scholarly journals Research on a Simplified Model of an Aluminum Vapor Chamber in a Heat Dissipation System

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 35 ◽  
Author(s):  
Shuang Han ◽  
Lixin Yang ◽  
Zihao Tian ◽  
Xiaofei Yuan ◽  
Hongyan Lu
Keyword(s):  
Heat Dissipation ◽  
Cooling System ◽  
Thermal Characteristics ◽  
Development Trend ◽  
Simplified Model ◽  
Testing System ◽  
Vapor Chamber ◽  
Electronic Components ◽  
Simplified Models ◽  
Heat Transfer Limit

With the rapid increase of power densities of electronic components, the traditional heat dissipation method of air forced convection has reached a heat transfer limit. As efficient phase change heat exchangers, vapor chambers have become an important guarantee for the development of high-power electronic components. Aluminum vapor chambers have become the future development trend because they are more lightweight and less expensive. In order to study the suitable simplified model of the aluminum vapor chamber in the radiating system, the testing system is established to test the thermal characteristics of the vapor chamber. First, six simplified models of the vapor chamber are proposed. Then, the thermal characteristics of the simplified models are simulated by STAR CCM+ software. Next, the error of the thermal resistance of the simplified model and the real vapor chamber is analyzed. Finally, a most suitable simplified model is obtained in the cooling system.

Active cooling system for downhole electronics in high temperature environments

2021 ◽  
pp. 1-16
Author(s):  
Wei Minghui ◽  
Cai Wei ◽  
Xu Mingze ◽  
Deng Shuang
Keyword(s):  
High Temperature ◽  
Cooling System ◽  
Capillary Tube ◽  
Thermal Characteristics ◽  
Electric Circuit ◽  
Passive Cooling ◽  
Electronic Components ◽  
Active Cooling ◽  
Temperature Environment ◽  
High Temperature Environment

Abstract Downhole high temperature environment is an important factor affecting the performance of downhole instrument electronic system.At present, various active cooling technologies and passive cooling technologies have been proposed to reduce the temperature of downhole electric circuit system.However, passive cooling technologies can only provide limited cooling capacity for drilling tools under high temperature environment, and the duration of cooling is short, which can not meet the long-time drilling task.This paper presents an Active cooling system(ACS)for downhole electronics and the effects of different temperatures on the performance of electronic components are analyzed.The ACS mainly includes a micro supercharger, condenser tube, evaporation pipe, capillary tube and refrigerant.The theoretical analysis of heat transfer and refrigerant capacity in high temperature environment is carried out.The thermal characteristics of the ACS is evaluated experimentally.The results show that the temperature of electronic components can be reduced to below 163°C in the 200°C downhole environment and components.The geomagnetic field data measured by electronic components at room temperature, 200 °C and with ACS are compared.The results show that ACS can keep electronic components working normally.

Experimental Investigation on Flow and Thermal Characteristics of a Micro Phase-Change Cooling System With a Microgroove Evaporator

2006 ◽  
Author(s):  
Xuegong Hu ◽  
Dawei Tang
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
Cooling System ◽  
Thermal Sensitivity ◽  
Thermal Characteristics ◽  
Cooling Capacity ◽  
Input Power ◽  
Maximum Heat ◽  
Transportation Capacity

In this paper, a natural convection micro cooling system with a capillary microgroove evaporator is proposed. An experimental study on the characteristics of thermal resistance, pressure drop and heat transfer of the cooling system was carried out. Experimental results indicate that the liquid fill ratio has a significant influence on thermal resistance and heat transfer in the cooling system. Increasing system’s cooling capacity at higher input power depends on decreasing the thermal resistance between the outer surfaces of the condenser and ambient environment. Compared with a flat miniature heat pipe (FMHP) and a current fan-cooled radiator for CPU chip of Pentium IV, the present micro cooling system has a stronger heat dissipation capacity. Its best cooling performance at a surface temperature of heat source below 373K reaches 1.68×106W/m2 and the maximum heat transportation capacity is 131.8W. The novel kind of cooling system is suitable for remote cooling of those electronic parts with micro size, high power and thermal sensitivity.

scholarly journals The Progress of Composites with High Thermal Conductivity and Electromagnetic Shielding

