Experimental Investigation of Heat Transfer in Coated Microchannels for MEMS Applications

2015 ◽  
Vol 813-814 ◽  
pp. 782-786
Author(s):  
C. Anbumeenakshi ◽  
M.R. Thansekhar ◽  
M. Satheeshkumar ◽  
R. Vishnu Gayathri
Keyword(s):  
Heat Transfer ◽  
Electronics Cooling ◽  
High Heat ◽  
Thermal Design ◽  
Heat Transfer Characteristics ◽  
Rectangular Microchannel ◽  
Transfer Characteristics ◽  
Viable Solution ◽  
Cooling Devices ◽  
Microchannel Cooling

The microchannel cooling technique appears to be a viable solution to high heat rejection requirements of today’s high-power electronic devices. The thermal design of the small electronics cooling devices is a key issue that needs to be optimized in order to keep the system temperatures at certain levels. Thus the need of microchannel became vital. This present work investigates the experimental work conducted in a coated rectangular microchannel heat sink of hydraulic diameter of 0.763 mm for a heat input of 250 to 1020 Watt with water to study the heat transfer characteristics with two types of header arrangement such as rectangular header and trapezoidal header. The header plays a significant role in distributing the water in to the channels. The uniform distribution of water leads to uniform heat transfer in microchannels. From the experimental results carried with two types of header arrangements, it was found that coated rectangular microchannel with trapezoidal header gives better heat transfer characteristics for the range of heat inputs.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2019 ◽  
Author(s):  
Ganesh Guggilla ◽  
Arvind Pattamatta ◽  
Ramesh Narayanaswamy
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Heated Surface ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

High heat flux flow boiling in silicon multi-microchannels – Part I: Heat transfer characteristics of refrigerant R236fa

2008 ◽  
Vol 51 (21-22) ◽  
pp. 5400-5414 ◽  
Author(s):  
Bruno Agostini ◽  
John Richard Thome ◽  
Matteo Fabbri ◽  
Bruno Michel ◽  
Daniele Calmi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Heat Transfer Characteristics ◽  
Flux Flow ◽  
Transfer Characteristics

scholarly journals Thermal Calculation and Experimental Investigation of Electric Heating and Solid Thermal Storage System

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5241
Author(s):  
Haichuan Zhao ◽  
Ning Yan ◽  
Zuoxia Xing ◽  
Lei Chen ◽  
Libing Jiang
Keyword(s):  
Heat Transfer ◽  
Calculation Method ◽  
Heat Storage ◽  
Storage System ◽  
Electric Heating ◽  
Thermal Storage ◽  
Thermal Design ◽  
Thermal Calculation ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Electric heating and solid thermal storage systems (EHSTSSs) are widely used in clean district heating and to flexibly adjust combined heat and power (CHP) units. They represent an effective way to utilize renewable energy. Aiming at the thermal design calculation and experimental verification of EHSTSS, the thermal calculation and the heat transfer characteristics of an EHSTSS are investigated in this paper. Firstly, a thermal calculation method for the EHSTSS is proposed. The calculation flow and calculation method for key parameters of the heating system, heat storage system, heat exchange system and fan-circulating system in the EHSTSS are studied. Then, the instantaneous heat transfer characteristics of the thermal storage system (TSS) in the EHSTSS are analyzed, and the heat transfer process of ESS is simulated by the FLUENT 15 software. The uniform temperature distribution in the heat storage and release process of the TSS verifies the good heat transfer characteristics of the EHSTSS. Finally, an EHSTSS test verification platform is built and the historical operation data of the EHSTSS is analyzed. During the heating and release thermal process, the maximum temperature standard deviation of each temperature measurement point is 28.3 °C and 59 °C, respectively. The correctness of the thermal calculation of the EHSTSS is thus verified.

Heat Transfer Characteristics of Subcooled Water Flow Boiling in Circular Channels With Non-Uniform Heating Fluxes

2016 ◽  
Author(s):  
Ge Zhu ◽  
Qincheng Bi ◽  
Jianguo Yan ◽  
Qizheng Yuan ◽  
Haicai Lv ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Flow ◽  
High Heat ◽  
Heat Fluxes ◽  
Dominant Factor ◽  
Uniform Heating ◽  
Heat Transfer Characteristics ◽  
Subcooled Water ◽  
Transfer Characteristics ◽  
Twisted Tapes

Experiments of heat transfer characteristics of subcooled water flowing in vertical circular channels, which were off-center in rectangular blocks, were carried out under high heat fluxes up to the ITER requirements. The heating flux distributions of the channels were non-uniform in the circumferential direction, which were obtained by electrically heating the blocks directly. Two types of channels were used: smooth channel and twisted tapes channel. The surface temperature of the rectangular blocks was measured by infrared camera and thermocouples. Effect of the system pressure, mass flow rate, inlet subcooling, and equivalent heat fluxes on heat transfer were all investigated. The main attention was paid to the subcooled water heat transfer under non-uniform heating flux, and the effect of twisted tapes. Results show that subcooled boiling is more likely to become the dominant factor under the conditions of lower mass flow rates, higher heat fluxes and lower system pressures. Twisted tapes can enhance the heat transfer, which is more evident in high heat fluxes. The temperature fields in the block were calculated with a Computational Fluid Dynamics (CFD) method to obtain, which were consistent with the experimental results.

Experimental and Numerical Investigation of Heat Transfer Characteristics of Inline and Staggered Arrays of Impinging Jets

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Yunfei Xing ◽  
Sebastian Spring ◽  
Bernhard Weigand
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Local Heat Transfer ◽  
Impinging Jets ◽  
Design Tool ◽  
Thermal Design ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Transfer Characteristics ◽  
Plate Spacing

A combined experimental and numerical investigation of the heat transfer characteristics within an array of impinging jets has been conducted. The experiments were carried out in a perspex model using a transient liquid crystal method. Local jet temperatures were measured at several positions on the impingement plate to account for an exact evaluation of the heat transfer coefficient. The effects of the variation in different impingement patterns, jet-to-plate spacing, crossflow schemes, and jet Reynolds number on the distribution of the local Nusselt number and the related pressure loss were investigated experimentally. In addition to the measurements, a numerical investigation was conducted. The motivation was to evaluate whether computational fluid dynamics (CFD) can be used as an engineering design tool in the optimization of multijet impingement configurations. This required, as a first step, a validation of the numerical results. For the present configuration, this was achieved assessing the degree of accuracy to which the measured heat transfer rates could be computed. The overall agreement was very good and even local heat transfer coefficients were predicted at high accuracy. The numerical investigation showed that state-of-the-art CFD codes can be used as suitable means in the thermal design process of such configurations.

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