Calculation of steady-state temperature rise of water-cooled buried cables using a new iterative method

1969 ◽  
Vol 116 (1) ◽  
pp. 101 ◽  
Author(s):  
D.F. Binns
Keyword(s):  
Steady State ◽  
Iterative Method ◽  
Temperature Rise ◽  
Buried Cables ◽  
Steady State Temperature ◽  
New Iterative Method

Test and Finite Element Simulation of Steady-State Temperature Field of Rolling Tire

2012 ◽  
Vol 236-237 ◽  
pp. 536-542 ◽  
Author(s):  
Xiang Lei Duan ◽  
Shu Guang Zuo ◽  
Yong Li ◽  
Chen Fei Jiang ◽  
Xue Liang Guo
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Steady State ◽  
Finite Element Simulation ◽  
Temperature Rise ◽  
Tire Pressure ◽  
Speed Factor ◽  
Element Simulation ◽  
Steady State Temperature ◽  
Single Factor Analysis

To analyze the steady-state temperature field, a three-factor orthogonal test was taken to study comprehensively how the load, speed and tire pressure can influence the tire temperature. The finite element simulation was carried out according to the uncoupled idea. Based on the single-factor analysis towards the speed factor, the actual convection coefficient of different boundaries was determined to calculate the steady-state temperature field at last. These analyses indicate that the tire temperature rise increase with the factor of load and speed, decrease with the increase of the initial tire pressure. The load has the biggest influence on the tire temperature rise, while the speed has the least. With the combination of steady-state temperature field and heat generation rate distribution, all these high-temperature regions can be explained clearly from the finite element perspective.

scholarly journals Simulation of Steady-State Temperature Rise of Electric Heating Field of Wireless Sensor Circuit Fault Current Trigger

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yinan Zhao ◽  
Jinwu Zhuang ◽  
Zhihao Ye ◽  
Zhiliang Qian ◽  
Fang Peng
Keyword(s):  
Steady State ◽  
Power Consumption ◽  
Temperature Rise ◽  
Electric Heating ◽  
Wireless Sensor ◽  
Test Results ◽  
Dynamic Adjustment ◽  
Received Signal Strength Indicator ◽  
Variable Gain ◽  
Steady State Temperature

This article analyzes the structure of the wireless sensor circuit, considering the balance of power consumption, integration, area, noise, etc., and adopts a radio frequency wireless sensor circuit with a low-IF structure. Through the analysis and comparison of traditional analog current trigger and digital current trigger structure, the feed-forward current trigger structure is selected, which is composed of received signal strength indicator (RSSI) and variable gain amplifier (VGA), which achieves low power consumption, fast stabilization time, and wide dynamic range design. The received signal strength indicator adopts the form of approximate logarithmic amplifier, five-stage double feedback loop structure, and realizes lower power consumption. In order to prevent the load current trigger from entering the speed saturation zone, a gain unit structure in which the superimposed current trigger is connected to the NMOS tube as the load is proposed. The test results show that the circuit has a good power consumption performance (1 mW) and at the same time 56.8 dB/m sensitivity. In this paper, through the analysis of the current trigger system and the analysis and comparison of the existing variable gain amplifiers, the variable gain amplifier structure composed of the folded wireless sensing unit and the index control unit is adopted. In order to reduce the power consumption of the circuit and increase the output swing, a structure in which the two-stage folding wireless sensor unit shares the controlled voltage-to-current part of the circuit is proposed. Aiming at the design requirements of the system, this article discussed in detail the architecture of the entire temperature measurement node and the design parameters of the chip and completed the overall architecture design of the chip. The simulation results of the steady-state temperature rise of the electric heating field show that the circuit has achieved an input dynamic adjustment range of more than 60 dB, the maximum power consumption is 1 mW, and the linearity error is less than 0.5 dB. The designed automatic gain control circuit is implemented in SMIC 0.18 cape CMOS process. The simulation results of the steady-state temperature rise of the electric heating field show that the circuit has a 56 dB input dynamic adjustment range within a linear error of 1.25 dB, and the time constant is 7.55 ms, and power consumption is 2.84 mW. Through the steady-state temperature rise simulation and test results of the electric heating field, the correctness of the design is verified and it meets the system requirements.

scholarly journals On the Steady-State Temperature Rise During Laser Heating of Multilayer Thin Films in Optical Pump–Probe Techniques

