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本文主要阐述了板翅式换热器的翅片形状对换热效果及阻力特性的影响,并给出了二种不同形状散热翅片的试验数据及曲线。 相似文献
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对椭圆芯管矩形翅片和大功率晶闸管用热管散热器偏心圆芯管矩形翅片的传热进行了分析和数值模拟,获得了相应的肋效率曲线,并与已有的近似解作了比较。初步考查了偏心度、材料变物性和翅基温度的不均匀性对偏心圆芯管矩形翅片传热的影响。 相似文献
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本文对狭窄矩形槽道内水平矩形翅片管束的自然对流放热进行了实验研究,揭示了矩形翅片和张力绕片椭圆管束 的放热强度与板间距d、管间距S1、S2及空气流通截面 相似文献
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本文在对带有百叶窗的管带式散热器进行单元传热及流阻特性分析的基础上,提出了散热器结构参数的优化数学模型,并采用混合罚函数法,对实例进行了优化计算. 相似文献
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低雷诺数流动错位翅片传热和压降特性的实验研究 总被引:1,自引:0,他引:1
通过对油水板翅式换热器进行的性能试验,得到了低雷诺数流动下板翅式换热器翅片侧传热与阻力特性的数据,在此基础上获得了错位翅片传热因子与摩擦系数的准则关系式,传热因子和摩擦系数的最大计算误差分别为0.62%和1.44%。根据这些准则关系式提出了一个衡量翅片质量的经济系数。 相似文献
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如何在较低功耗下,使服务器基板CPU低于规定温度已成为数据中心冷却问题的关键。研究了沟槽式水冷散热器对服务器基板芯片的散热。首先,通过开展沟槽式散热器冷却一个模拟CPU服务器基板的实验,对散热器水冷却过程的流动特性和传热特性做了研究,并分别获得"压降-流量"和"进口水温-流量"的性能拟合公式。其次,开展采用集成式沟槽散热器冷却含多CPU服务器基板的实验研究,通过实验测试,改变冷却水的流量和入口温度,以期获取芯片温度为70和80℃时所提供的最小能耗。实验结果表明:进口温度为25℃时,芯片温度维持在80℃以下的最佳流量为0.8 L/min;使芯片温度稳定在70℃以下的最佳流量为1.0 L/min。 相似文献
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为了获得翅片间距Pf对平直翅片管换热器的传热与阻力特性的影响规律,根据相似模化原理对3种不同Pf的平直翅片管换热器进行了试验研究。结果表明:雷诺数Rea在4 000~8 000范围内,努赛尔数Nua数随Rea的增大而增加,欧拉数Eua随Rea的增大而降低;同一Rea下,Nua随Pf减小而增加,但增加不明显,Eua随Pf增大而降低;同一Rea下,Pf越大,综合流动传热性能越好,但实际换热面积会减小,需综合考虑。研究成果可为汽轮发电机平直翅片管换热器的结构和性能优化提供依据。 相似文献
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This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number Re from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number Nu have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions. 相似文献
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《International Journal of Heat and Mass Transfer》1987,30(2):341-349
Analytic expressions for the one-dimensional temperature distribution in a pin fin or a straight fin of rectangular profile are derived if various types of boiling occur simultaneously at adjacent locations on such a fin's surface. The heat transfer coefficients for the transition and nucleate boiling are taken as being the power functions of the wall superheat and that for film boiling as being constant. The number of cases analysed is 66. Some of the results obtained are compared with those of experiments carried out elsewhere. A quite reasonable degree of agreement is found between the theory and the experiment carried out in practice. 相似文献
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In the present study, compact water cooling of high‐density, high‐speed, very‐large‐scale integrated (VLSI) circuits with the help of microchannel heat exchangers were investigated analytically. This study also presents the result of mathematical analysis based on the modified Bessel function of laminar fluid flow and heat transfer through combined conduction and convection in a microchannel heat sink with triangular extensions. The main purpose of this paper is to find the dimensions of a heat sink that give the least thermal resistance between the fluid and the heat sink, and the results are compared with that of rectangular fins. It is seen that the triangular heat sink requires less substrate material as compared to rectangular fins, and the heat transfer rate per unit volume has been almost doubled by using triangular heat sinks. It is also found that the effectiveness of the triangular fin is higher than that of the rectangular fin. Therefore, the triangular heat sink has the ability to dissipate large amounts of heat with relatively less temperature rise for the same fin volume. Alternatively, triangular heat sinks may thus be more cost effective to use for cooling ultra‐high speed VLSI circuits than rectangular heat sinks. 相似文献
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利用有限容积法,建立了环形空间内单相流体竖直向上流动过程中流动和传热的稳态模型。模型将环形空间内管设置为具有固定生热速率的发热体;流体与内管壁之间设置流动和传热边界层,以更精确的描述壁面位置流体与固体之间动量和热量的耦合传递过程。通过与常物性模型的对比,流体密度、导热系数和黏度随温度变化的变物性模型,在传热能力上具有一定的减少,流体与固体传热面之间的界面剪切力稍有下降。通过比较常物性模型和变物性模型的Re和Ri,结果表明,随着流体强制循环速度的加大,流体物性变化对流动和传热过程的影响逐渐减小。 相似文献