摘要：The intermediate heat exchanger for enhancement heat transfer is the important equipment in the usage of nuclear energy. In the present work, heat transfer and entropy generation of an intermediate heat exchanger(IHX) in the accelerator driven subcritical system(ADS) are investigated experimentally. The variation of entropy generation number with performance parameters of the IHX is analyzed, and effects of inlet conditions of the IHX on entropy generation number and heat transfer are discussed. Compared with the results at two working conditions of the constant mass flow rates of liquid lead-bismuth eutectic(LBE) and helium gas, the total pumping power all tends to reduce with the decreasing entropy generation number, but the variations of the effectiveness, number of transfer units and thermal capacity rate ratio are inconsistent, and need to analyze respectively. With the increasing inlet mass flow rate or LBE inlet temperature, the entropy generation number increases and the heat transfer is enhanced, while the opposite trend occurs with the increasing helium gas inlet temperature. The further study is necessary for obtaining the optimized operation parameters of the IHX to minimize entropy generation and enhance heat transfer.

摘要：印刷电路板式换热器具有重量轻、体积小,紧凑度高和传热性能好等优点,非常适合用作舰用燃气轮机间冷器。本文针对舰用燃气轮机用的印刷电路板式间冷器进行了优化设计与分析,建立了印刷电路板式间冷器优化问题的数学模型,通过遗传算法的全局优化搜索能力分别以压降最小、质量最轻和紧凑度最高为目标进行间冷器结构参数优化,分析了固定热负荷条件下改变热侧工质质量流量对间冷器性能的影响。结果表明,单目标优化后的间冷器总压降减少了81.52%,总质量减轻了77.66%,紧凑度提高了69.10%。

摘要：为提高动力循环性能,将印刷电路板式换热器(printed circuit heat exchanger,PCHE)应用于间冷回热燃气轮机循环,采用数值模拟方法对变物性烟气和水在翼型通道内的流动换热性能展开研究。基于热力学第一定律与第二定律分析翅片横向和纵向间距对流动传热性能的影响,通过正交实验分析各个因素的影响权重并提出传热流动关联式。结果表明,两种工质下,换热器的综合性能随着纵向间距的增大而提高。当工质为水时,随着横向间距的减小,PCHE的综合性能提高,而当工质为烟气时,横向间距在2.4~3.6mm之间的综合性能最佳。传热强化和速度与温度梯度之间协同作用的增强密切相关,增大横向间距和纵向间距可以有效减少换热过程中的不可逆损失。不同横向和纵向间距会影响边界层的发展,进而影响换热器的流动换热性能。研究结果对在燃气轮机循环中翼型印刷电路板式换热器的优化设计具有一定的指导意义。

摘要：本文针对高温叶栅试验台的红外测温需求,设计了测温探头的防护结构,在尽量不干扰主流的前提下实现对测温探头的热防护与污染防护。通过CFD计算,分析了该结构设计的合理性。对冷却空气入口总压的影响进行分析,发现入口总压过小,会造成探头的高温烧蚀,总压过大,则会对主流产生较大干扰。最后对冷却水入口流速进行分析,结果表明,探头的冷却效果随流速增大而增强,当流速大于2 m/s时,冷却效果基本不随流速变化而变化。

摘要：在“3060双碳目标”背景下,能源高效输运与合理利用是实现碳中和的重要路径之一,而换热器在能量输运与转换中的作用至关重要。相较于传统换热器,微通道换热器在维持同等换热能力的同时,大幅减小了体积,极大提高了传热效率,在很多重要领域均有应用。超临界CO_(2)(S-CO_(2))发电系统、跨临界热泵和制冷系统等因环境友好和效率高等优势,在“双碳目标”背景下具有重要的应用前景。S-CO_(2)物性剧烈变化以及系统对高温高压的要求,对换热器设计、耐高温高压、高紧凑和高效率都提出巨大挑战,成为科学界和工业界研究的热点话题,且近几十年相关研究也取得了重要进展。为了全面回顾微通道换热器在S-CO_(2)系统中的研究进展,本文从S-CO_(2)的传热流动特性出发,分析了管内S-CO_(2)换热的影响因素与现有微通道换热器对S-CO_(2)系统的适用性。重点论述了印刷电路板式换热器(PCHE)不同结构形式及设计优化方法,最后讨论了PCHE的优化对整个S-CO_(2)系统的性能提升的影响。本文对S-CO_(2)微通道换热器进行了全面的论述,可为以CO_(2)或其它超临界工质为媒介的能源动力系统换热器的选型、设计和优化提供重要参考。

摘要：Fixed-bed reactors randomly packed with catalysts have many disadvantages that may adversely affect the desired chemical *** increasingly used monolithic reactor,in contrast,has many operational advantages;however,for a kinetically-controlled reaction,it does not contain sufficient catalyst to sustain the *** address the problems associated with both randomly packed-bed reactor and the monolithic reactor,a structured packed-bed reactor was proposed and mathematical models were built for randomly packed-bed reactor and structured packed-bed *** respective performances were compared when applied to the exothermic reaction of the isopropanol-acetone-hydrogen chemical heat pump *** results showed that the structured packed-bed reactor performed better in terms of pressure drop and heat transfer capacity,and had a lower radial temperature gradient,indicating that this reactor had a higher effective heat *** on the catalyst particle surfaces was more concentrated near the tube wall because a wall effect existed in the boundary layer around the particle-wall contact points.

摘要：可折叠笔记本电脑,采用柔性热管将CPU热量传导至显示屏背板,通过自然对流将热量带走,实现笔记本电脑CPU的温度控制。针对这一结构,采用Fluent软件建立笔记本电脑热管散热结构对应的物理模型,在自然对流条件下,改变柔性热管的弯折角度,研究不同弯折角度对散热性能的影响,分析不同条件下的温度变化曲线。设计显示屏背板作为模型主要散热结构。结果表明,在柔性热管恒定导热系数和随角度变化导热系数条件下,模型散热能力均随热管弯折角度减小而增大,同时,考虑了增加辐射后对模型散热能力的影响大小,考虑辐射后,总体散热趋势无较大变化。