatigability are demonstrated, which, together with the solid-solid nature of the spin transition, appear as promising features for achieving thermal energy management applications in functional devices.

Analysis of surrounding gas temperature influence on thermocouple measurement temperature

When thermocouple is used to measure high temperature gas flow, the measured temperature, i.e., the thermocouple bead temperature is not exactly the gas temperature. The bead temperature results from the bead energy balance including the convection with the gas flow, the radiation with the environment and the gas, the conduction with the thermocouple wire near the bead. The wire temperature is determined by its own energy balance relating to the gas temperature contacting the wire. Through the wire conduction, the bead temperature is related to the gas temperature around the wire near the bead. The one-dimensional thermocouple heat transfer simulation code was developed and validated by the elaborate experiment. In the current study, this code is used to study the influence of the surrounding gas temperature on the bead temperature. Of course, the gas temperature far away from the bead will not influence the bead temperature. The size of the surrounding region which could influence the bead temperature is identified and its relation with the flow condition and the thermocouple size is analyzed. The quantitative bead temperature variation with the temperature gradient inside this region is studied.

Conformal Devices for Thermal Sensing and Heating in Biomedical and Human–Machine Interaction Applications

Thermal ablation has been adopted as one of the most common cancer treatment approaches in medical surgery. By increasing the temperature (>50 °C) on the cells, the cells are destroyed because of denaturation. Herein, an ultrathin Archimedean spiral pattern heater/sensor technology is introduced which can perform ablation by attaching conformally onto the organs for precise heating and temperature sensing. In the heater mode, the heater temperature is linearly proportional to the input joule heating power up to 400 mW. In the sensor mode, the temperature of the conformal metal wire is also linearly related to the resistance by the temperature coefficient of resistance (TCR). The conformal heater to perform ex vivo ablation on the porcine liver is utilized. By further integrating the devices with robotic palm and perform heat‐and‐sense interactions, a human–machine interface (HMI) apparatus is demonstrated which can be potentially applied in surgical robots or other tactile stimulation systems.

Influence of surrounding gas temperature on thermocouple measurement

When thermocouples are used to measure gas temperature, the measured temperature, i.e., the thermocouple bead temperature, is not equal to the gas temperature. The bead temperature results from the bead energy balance including the convection with the gas flow, the radiation with the environment and the gas, the conduction with the thermocouple wires. The wire temperature is determined by its own energy balance relating to the gas temperature contacting the wire. Through the wire conduction, the bead temperature is in fact related to the gas temperature surrounding the bead. The influence of the surrounding gas temperature on the thermocouple bead temperature is studied numerically with the one-dimensional code here. The effect length, which is the size of the influencing region, is identified and its relation with the flow condition and the thermocouple property are analyzed. Analytical expressions are also deducted to calculate the effect length. The analytical and numerical results show very good agreement. The analytical effect length follows the same trend as the numerical value when the size and thermal conductivity of the thermocouple and the velocity and temperature of the incoming gas are varied. The analytical effect length deviates from the numerical value by less than 14.3%.

Experimental and modeling analysis of thermal characteristics in carbon fiber wires

AbstractTo understand the thermal characteristics of carbon fiber heating wires, we tested the heating rules of carbon fiber heating wires with inner core tows of 12k and 24k and different lengths. We found that the surface temperature of the carbon fiber heating wires rose and fell quickly when the power supply was turned on and off by 82.9 and 18.3°C/min, respectively. After the quick rise period, the surface temperature tended to be steady with ±2°C of fluctuation; the steady temperature decreased as the length increased. With an increase in the length from 7 to 12 m, the steady temperature of the 12k and 24k wires reduced from 122°C and 166°C to 53°C and 71°C, respectively. Using the COMSOL Multiphysics software to simulate the carbon fiber heating wires, the simulated surface temperatures were in good agreement with the experimental results, with errors less than 7%. The convective and radiative heat transfer of the simulated carbon fiber electric heating wire decreased with an increase in length and the number of tows, and the convective heat transfer was much higher than the radiative heat transfer to indicate that the convective heat transfer is the main heat transfer mode in the heat dissipation of the carbon fiber electric heating wire. Results indicate that there is a rapid increase in temperature when power is on, and thereafter temperature remains constant. These are the important characteristics of carbon fiber heating wires.

