Numerical Evaluation on the Cooling Capability of MEMS Based Liquid Metal Cooling Device Used in Harsh Environment

2007 ◽  
Author(s):  
Zhong-Shan Deng ◽  
Jing Liu ◽  
Yi-Xin Zhou
Keyword(s):  
Thermal Management ◽  
Numerical Evaluation ◽  
High Capacity ◽  
Small Scale ◽  
Harsh Environment ◽  
Electronic Components ◽  
Cooling Device ◽  
Sensors And Actuators ◽  
Micro Systems ◽  
Liquid Metal Cooling

The thermal management of the increasing fast chips has been a major concern in packaging of micro/nano systems [1]. These chips are squeezing into tighter and tighter spaces with no enough places for heat to dissipate. It is expected that heat flux levels in excess of 100 W/cm2 for commercial electronics and over 1000 W/cm2 for selected military high power electronics will soon become a realistic challenge to overcome. Meanwhile, high-capacity cooling options remain limited for many small-scale applications such as micro-systems, sensors and actuators, and micro/nano electronic components.

Recent Advancement on Liquid Metal Cooling for Thermal Management of Computer Chip

2010 ◽  
Author(s):  
Jing Liu ◽  
Yue-Guang Deng ◽  
Zhong-Shan Deng
Keyword(s):  
Liquid Metal ◽  
Thermal Management ◽  
New Technology ◽  
Air Cooling ◽  
Liquid Metal Coolant ◽  
Cooling Device ◽  
Chip Cooling ◽  
Cooling Method ◽  
Liquid Metal Cooling ◽  
Metal Coolant

Efficient cooling of a high performance computer chip has been an extremely important however becoming more and more tough issue. The recently invented liquid metal cooling method is expected to pave the way for high flux heat dissipation which is hard to tackle otherwise by many existing conventional cooling strategies. However, as a new thermal management method, its application also raised quite a few challenging fundamental and practical issues for solving. To illustrate the development of the new technology, this talk is dedicated to present an overview on the latest advancements made in the author’s lab in developing the new generation chip cooling device based on the liquid metal coolant with melting point around room temperature. The designing and optimization of the cooling device and component will be discussed. Several major barriers to prevent the new method from practical application such as erosion between liquid metal coolant and its substrate material will be outlined with good solutions clarified. Performance comparison between the new chip cooling method with commercially available products with highest quality such as air cooling, water cooling and heat pipe cooling devices were evaluated. Typical examples of using liquid metal cooling for the thermal management of a real PC or even super computer will be demonstrated. Further, miniaturizations on the prototype device by extending it as a MEMS cooling device or mini/micro channel liquid metal cooling device will also be explained. Along with the development of the hardware, some fundamental heat transfer issues in characterizing the liquid metal cooling device will be discussed through numerical or analytical model. Future challenging issues in pushing the new technology into large scale practices will be raised. From all the outputs obtained so far, it can be clearly seen that the new cooling strategy will find very promising and significant applications in a wide variety of engineering situations whenever thermal managements or heat transport are needed.

Design of a Self-Driven Liquid Metal Cooling Device for Heat Dissipation of Hot Chips in a Closed Cabinet

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Peipei Li ◽  
Jing Liu ◽  
Yixin Zhou
Keyword(s):  
Liquid Metal ◽  
Thermal Management ◽  
Horizontal Plane ◽  
Heat Dissipation ◽  
Hot Spot ◽  
Cooling Device ◽  
Large Power ◽  
Convective Thermal ◽  
The One ◽  
Liquid Metal Cooling

