共查询到16条相似文献,搜索用时 171 毫秒
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双向进气型脉管制冷机的线性理论分析 总被引:1,自引:0,他引:1
采用线性模型对双向进气型脉管制冷机的性能进行了分析.得到了通过回热器的焓流、质量流量及脉管冷端压力和流量相位差的代数计算公式.详细分析了工作频率对脉管制冷机制冷量与COP的影响,并对额定输入压力振幅和额定输入功率两种工况分别进行了优化分析.所得结果与其它文献完全一致. 相似文献
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《真空与低温》2015,(4)
回热器是回热式低温制冷机的关键部件,其性能优劣对制冷机的性能有决定性影响,因此研究回热器性能的影响因素、优化回热器结构参数非常重要。基于经典的热力学和流体力学原理,引入了表征回热器内部交变流动换热特性的两个相似准则数即瓦伦西数(Va)和交变流贝克利数(Pe_w),并提出分层丝网回热器结构。通过用REGEN3.3模拟分层丝网回热器,得到结果:分层填充方式对回热器的性能起到了很重要的作用,适当地分层填充可以提高性能系数COP(净冷量与热端PV功之比),验证了本文对回热器的分析。优化结果表明,Case.5的填充方式是最好的,它可以在制冷温度为45 K,输入功61.6 W时提供2.8 W制冷量。 相似文献
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本文建立了分置式斯特林制冷机的优化设计模型,讨论了分置式制冷机的特点、优化设计及其数学模型中的特殊问题,考虑了制冷机中存在的主要冷量损失和直接功耗损失,选用了制冷机的12个主要结构和运行参数作为设计变量。实例计算中得到的优化结果与实验统计数据吻合较好。 相似文献
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The work proposes a simple and feasible calculation method--network model method to calculate temperature differences generated in thermo-driven thermoacoustic refrigerator (TAR). The theoretical calculation model is first built. The network model is given and used to make numerical calculations under different conditions including heat-pump stack positions in TAR, different oscillating pressure ratios (PR), plate spacings and different stack geometries. Theoretically calculated results show that the former two factors make significant influence on temperature differences, the influence of stack spacing on temperature difference has relation with PR, and cooling effect of pin-array stack is superior to that of parallel plate stack under other same conditions. Furthermore, theoretically calculated results and experimentally measured data are in good agreement at small acoustic pressure amplitude. 相似文献
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One of the most significant considerations in the design of a heat sink is thermal
management due to increasing thermal flux and miniature in size. These heat sinks utilize
plate or pin fins depending upon the required heat dissipation rate. They are designed to
optimize overall performance. Elliptical pin fin heat sinks enhance heat transfer rates and
reduce the pumping power. In this study, the Firefly Algorithm is implemented to optimize
heat sinks with elliptical pin-fins. The pin-fins are arranged in an inline fashion. The natureinspired metaheuristic algorithm performs powerfully and efficiently in solving numerical
global optimization problems. Based on mass, energy, and entropy balance, three models
are developed for thermal resistance, hydraulic resistance, and entropy generation rate in
the heat sink. The major axis is used as the characteristic length, and the maximum velocity
is used as the reference velocity. The entropy generation rate comprises the combined effect
of thermal resistance and pressure drop. The total EGR is minimized by utilizing the firefly
algorithm. The optimization model utilizes analytical/empirical correlations for the heat
transfer coefficients and friction factors. It is shown that both thermal resistance and
pressure drop can be simultaneously optimized using this algorithm. It is demonstrated that
the performance of FFA is much better than PPA. 相似文献
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利用实验数据,分析与研究振动场振动参数对聚合物挤出制品质量的影响,对聚合物挤出制品的熔体流动速率,微晶结构,拉伸强度等主要性能质量指标,建立以振动频率为主要控制变量的神经网络模型,并引入信息分配模型,探讨了一个网络输入节点下神经网络学习样本的特征提取与优化。实验结果表明,经过信息预处理的学习样本,可以使网络有更好的收敛效果。 相似文献
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Mehdi Bahiraei Saeed Heshmatian Marjan Goodarzi Hossein Moayedi 《Advanced Powder Technology》2019,30(11):2503-2516
This research aims to study the thermal and hydraulic attributes as well as energy efficiency of a new ecofriendly nanofluid including functionalized graphene nanoplatelets in a mini heat sink with three different pin fins. The circular, triangular and drop-shaped pin fins are investigated and compared with each other. The effects of nanoparticle fraction and flow velocity on the thermal resistance, temperature uniformity, convective heat transfer coefficient, maximum surface temperature, average surface temperature, pressure loss and pumping power are assessed. Increasing the concentration or velocity reduces the temperature on the heated wall, and also improves the temperature distribution uniformity. At both constant velocity and invariant pumping power, the heat sink fitted with the circular pin fins leads to the best performance while that equipped with the triangular pin fins results in the worst efficiency. In addition, the Figure of Merit (FoM) is greater than 1 for all conditions, which proves that the nanoparticle suspension possesses a greater merit to be employed as the coolant in the heat sinks compared to the base fluid. 相似文献