Influence of temperature on the passive control of a rotating machine using wires of shape memory alloy in the suspension

This paper deals with the passive control of mechanical vibrations of rotating machines using wires of shape memory alloys (SMA). Unlike other classes of smart materials, the proposed technique allows for simpler mechanical construction and offers new technological possibilities. Both numerical simulations and experimental tests have been performed in the present investigation. The numerical results reveal that the SMA wires can reduce the amplitude of lateral vibrations of a rotating shaft to acceptable levels, as shown by time responses and orbit curves. Experimentally, it has been demonstrated that SMA wires confirm the simulation results regarding the reduction of the lateral vibration of a rotor system. It has also been verified that the temperature of the SMA wire can be employed to tune the vibration control system. In this context, passive control architecture is recommended in order to take advantage from an intrinsic characteristic of SMA wires.

Development of a Non-destructive Testing Method for Assessing Thermal Status of District Heating Pipes

Pre-insulated district heating (DH) pipes have been in use for more than 40 years. The thermal performance of these pipes decreases over time as a result of thermal and mechanical aging, which leads to higher heat energy losses. A non-destructive method based on a cooling method is under development for assessing the thermal performance of a DH network. The method utilizes the copper wire, which is already embedded in the polyurethane insulation for detection of water leakage, as a sensor for measuring the temperature at the position of the copper wire. The method involves a shutdown of a selected part of a network for less than 2 h and evaluating the cooling process by measuring the supply pipe temperature and the temperature of the copper wire. The method was applied in a DH network during heating season. The thermal conductivity calculated by the method [0.027 W/(m K)] was in good agreement with the reference value [0.026 W/(m K)]. The cooling of the network can be measured at a valve or at other more easily accessible steel parts. It was also shown that the method is applicable for DH networks without a copper wire. However, a temperature measurement is needed on the casing pipe.

Simulation of Electric Networks Modes Using Steady-State and Heat Balance Equations

In the traditional calculations of the steady-state mode of the electrical network, the dependences of the active resistances of the overhead line wire on the ambient temperature and currents in the branches are not taken into account. However, the temperature is a function of the active power losses, the power losses are a function of the resistance and current, and the resistance is temperature dependent. Therefore, these relations should be related to the traditional equations for stationary regimes. In order to increase the accuracy of steady-state calculations, a temperature correction of the resistance of the branches is required. In this paper, we present a method based on the joint solution of nonlinear equations of the steady-state electric network regime and the thermal balance of the wires of overhead lines. The algorithm and the program of calculation of the steady-state mode of an electric network taking into account dependence of active resistances of a wire of an overhead line on ambient temperature and currents in branches have been developed. The quantitative influence of the load current, wire temperature, wind speed, solar radiation on the active resistance of the wires has been estimated, and the errors in calculating annual variable energy losses have been determined. Numerical experiments were carried out for a 6-node modified version of the IEEE test system and equivalent circuit of 110 kV. The results of the calculations of the steady-state regime on various test circuits showed that the non-account of the temperature dependence of the active resistances might cause errors in power loss for individual loaded lines up to 10 %, and for total losses of the system – up to 30 %. This is unacceptable in simulating the modes of the electric network. The results of simulation of steady-state regimes taking into account the temperature dependence of the resistance of the wires are presented on the example of 6-node and 7-node circuits.

Practical Design and Experimental Test of MgB2 Magnets for 300 kW-Class Superconducting Induction Heater

A shape and characteristics of Superconducting magnets used in superconducting applications are effected by purposing of a device and these coils are wound with various superconducting wires such as high temperature superconducting (HTS) wire and low temperature superconducting (LTS) wire. MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> wire is the one of the wires which can compensate the disadvantages of each wire. Therefore, if we adopt MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> wire to superconducting applications, we get advantages such as operating temperature with cryogen free cooling system and wire's price. In this paper, the author designs, fabricates and tests MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet for a 300 kW-class DC superconducting induction heater. Firstly, MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet is designed and analyzed using finite elements method for a 300 kW-class superconducting induction heater. Secondly, the magnet is fabricated using dry-winding and metal insulation method. Finally, MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet is stacked and assembled into conduction cooling property measurement system for evaluate its performance and characteristics. As a result, MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet guaranties a satisfactory performance with low price and highest critical temperature among LTS wires. The low temperature as 10 K, which is the operating temperature of the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> magnet, can be achieved by a conduction cooling system. This study will be effectively utilized for a 300 kW-class superconducting induction heater and other superconducting magnet applications.

Effect of catalyst size on flameless combustion's hysteresis characteristics of air-gas mixtures with combustible gas's impurities

Analytical models of heat and mass transfer's hysteresis and combustion kinetics of combustible gas impurities on a metal catalyst particle (wire) in the presence of only one onesided reaction are proposed. The analysis is carried out taking into account thermal diffusion and depending on the catalyst's size and the gas-air mixture's temperature. The dependences of platinum wire's temperature on hydrogen-air mixture's temperature at various wire diameters are presented. Decrease in the wire's diameter under unchanged other conditions leads to a decrease in the hysteresis region and its further degradation. The method used for analytical determination of hysteretic regions and degradation points, which lies in representing the desired dependences of operating parameters in a parametric form (parameter is catalyst's temperature). Analytical dependence (spinodal) gas-air mixture's temperature on catalyst's diameter was found that describes all critical points, including degradation points.The value of the diameter's and temperature's wire catalyst, the mixture's temperature, which correspond to critical condition’s degradation, were obtained in explicit form.