Tremendous attentions have been focused on thermal management to control the temperature of many advanced integrated electronic devices. The liquid metal cooling has recently been validated as a highly effective method to dissipate heat from hot chips. In this study, a practical design and implementation of a buoyancy effect driven liquid metal cooling device for the automatic thermal management of hot chips in a closed cabinet were demonstrated. The principles, especially the theory for convective thermal resistance of liquid metal cooling was provided for guiding optimization of the device. A model prototype was then fabricated and tested. Experiments were performed when two simulated hot chips in the closed cabinet worked at different heat loads and different angles with the horizontal plane. It was shown that for the one chip case, the cooling device could maintain the chip temperature to below 85.1 °C at the ambient temperature 20 °C when the heat load was about 122 W. The cooling performance of the device could achieve better when the angle between the cabinet and the horizontal plane varied from 0 °C to 90 °C. With two chips working simultaneously, both chips had close temperature and hot spot did not appear easily when subject to large power, which will help reduce thermal stress and enhance reliability of the system. The practical value of the self-driven liquid metal cooling device is rather evident. Given its reliability, simplicity, and efficiency, such device can possibly be used for heat dissipation of multichip in closed space in the future.

scholarly journals Stress-driven two-phase integral elasticity for Timoshenko curved beams

2021 ◽  
pp. 239779142199051
Author(s):  
Marzia S Vaccaro ◽  
Francesco P Pinnola ◽  
Francesco Marotti de Sciarra ◽  
Marko Canadija ◽  
Raffaele Barretta
Keyword(s):  
Solution Procedure ◽  
Small Scale ◽  
Curved Beams ◽  
Sensors And Actuators ◽  
Two Phase ◽  
Design And Optimization ◽  
Local Responses ◽  
Size Dependent ◽  
Classical Boundary ◽  
Phase Integral

In this research, the size-dependent static behaviour of elastic curved stubby beams is investigated by Timoshenko kinematics. Stress-driven two-phase integral elasticity is adopted to model size effects which soften or stiffen classical local responses. The corresponding governing equations of nonlocal elasticity are established and discussed, non-classical boundary conditions are detected and an effective coordinate-free solution procedure is proposed. The presented mixture approach is elucidated by solving simple curved small-scale beams of current interest in Nanotechnology. The contributed results could be useful for design and optimization of modern sensors and actuators.

Experimental and Numerical Evaluation of Small-Scale Cryosurgery Using Ultrafine Cryoprobe

2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Numerical Evaluation ◽  
Small Scale ◽  
Outer Diameter ◽  
Cooling Performance ◽  
The Heat Transfer Coefficient

The objective of this work is to experimentally and numerically evaluate small-scale cryosurgery using an ultrafine cryoprobe. The outer diameter (OD) of the cryoprobe was 550 μm. The cooling performance of the cryoprobe was tested with a freezing experiment using hydrogel at 37 °C. As a result of 1 min of cooling, the surface temperature of the cryoprobe reached −35 °C and the radius of the frozen region was 2 mm. To evaluate the temperature distribution, a numerical simulation was conducted. The temperature distribution in the frozen region and the heat transfer coefficient was discussed.

Natural vibrations of micro beams with nonrigid supports

2016 ◽  
Vol 23 (19) ◽  
pp. 3233-3246 ◽  
Author(s):  
Diana V Bambill ◽  
Graciela I Guerrero ◽  
Daniel H Felix
Keyword(s):  
Boundary Conditions ◽  
Couple Stress Theory ◽  
Continuum Theory ◽  
Modified Couple Stress Theory ◽  
Free Vibrations ◽  
Small Scale ◽  
Stress Theory ◽  
Edge Conditions ◽  
Micro Systems ◽  
Micro Structures

The present study aims to provide some new information for the design of micro systems. It deals with free vibrations of Bernoulli–Euler micro beams with nonrigid supports. The study is based on the formulation of the modified couple stress theory. This theory is a nonclassical continuum theory that allows one to capture the small-scale size effects in the vibrational behavior of micro structures. More realistic boundary conditions are represented with elastic edge conditions. The effect of Poisson’s ratio on the micro beam characteristics is also analyzed. The present results revealed that the characterization of real boundary conditions is much more important for micro beams than for macro beams, and this is an assessment that cannot be ignored.

