An eddy-current method of checking for leaks of water (steam) in a liquid-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.

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Numerical Simulation of Non-Destructive Remote Field Eddy Current Testing of Rolled Metal Tubes

Herald of the Bauman Moscow State Technical University Series Mechanical Engineering ◽

10.18698/0236-3941-2019-5-46-55 ◽

2019 ◽

pp. 46-55

Author(s):

A.G. Efimov ◽

N.R. Kuzelev ◽

E.V. Martyanov ◽

B.M. Kanter ◽

A.E. Shubochkin

Keyword(s):

Numerical Simulation ◽

Eddy Current ◽

Current Method ◽

Eddy Current Testing ◽

Eddy Current Method ◽

Current Testing ◽

Advantages And Disadvantages ◽

Current Transducer ◽

Non Destructive ◽

Eddy Current Transducer

The first publications describing the physical principles of the non-destructive remote field eddy current testing method appeared about 30 years ago. This method allows to significantly expand the field of application of eddy current testing. However, due to the lack of a theoretical justification, this method did not get widespread use around the world. Domestic publications in this area are completely absent, and the descriptions given in few foreign publications often contradict each other. There are no results of full-scale simulation using numerical methods in available domestic and foreign sources. The distinctive feature of this method under consideration is the ability of detecting defects on the external (with respect to the eddy current transducer) side of the tested object, which is impossible for the classical eddy current method due to the limited eddy current penetration depth. The basics of the method were considered, the distinctive features were presented, and the advantages and disadvantages of remote field eddy current testing of metals were pointed out. A numerical simulation with the subsequent analysis of the obtained results has been carried out, the transducer design for remote field eddy current testing is given. The influence of various factors on the change in the added voltage of the signal coil of the eddy current transducer in the presence of a defect in the external wall of the tube was considered. Expressions that determine the optimal ratio of the diameters of the transducer and the tested product were obtained. The values of the test parameters and the limiting wall thickness of the tested ferromagnetic product were determined.

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