2020 ◽  
Vol 1 (4) ◽  
pp. 18
Author(s):  
Houbao Liu ◽  
Renli Fu ◽  
Weisong Dong ◽  
Yingjie Song ◽  
Hao Zhang
Keyword(s):  
Thermal Conductivity ◽  
Composite Materials ◽  
Electromagnetic Interference ◽  
Heat Dissipation ◽  
Development Trend ◽  
Electromagnetic Shielding ◽  
High Thermal Conductivity ◽  
Heat Radiation ◽  
Electronic Components ◽  
High Package Density

<p>As electronic components develop toward high power, high package density, and device size miniaturization,  heat dissipation and electromagnetic interference between electronic components are becoming more and more serious. In order to solve the adverse elec  tromagnetic waves and heat radiation generated by electronic devices, people have high hopes for electronic packaging materials with high thermal conductivity and electromagnetic interference resistance. This paper summa  rizes the research status of high thermal conductivity composite materials and electromagnetic shielding composite materials. Finally, the latest research results of high thermal conductivity and electromagnetic shielding composites are introduced, and the future development trend of new materials for microelectronic packaging is prospected.</p>

scholarly journals Investigation on Thermal Characteristics of the Oil-Circulating Hydraulic Energy Storage System for Hybrid Mining Trucks

2021 ◽  
Vol 9 ◽  
Author(s):  
Tong Yi ◽  
Fei Ma ◽  
Chun Jin ◽  
Jichao Hong ◽  
Yanbo Liu
Keyword(s):  
Energy Storage ◽  
Heat Dissipation ◽  
Cooling System ◽  
Storage System ◽  
Thermal Characteristics ◽  
Energy Storage System ◽  
Thermal Design ◽  
Installation Space ◽  
Cooling Power ◽  
Transfer Model

The improved hydraulic energy storage system (IHESS) is a novel compact hydraulic ESS with only 10% of oil and 64.78% of installation space of the regular ones. However, its novel circulating structure and lightweight material result in poor heat dissipation. The thermodynamic and heat transfer model of IHESS with an oil-circulating layout is proposed. Based on the mining trucks’ dynamic model, thermal characteristics of IHESSs with different parameters under the actual and simplified working conditions are studied and the factors causing overheating are analyzed. Finally, a feasible thermal design is put forward, and its efficiency is analyzed. The simulation shows that more accumulators and higher recovery power lead to higher system temperature and vice versa. Under the standard simplified working condition at 40°C ambient temperature, the highest oil temperature reached is 93.13°C. About 90% of the generated heat is converted into the internal energy of nitrogen and oil. On this basis, by adopting an energy-saving passive cooling system with a cooling power of 6.68 kW, the highest temperature of the oil drops to 52.79°C and 28% of the generated heat is released through the cooling system.

scholarly journals A Machine Learning Solution for Data Center Thermal Characteristics Analysis

2020 ◽  
Author(s):  
marta chinnici ◽  
Anastasiia GRISHIna ◽  
Ah-Lian KOR ◽  
Eric Rondeau ◽  
jean philippe georges
Keyword(s):  
Machine Learning ◽  
Energy Efficiency ◽  
Air Temperature ◽  
Data Center ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Cooling System ◽  
Thermal Characteristics ◽  
Ambient Air ◽  
Characteristics Analysis

Energy efficiency of Data Center (DC) operations heavily relies on IT and cooling systems performance. A reliable and efficient cooling system is necessary to produce a persistent flow of cold air to cool servers that are subjected to constantly increasing computational load due to the advent of IoT- enabled smart systems. Consequently, increased demand for computing power will bring about increased waste heat dissipation in data centers. In order to bring about a DC energy efficiency, it is imperative to explore the thermal characteristics analysis of an IT room (due to waste heat). This work encompasses the employment of an unsupervised machine learning modelling technique for uncovering weaknesses of the DC cooling system based on real DC monitoring thermal data. The findings of the analysis result in the identification of areas for energy efficiency improvement that will feed into DC recommendations. The methodology employed for this research includes statistical analysis of IT room thermal characteristics, and the identification of individual servers that frequently occur in the hotspot zones. A critical analysis has been conducted on available big dataset of ambient air temperature in the hot aisle of ENEA Portici CRESCO6 computing cluster. Clustering techniques have been used for hotspots localization as well as categorization of nodes based on surrounding air temperature ranges. The principles and approaches covered in this work are replicable for energy efficiency evaluation of any DC and thus, foster transferability. This work showcases applicability of best practices and guidelines in the context of a real commercial DC that transcends the set of existing metrics for DC energy efficiency assessment.

