共查询到20条相似文献,搜索用时 589 毫秒
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强光眩目装置的发热量大、结构复杂,首先对其内部结构进行散热设计,改善内部气流通道;其次对多种散热鳍片进行仿真分析,获取最优的散热鳍片布局形式和鳍片高度、厚度、数量、间距等技术参数,再通过理论分析计算得出强制风冷所需的空气流量,并根据空气流量选取合适的风机,可在一定程度上改善强光眩目装置的散热效果。 相似文献
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提出了一种应用于船舶柴油机排气管道上的嵌入式鳍片热电转换系统,并对其结构进行了新型设计;建立排气管道热电转换系统三维模型,分析废气管道中嵌入式热电模组在不同条件下的流场、温度场以及电场分布特性;搭建排气管道热电转换系统模拟试验装置,验证数值计算结果准确性。结果表明:数值计算结果与实验结果相吻合,最大发电功率误差均在5%以内,嵌入式鳍片模组的发电功率比无嵌入式鳍片模组的发电功率提升了约3.2倍;系统设计过程中,需同时考虑鳍片高度、鳍片数量与流场特性、泵功率、净发电功率之间的关系,使其达到最大发电量,该装置通过鳍片增加传热面积,降低热阻,进而提升热电模组发电性能。 相似文献
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以平直翅片管式换热器为研究对象,采用计算流体力学(CFD)方法进行建模和模拟计算,通过对正交试验结果进行极差和方差的分析,综合考虑了翅片厚度、翅片间距、管横向间距和管纵向间距对努赛尔数Nu和阻力系数的影响程度和显著水平,并结合综合性能评价指标进行分析,结果显示:翅片厚度、翅片间距和管横向间距对换热器的传热性能影响显著,管纵向间距对换热器的传热性能无显著影响。当翅片厚度为2mm,翅片间距为9mm,管横向间距为65mm,纵向间距为115mm时传热性能最佳。 相似文献
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用分布参数法建立数学模型,对CO2冷风机在高温工况下进行仿真模拟计算。分析计算了管内制冷剂侧的传热特性,以及管间距与翅片间距对换热系数和压降的影响。结果表明,由于随着干度的增加,管内CO2流型不断发生变化,管内侧换热系数和压降也随之变化。在设计冷风机时,应综合考虑翅片间距与管间距对冷风机总换热系数及空气侧压降的影响。 相似文献
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Hakan Demir Ahmet Koyun Ş. Özgür Atayılmaz Özden Ağra Ahmet Selim Dalkılıç 《Journal of Mechanical Science and Technology》2013,27(8):2497-2506
Heat transfer from finned pipes buried in the soil has been investigated using experimental, analytical and numerical techniques. The experimental setup consists of a ground source heat pump system and two separate ground heat exchangers. Constant surface temperature approach based on Carslaw and Jaeger’s theory study was used for calculating the heat transfer from the pipes analytically. The problem was modeled and solved using a CFD program numerically. Effects of the fin number, fin length and simulation time on the heat transfer rate have been investigated and compared with bare tube. A modified analytical formula was also proposed for finned pipes in this study. 相似文献
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叠片式翅片管空气冷却器是一种高效、紧凑的空气换热高备。对新开发的第二代波纹型叠片进行了传热及阻力性能的测试,获得了一系列试验工况下的传热和管外空气流动阻力数据,通过计算得出了管外换热准则关系式和空气流动阻力准则关系式,并与第一代平片型叠片的试验结果进行对比。结果表明,两种翅化比的波纹型叠片在常规换热工况下的传热性能相当,但比平片型叠片均提高了约9%;当翅化比相同时波纹型叠片的空气流动阻力比平片型叠片增大18%左右,但适当改小翅化比后,波纹型叠片在传热性能不降低的情况下,空气流动阻力可降低至仅比平片型叠片大2.5%左右。 相似文献
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矩形翅片椭圆管热交换器流动和换热特性的数值模拟 总被引:8,自引:0,他引:8
利用CFD计算方法,对矩形翅片椭圆管热交换器进行了数值模拟,得到其在不同风速下的流动和换热特性,并就椭圆管和圆管之间阻力与换热特性进行了计算比较,分析讨论了片距及管排数对阻力特性的影响,为风洞热交换器设计提供依据。 相似文献
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This paper is a continuation of the authors’ previous work on spiral coil heat exchangers. In the present study, the heat
transfer characteristics and the performance of a spirally coiled finned tube heat exchanger under wet-surface conditions
are theoretically and experimentally investigated. The test section is a spiral-coil heat exchanger which consists of a steel
shell and a spirally coiled tube unit. The spiral-coil unit consists of six layers of concentric spirally coiled finned tubes.
Each tube is fabricated by bending a 9.6 mm diameter straight copper tube into a spiral-coil of four turns. The innermost
and outermost diameters of each spiral-coil are 145.0 and 350.4 mm, respectively. Aluminium crimped spiral fins with thickness
of 0.6 mm and outer diameter of 28.4 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Air
and water are used as working fluids in shell side and tube side, respectively. The experiments are done under dehumidifying
conditions. A mathematical model based on the conservation of mass and energy is developed to simulate the flow and heat transfer
characteristics of working fluids flowing through the heat exchanger. The results obtained from the present model show reasonable
agreement with the experimental data. 相似文献
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翅片管换热器是高效节能钢带式果蔬绿色干燥装备的供热装置,通过对翅片管换热器的翅化比、对流换热系数、传热系数及阻力的计算,得到了翅片管换热器的压降及翅片管的管数,计算结果表明翅片管换热器换热能力强,传热系数高。 相似文献
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Hossein Shokouhmand Shoeib Mahjoub Mohammad Reza Salimpour 《Journal of Mechanical Science and Technology》2014,28(6):2385-2391
The present study documents the constructal design and optimization of finned tubes used in air-cooled heat exchangers. The considered tubes are equipped with annular fins. The aim is to minimize the overall thermal resistance by morphing the geometry. The geometrical and thermo-physical parameters considered are the number of fins, ratio of fin height to tube diameter, Stanton number, ratio of fin conductivity to air conductivity, ratio of in-tube fluid conductivity to air conductivity and dimensionless pressure drop. Two constraints are applied in the optimization process: fixed overall volume of heat exchanger and fixed volume fraction of fin material. It is found that there exist optimal values for the number and the height of fins. Moreover, the optimal heat transfer has an extremum in a special volume fraction of fin material. 相似文献