Design of an LTCC Structure for a Micro-Ceramic Combustor

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000288-000293
Author(s):  
Darko Belavic ◽  
Marko Hrovat ◽  
Gregor Dolanc ◽  
Kostja Makarovic ◽  
Marina Santo Zarnik ◽  
...  
Keyword(s):  
High Pressures ◽  
Three Dimensional ◽  
Ceramic Technology ◽  
Electronic Components ◽  
Buried Structures ◽  
Flow Rates ◽  
Points Of View ◽  
Micro Systems ◽  
Micro Combustor ◽  
Harsh Conditions

Advanced micro- or macro-systems are in some cases made with multilayer ceramic technology. Low-Temperature Co-fired Ceramic (LTCC) technology is considered as one of the more suitable technologies for the fabrication of ceramic micro-systems that integrate screen-printed, thick-film electronic components as well as three-dimensional buried structures, for example, cavities and channels. One of the applications is a ceramic combustor. The chemical energy of the fuel is converted into thermal energy in a chemical micro-combustor through a burning process, while the accompanying high temperatures and, frequently, high pressures impose harsh conditions on the combustor structure. Therefore, the combustor must be carefully designed not only from the functional, thermal and chemical points of view, but also with respect to the mechanical strength. The combustor device was prepared by laminating of Du Pont 951PX LTCC green tapes. The fabricated 3D LTCC structures with buried cavities and channels including two inlets (for fuel and air), the evaporator for the fuel, the mixing system of the channels (for mixing the evaporated fuel and air), the distribution channels and eight microburners were realized. The main parts are eight micro-burners realized as buried cavities. In the burners a platinum-based catalyst was deposited to assist the oxidation, i.e., the burning, of the methanol with the air. Thickfilm, platinum-based heaters and temperature sensors are incorporated within the structure. The device was tested with different flow rates of liquid methanol (1 ml/h to 5 ml/h) and air (7 l/h to 15 l/h). The obtained temperatures were between 250°C and 450°C.

Thermal Design and Testing of a Passive Helmet Heat Exchanger With Additively Manufactured Components

2018 ◽  
Author(s):  
Kailyn Cage ◽  
Monifa Vaughn-Cooke ◽  
Mark Fuge ◽  
Briana Lucero ◽  
Dusan Spernjak ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Thermal Management ◽  
Heat Pipes ◽  
Thermal Design ◽  
Analytical Models ◽  
Small Scale ◽  
Dimensional System ◽  
Concept Design ◽  
Environmental Chamber

Additive manufacturing (AM) processes allow for complex geometries to be developed in a cost- and time-efficient manner in small-scale productions. The unique functionality of AM offers an ideal collaboration between specific applications of human variability and thermal management. This research investigates the intersection of AM, human variability and thermal management in the development of a military helmet heat exchanger. A primary aim of this research was to establish the effectiveness of AM components in thermal applications based on material composition. Using additively manufactured heat pipe holders, the thermal properties of a passive evaporative cooler are tested for performance capability with various heat pipes over two environmental conditions. This study conducted a proof-of-concept design for a passive helmet heat exchanger, incorporating AM components as both the heat pipe holders and the cushioning material targeting internal head temperatures of ≤ 35°C. Copper heat pipes from 3 manufactures with three lengths were analytically simulated and experimentally tested for their effectiveness in the helmet design. A total of 12 heat pipes were tested with 2 heat pipes per holder in a lateral configuration inside a thermal environmental chamber. Two 25-hour tests in an environmental chamber were conducted evaluating temperature (25°C, 45°C) and relative humidity (25%, 50%) for the six types of heat pipes and compared against the analytical models of the helmet heat exchangers. Many of the heat pipes tested were good conduits for moving the heat from the head to the evaporative wicking material. All heat pipes had Coefficients of Performance under 3.5 when tested with the lateral system. Comparisons of the analytical and experimental models show the need for the design to incorporate a re-wetting reservoir. This work on a 2-dimensional system establishes the basis for design improvements and integration of the heat pipes and additively manufactured parts with a 3-dimensional helmet.

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