scholarly journals Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3634
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn
Keyword(s):  
Mass Transfer ◽  
Phase Change ◽  
Heat Dissipation ◽  
Cooling System ◽  
Numerical Study ◽  
Relaxation Parameter ◽  
Phase Changes ◽  
Transfer Time ◽  
Two Phase ◽  
Time Relaxation

With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation rc depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation re = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient re should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.

scholarly journals Design and thermal characteristic analysis of motorized spindle cooling system

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110208
Author(s):  
Yuan Zhang ◽  
Lifeng Wang ◽  
Yaodong Zhang ◽  
Yongde Zhang
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Thermal Deformation ◽  
Cooling System ◽  
Thermal Characteristic ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Characteristic Analysis ◽  
Motorized Spindle ◽  
Experiment And Simulation

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

A simplified model of Passive Containment Cooling System in a CFD code

2013 ◽  
Vol 262 ◽  
pp. 579-588 ◽  
Author(s):  
X.W. Jiang ◽  
E. Studer ◽  
S. Kudriakov
Keyword(s):  
Cooling System ◽  
Simplified Model

Heat dissipation system based on electromagnetic driven rotational flow of liquid metal coolant

2021 ◽  
pp. 1-14
Author(s):  
Lei Wang ◽  
Xudong Zhang ◽  
Dr. Jing Liu ◽  
Yixin Zhou
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Cooling System ◽  
Electric Heater ◽  
Power Relationship ◽  
Rotational Flow ◽  
Large Power ◽  
Dissipation System

Abstract Liquid metal owns the highest thermal conductivity among all the currently available fluid materials. This property enables it to be a powerful coolant for the thermal management of large power device or high flux chip. In this paper, a high-efficiency heat dissipation system based on the electromagnetic driven rotational flow of liquid metal was demonstrated. The velocity distribution of the liquid metal was theoretically analyzed and numerically simulated. The results showed that the velocity was distributed unevenly along longitudinal section and the maximum velocity appears near the anode. On the temperature distribution profile of the heat dissipation system, the temperature on the electric heater side was much higher than the other regions and the role of the rotated liquid metal was to homogenize the temperature of the system. In addition, the thermal resistance model of the experimental device was established, and several relationships such as thermal resistance-power curve were experimentally measured. The heating power could be determined from the temperature-power relationship graph once the maximum control temperature was given. The heat dissipation method introduced in the paper provides a novel way for fabricating compact chip cooling system.

scholarly journals Effect of perspired moisture and material properties on evaporative cooling and thermal protection of the clothed human body exposed to radiant heat

2018 ◽  
Vol 89 (18) ◽  
pp. 3663-3676 ◽  
Author(s):  
Manhao Guan ◽  
Agnes Psikuta ◽  
Martin Camenzind ◽  
Jun Li ◽  
Sumit Mandal ◽  
...  
Keyword(s):  
Human Body ◽  
Material Properties ◽  
Heat Dissipation ◽  
Thermal Protection ◽  
Evaporative Cooling ◽  
Thermal Characteristics ◽  
Radiant Heat ◽  
Physiological Effect ◽  
Heat Gain ◽  
Active Liquid

Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain for hydrophobic materials. In addition to fabric thermal resistance ( Rct) and evaporative resistance ( Ret), material hydrophilicity and hydrophobicity, emissivity and thickness are important when assessing metabolic heat dissipation and radiant heat gain with profuse sweating under radiant heat. The results provide experimental evidence that Rct and Ret, the general indicators of the clothing thermo-physiological effect, have limitations in characterizing thermal comfort and heat strain during active liquid sweating in radiant heat. This paper offers a more complete insight into clothing thermal characteristics and human thermal behaviors under radiant heat, contributing to the accurate evaluation of thermal stress for occupational and general individuals.

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