Effect of the Heat Dissipation System on Hard-Switching GaN-Based Power Converters for Energy Conversion

The design of a cooling system is critical in power converters based on wide-bandgap (WBG) semiconductors. The use of gallium nitride enhancement-mode high-electron-mobility transistors (GaN e-HEMTs) is particularly challenging due to their small size and high power capability. In this paper, we model, study and compare the different heat dissipation systems proposed for high power density GaN-based power converters. Two dissipation systems are analysed in detail: bottom-side dissipation using thermal vias and top-side dissipation using different thermal interface materials. The effectiveness of both dissipation techniques is analysed using MATLAB/Simulink and PLECS. Furthermore, the impact of the dissipation system on the parasitic elements of the converter is studied using advanced design systems (ADS). The experimental results of the GaN-based converters show the effectiveness of the analysed heat dissipation systems and how top-side cooled converters have the lowest parasitic inductance among the studied power converters.

Experimental Analysis on the Use of Counterflow Jets as a System for the Stabilization of the Spatial Hydraulic Jump

This study presents an investigation on the use of submerged counterflow jets as a means for stabilizing the spatial hydraulic jump occurring in abruptly expanding channels. The characteristics of the flow downstream from the stilling basin and the main parameters influencing the effectiveness of the device in improving flow uniformity and reducing scouring potential are examined in laboratory tests, under several geometric configurations and hydraulic boundary conditions. The position within the stilling basin and the jet density (i.e., the number of orifices issuing the counterflow jets) were found to be important parameters influencing the performance of the device. Overall, the results indicate that this dissipation system has promising capabilities in forcing the transition from supercritical to subcritical flow, by significantly shortening the protection length needed to limit the phenomena of instability associated with spatial hydraulic jumps.

Design of an Integrated Heat Dissipation Mechanism for a Quad Transmit Receive Module of Array Radar

A radar system requires a number of high-power components operating in a narrow and convection-free environment. This study aims to develop an integrated heat dissipation system that is suitable for the high-power electronic equipment of radar systems. The proposed heat dissipation mechanism integrates a fluid circulation-type cold plate with a quad transmit receive module. The finite element method in the COMSOL fluid–solid coupling heat transfer analysis software was used to analyze the heat dissipation performance of the cold plate in the proposed mechanism. The Taguchi method was adopted to optimize the cold plate design. The simulation and experimental results show that the proposed mechanism can control the temperature equalization and temperature of the system within the specified requirements. The practicality of the proposed mechanism was verified. The findings can serve as a reference for the design of high-power electronic equipment in a heat dissipation system.

SYNERGISTIC APPROACH TO THE CAPITAL ADAPTATION: CAPITAL AS A MULTIFUNCTIONAL DISSIPATION SYSTEM

The research subject of the paper is the process of capital adapting. The purpose of the article is to present capital as a multifunction dissipation system, which consists of the number of interconnected subsystems that operates being under the influence of destabilizing socio-economic factors. There is still no explicit definition of economic adaptation, and capital is not regarded as a set of tangible and intangible assets. Taking into account that the current operating environment, at both the macro and micro levels, may be characterized as unsustainable, and each system strives to organize itself to achieve the main objective, it is worth considering the process of adaptation, using a synergistic approach. This requires looking at the concept of capital as a multifunctional system, firstly, identifying which economic categories are made as subsystems of capital and which of them form capital, secondly, assessing potential areas of adaptation, thirdly, and identifying where adaptation can be targeted in the first place, fourthly. Determination of priority goals is the task of rapid financial analysis, using the results of strategic analysis it is possible to determine long-term goals of adaptation. Methodology. The article uses methods of empirical knowledge aimed at structuring approaches to the concepts of capital, their selection and analysis. Based on the empirical research, theoretical studies have been carried out. It was used such methods us analysis and synthesis, deduction, abstraction and generalization. The conceptual framework is based on the theoretical developments in various scientific fields that have studied capital, the enterprise, the economic system as an economic category, the concept of adaptation, synergies in the economy, and methods of strategic and financial analysis. By examining and analysing existing approaches to the listed issues, it has become possible to propose a definition of capital adaptation as a multifunctional dissipation system. As a result of the research, it became clear that for sustainable adaptation, it is advisable to use the tools of strategic management, and for instantaneous adaptation tools to ensure the economic and financial security of the enterprise. In the process of writing this research, it became clear that it was necessary to study issues related to the characteristics of subsystems, their assessment and analysis in order to make the adaptation process more multifaceted and effective.

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

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.