汽车发动机紧凑型冷却系统的研究

应用流体仿真模拟软件建立冷凝器、散热器和风扇等主要零部件的冷却系统三维仿真模型,结合仿真分析可以直观地观察速度场和温度场的变化及其影响因素,最后再通过试验验证上述仿真模型。结果表明:仿真结果与试验数据趋势吻合良好,该仿真模型可以有效地对紧凑型冷却系统的流动与传热性能进行研究,有利于缩短设计周期和减少设计成本。

Compact Thermosyphon Heat Exchanger for Power Electronics Cooling

The heat losses density in power electronics products follows an ever increasing trend. Nowadays they reach 200 W/cmz at chip level and 50 W/cm2 at heatsink base level. Water cooling is the most effective cooling method but unfortunately water is often undesired due to high voltages or costumer requirements. Two-phase cooling is a promising technology for electronics cooling. It allows using dielectric fluids in passive systems and still benefits from very high heat transfer coefficients. Thermosyphons are a particularly interesting technology in the field of power electronics because it is entirely passive and a simple equipment. ABB has developed a compact thermosyphon heat exchanger based on automotive technology, which uses numerous multi-port extruded tubes with capillary sized channels disposed in parallel and brazed to a heated base plate in order to achieve the desired compactness. The experimental performances of this novel power electronics cooling system are presented with R134a as a working fluid. The influence of several parameters on the performances was studied experimentally： coolant flow rate, coolant temperature, heat load and fluid filling.

热轧带钢生产先进的改造理念和技术

近年来投资的快速回报已经变得越来越重要。现在对于工程公司的挑战不仅局限于装备的发展水平和技术的竞争，而且最短的交付使用时间、最短的停产周期及快速正常运行也均为决定性的因素。工厂装备改造理念是必须能够保证更大的生产适应性。