ОЦЕНКА ВОЗМОЖНОСТИ ИСПОЛЬЗОВАНИЯ ВЫСОКОСКОРОСТНОЙ КОНТАКТНОЙ ПОДВЕСКИ КС-400 ДЛЯ СИСТЕМ ЭЛЕКТРИЧЕСКОЙ ТЯГИ ПОСТОЯННОГО ТОКА ПОВЫШЕННОГО НАПРЯЖЕНИЯ

The paper considers the possibility to use KS-400 high-speed catenary suspension for direct current traction systems with increased voltage of 12, 18 and 24 kV. It also presents the temperature of catenary wires at tractive rolling stock passing with maximum possible current. It is established that the passage of a current collector under the worst conditions of heat release is insignificant for catenary wires even at a voltage of 12 kV. According to the results of calculations at voltage of 12 kV and 18 kV, the current collector is the limiting element in the standby and traction modes with maximum current.

Electromagnetic Field and Changing the Ambient Temperature of High Tension Wires

Electromagnetic Field and Changing the Ambient Temperature of High Tension Wires

Numerical and Experimental Study of Thermal Response of an Electrified Nickel Wire

An electrified nickel wire can produce heat. The heat is transferred to the environment around the wire radiation. However, the temperature produced by the wire will differ depending on the number of voltages supplied by the power source. Here, we do an experiment to measure the temperature of stand-up wire at each voltage of 4.5 V, 6.0 V, 7.5 V, 9.0 V, and 12 V. As a comparison, numerical measurements are done by JavaScript program. We show that the highest temperature of the wire approaches 314 K at 12 V. To equalize the temperature in both methods, the numerical scale factor of time and current in numerical measurements are changed according to the voltage. As a result, temperatures produced in both methods have minimal gap difference with error percentage below 0.5%. In conclusion, the experiment results were used to determine the scaling parameters to approach the ideal thermal response curve in actual values.

Electromigration Activation Energies in Alternative Metal Interconnects

The electromigration (EM) activation energy ( $\text {E}_{\text {A}}$ ) of alternative metals, such as Ru and Co, was obtained using low-frequency noise (LFN) measurements. High activation energies were expected, but values of ≈1 eV are found, most likely related to diffusion along with the metal-dielectric interface. Wafer-level accelerated EM tests were carried out to compare the LFN $\text {E}_{\text {A}}$ to the EM $\text {E}_{\text {A}}$ in the Ru wires. The calculation of the EM $\text {E}_{\text {A}}$ is found to be strongly dependent on the assumed temperature profile in the wire due to Joule heating (JH). The temperature profile was calculated analytically, assuming the contacts are at ambient temperature. For a void forming in direct proximity of the contact, the EM $\text {E}_{\text {A}}$ then matches the LFN $\text {E}_{\text {A}}$ . For a void at average wire temperature (ambient + JH), $\text {E}_{\text {A}}\approx $ 2 eV. In addition to demonstrating the application of LFN to study EM in alternative metals, this article also cautions for the impact of JH on the calculation of $\text {E}_{\text {A}}$ in interconnects.

Optimization of thermal aware multilevel routing for 3D IC

Due to the technological advancements, the three dimensional Integrated Circuits become the most popular technology. But it has the major drawback of increased time consumption as well power consumption. This happens because of the increased wire length and routing path for connecting the components in chip. Thus it is essential to reduce the wire length for the purpose of enhancing the circuit speed and minimize the power dissipation. But there may be a chance of temperature rise due to the heat generated by the slacked layers which also needs to be reduced. Several traditional approaches have addressed the issues of temperature rise and layer assignment. But the utilization of through-silicon-via is considered. Thus a new stochastic based genetic algorithm is proposed in this work for reducing the thermal estimations. Also the length of wire can be reduced by determining the minimal path so as to connect the components. Both partitioning and routing process takes place in this approach. The performance of the proposed approach is analyzed using ISPD2008 dataset. Also the results of this stochastic based model are compared with the existing algorithm. The superiority of this proposed approach is proved with reduced wire length and temperature estimations.