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Jeffrey L. Braun ◽  
Chester J. Szwejkowski ◽  
Ashutosh Giri ◽  
Patrick E. Hopkins
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Steady State ◽  
Temperature Rise ◽  
Laser Heating ◽  
Thermal Parameters ◽  
Heat Diffusion ◽  
Multilayer Thin Films ◽  
Steady State Temperature

In this study, we calculate the steady-state temperature rise that results from laser heating of multilayer thin films using the heat diffusion equation. For time- and frequency-domain thermoreflectance (TDTR and FDTR) that rely on modulated laser sources, we decouple the modulated and steady-state temperature profiles to understand the conditions needed to achieve a single temperature approximation throughout the experimental volume, allowing for the estimation of spatially invariant thermal parameters within this volume. We consider low thermal conductivity materials, including amorphous silicon dioxide (a-SiO2), polymers, and disordered C60, to demonstrate that often-used analytical expressions fail to capture this temperature rise under realistic experimental conditions, such as when a thin-film metal transducer is used or when pump and probe spot sizes are significantly different. To validate these findings and demonstrate a practical approach to simultaneously calculate the steady-state temperature and extract thermal parameters in TDTR, we present an iterative algorithm for obtaining the steady-state temperature rise and measure the thermal conductivity and thermal boundary conductance of a-SiO2 with a 65-nm gold thin film transducer. Furthermore, we discuss methods of heat dissipation to include the use of conductive substrates as well as the use of bidirectional heat flow geometries. Finally, we quantify the influence of the optical penetration depth (OPD) on the steady-state temperature rise to reveal that only when the OPD approaches the characteristic length of the temperature decay does it alter the temperature profile relative to the surface heating condition.

Steady-state heat sink analysis for two-terminal microwave oscillator devices with temperature dependent thermal conductivity

1993 ◽  
Vol 441 (1911) ◽  
pp. 181-189 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Steady State ◽  
Temperature Distribution ◽  
Temperature Rise ◽  
Heat Sink ◽  
Maximum Temperature ◽  
Microwave Oscillators ◽  
Steady State Temperature ◽  
Steady State Heat

A theoretical analysis to calculate the steady-state temperature distribution within a cylindrical heat sink configuration, where the thermal conductivity is dependent on the temperature, is outlined. The analysis applies to any heat sink arrangement that can be treated as one or more homogeneous solid cylinders mounted on a semi-infinite heat sink, where the heat flux incident on both faces of each cylinder is uniform over a given centralized circular region. The model is used to analyse the temperature distribution within the heat sink configurations used commonly to package two-terminal semiconductor devices that are operated as sources of electromagnetic radiation in microwave oscillators. Results are presented that show how the maximum temperature rise within commercially available heat sink packages, depends on the input heat flux and the dimensions and thermal conductivity of the materials. Furthermore, results that show how the temperature rise varies across the interfaces of given heat sink configurations, similar to those used commercially, are given also.

scholarly journals Identification of DC Thermal Steady-State Differential Inductance of Ferrite Power Inductors

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3854
Author(s):  
Salvatore Musumeci ◽  
Luigi Solimene ◽  
Carlo Stefano Ragusa
Keyword(s):  
Steady State ◽  
Input Voltage ◽  
Switching Frequency ◽  
Ohmic Losses ◽  
Steady State Temperature ◽  
Wide Range ◽  
Average Current ◽  
Power Inductors ◽  
Saturable Inductor ◽  
Thermal Steady State

In this paper, we propose a method for the identification of the differential inductance of saturable ferrite inductors adopted in DC–DC converters, considering the influence of the operating temperature. The inductor temperature rise is caused mainly by its losses, neglecting the heating contribution by the other components forming the converter layout. When the ohmic losses caused by the average current represent the principal portion of the inductor power losses, the steady-state temperature of the component can be related to the average current value. Under this assumption, usual for saturable inductors in DC–DC converters, the presented experimental setup and characterization method allow identifying a DC thermal steady-state differential inductance profile of a ferrite inductor. The curve is obtained from experimental measurements of the inductor voltage and current waveforms, at different average current values, that lead the component to operate from the linear region of the magnetization curve up to the saturation. The obtained inductance profile can be adopted to simulate the current waveform of a saturable inductor in a DC–DC converter, providing accurate results under a wide range of switching frequency, input voltage, duty cycle, and output current values.

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