Effects of Hot Wire Temperature on Properties of GeSi:H Films with High Hydrogen Dilution by Hot-Wire Chemical Vapor Deposition

GeSi:H films are prepared by hot-wire chemical vapor deposition (CVD) with high hydrogen dilution, DH=98%. Effects of hot wire temperature (Tw) on deposition rate, structural properties and bandgap of GeSi:H films are studied with surface profilemeter, Raman spectroscopy, Fourier transformed infrared spectroscopy, and UV-VIS-NIR spectrophotometer. It is found that the deposition rate (Rd) goes up with increasing of Tw, but increasing rate of Rd declines when Tw⩾1 550 °C. High Tw is beneficial to the formation of Ge-Si, but it has little effect on relative contents of the hydrogen bonds (Ge-H, Si-H, etc.) in the films. In the Tw range of 1 400–1 850 °C, the maximum bandgap of the GeSi:H films is 1.39 eV at Tw =1 450 °C and the band gap decreases with Tw increasing when Tw⩾1 450 °C.

Optimizing the Parameters of Hot-wire CNC Machine to Enhance the Cutting of Plastic Foam

Hot-wire cutting is one of the important, non-traditional thermomechanical way to cut polymer, usually expanded foam and extruded foam, in low volume manufacturing. The study and analysis of Hot-Wire cutting parameters play an important role to enhance the quality and accuracy of the process and products. The effects on the surface have been investigated by using experimental tests designed according to the Taguchi orthogonal array (OA). In this study, four parameters with five levels for each parameter have been used: [temperature of wire (A) (100, 120, 130, 150, 160) °C], [diameter of wire (B) (0.3,0.4,0.5,0.7,0.8) mm], [velocity of cutting (C) (200, 300,400,500,600) mm/min], [and density of foam (D) (0.01,0.027,0.029,0.032,0.037) g/cm3]. Statistical software (MINITAB17) used to find the optimum conditions, which they are in Material Removal: 100 ˚C, 0.5 mm, 300mm/min, 0.032 g/cm3.

Facile and Efficient Atomic Hydrogenation Enabled Black TiO2 with Enhanced Photo‐Electrochemical Activity via a Favorably Low‐Energy‐Barrier Pathway

AbstractBlack TiO2 has demonstrated a great potential for a variety of renewable energy technologies. However, its practical application is heavily hindered due to lack of efficient hydrogenation methods and a deeper understanding of hydrogenation mechanisms. Here, a simple and straightforward hot wire annealing (HWA) method is presented to prepare black TiO2 (H–TiO2) nanorods with enhanced photo‐electrochemical (PEC) activity by means of atomic hydrogen [H]. Compared to conventional molecular hydrogen approaches, the HWA shows remarkable effectiveness without any detrimental side effects on the device structure, and simultaneously the photocurrent density of H–TiO2 reaches 2.5 mA cm−2 (at 1.23 V vs reversible hydrogen electrode (RHE)). Due to the controllable and reproducible [H] flux, the HWA can be developed as a standard hydrogenation method for black TiO2. Meanwhile, the relationships between the wire temperatures, structural, optical, and photo‐electrochemical properties are systematically investigated to verify the improved PEC activity. Furthermore, the density functional theory (DFT) study provides a comprehensive insight not only into the highly efficient mechanism of the HWA approach but also its favorably low‐energy‐barrier hydrogenation pathway. The findings will have a profound impact on the broad energy applications of H–TiO2 and contribute to the fundamental understanding of its hydrogenation.

Induction Coil Heating Improves the Efficiency of Insect Olfactory Studies

Electroantennography (EAG) is a commonly used method to study the olfactory responses of insects, but many behaviorally relevant odorant responses are difficult to evaluate because only a small amount of chemical sample is available in the vapor phase. We have assembled a coupled induction heating-electroantennogram (IH-EAG) system to improve the release efficiency of tested compounds. This system allows precise temperature control from room temperature to 600 C of the carbon steel wire without changing significantly the air delivery temperature to the antennae. After heating to 135 C (wire temperature read by a calibrated thermocouple), EAG response to 0.1 mg of DEET increased from 0.11 to 0.33 mV, which is not significantly different from the EAG response to 1 mg at room temperature (ca. 25 C). Likewise, response to 1-octen-3-ol was detected at 0.1 mg after heating to 135 °C and was equivalent to 1 mg at room temperature. For the low volatility compound VUAA-1, an experimental insect repellent, the EAG response increased 60-fold, from 0.16 to 9.52 mV after heating to 500 C without degradation of the sample, as determined by NMR. Overall, this system can easily reduce the amount of chemical used in an EAG assay up to 10-fold and provided the compound is not thermally labile, allows for rapid testing of slow acting, less volatile compounds for eliciting an olfactory response from insects or other animals.