共查询到18条相似文献,搜索用时 109 毫秒
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针对一个工业换热器管程传热强化的要求,提出基于CFD模拟的换热管选型及其结构优化方法。选择普通圆管、扁管、螺旋扭曲扁管和内置扭带圆管4种不同形状的强化传热管为考察对象,借助流体力学模拟软件Fluent6.3,对不同传热管的内部参数分布、传热系数、压降大小和综合效果等进行了模拟和比较分析,结果表明螺旋扭曲扁管的综合传热效果最佳,其中传热系数比普通圆管提高了3倍,压降小于0.5 MPa,可满足工业换热器强化传热改进的要求。通过模拟取得了螺旋扭曲扁管适宜的结构参数范围,其中扭曲程度5~15,扁度为2~2.6,通过分析管内流场的分布,证明这种特殊结构换热管对流体湍动程度和传热效果有显著强化作用。 相似文献
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人字形波纹板式换热器性能数值模拟的研究 总被引:1,自引:0,他引:1
基于简化模型的计算结果难以准确描述换热器内完整的流体流动和换热特性.为此,本文建立与人字形波纹板片完全相同的,含分配区和传热区冷热双流道换热的计算模型,用计算流体力学软件Fluent 6.3,数值模拟4组不同名义速度下流体的流动和换热情况.分析流道内速度场和温度场发现,进口分配区对流体流动分布和换热都有显著影响,还将流体在流道内的流动情况详细描述.两侧流体的压降和进出口温差的计算值与实验值的误差小于6%,较准确地反映了换热器内整体的流动和换热特性,可直接用于研究板式换热器的性能,具有一定的工程实际意义. 相似文献
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传热计算是化工计算中的重点和难点,其公式众多,计算过程繁琐。本文利用MATLAB语言强大的运算与图形表达功能,研究换热器的操作计算和设计计算,给出了计算机辅助计算的步骤。利用FLUENT软件的流体流动和传热问题的微观模拟功能,找到换热器内部的温度分布。证明有计算机辅助简化了化工过程中传热的计算,且可直观地理解换热器的传热过程。 相似文献
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在换热器性能评估平台优化设计的研究中,为了描述套管换热器在热流体动态输入温度下的换热行为,研究其温度分布变化规律,在综合考虑了流体沿流动方向的导热扩散特性、中间墙体的金属蓄热以及流体沿径向导热对出口温度瞬态响应的影响的基础上,提出了以墙体侧蓄热量为突破点的动态相变仿真交叉迭代简化模型,得到了在热流体动态输入温度下的换热器温度响应曲线以及换热系数的分布曲线,最后设计了换热器动态仿真平台,对仿真结果进行对比分析,结果表明墙体侧温度模型预测值和实验值数据吻合较好.最大相对误差在9%范围内,其仿真模型符合换热器的换热特性,说明上述简化模型对套管换热器相变换热的研究有较好的参考作用. 相似文献
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管程扰流传热与阻力实验中的特征长度 总被引:1,自引:0,他引:1
以管程扰流雷诺数、努塞尔数和达尔西阻力因数中的特征长度为切入点,结合各特征数的物理意义提出管程扰流特征长度选取准则.指出管程扰流有动态扰流和静态扰流之分,应选取不同的特征长度.进而结合管程转子组合式强化传热与自清洁装置"洁能芯"的传热和阻力实验,将不同特征长度条件下的实验数据处理结果进行比较讨论,验证管程扰流特征长度选取准则,同时也阐述转子组合式强化传热装置"洁能芯"的强化传热与阻力特性.实验表明,当21 000≤Re≤56 000,与光滑圆管相比,"洁能芯"使得管程努塞尔数提高15%-20%,总传热系数提高约20%,达尔西阻力因数约为光管的3倍-5倍.实验中特征速度和定性温度分别为管程平均流速和平均温度.所提出的管程扰流特征长度选取准则对于内插件管程扰流强化传热技术具有普遍的参考价值. 相似文献
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螺旋缠绕管式换热器作为新型换热设备,与传统换热器相比,更为紧凑的管排列方式,增大了设备单位体积内的传热面积,且流体流动过程更易多流股化,从而提升传热综合效率;对设备的传热特性进行研究并与计算机技术相结合实现性能优化与计算方法改善,对于实际设备设计生产与使用具有重要意义;通过计算流体力学(CFD)方式,对螺旋缠绕管式换热器进行简化计算模型结构工作并开展数值模拟,研究不同管排列方式,相邻管层间距,壳程流速,换热管使用材料在设备换热性能方面的影响情况,得到设备优化结构,实现设备性能提升;选定管内径,管缠绕圈数,壳程流速以及管缠绕半径四个因素及其相对应水平参数开展正交试验,并分析单因素对于绕管式换热器综合传热性能PEC的影响情况及各因素的主次程度;运用Visual Basic语言进行计算程序开发,通过对流体物性参数,管内径,管缠绕圈数,管程数等进行输入并自动计算,实现压降,传热系数,综合性能指数等结果的可视化,提高后期设计工艺计算精度。 相似文献
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换热器的管间距直接影响其换热效果.针对其尺寸的设计一向受到重视的问题,为改善实验周期长、条件有限的现状,通过合理的简化,建立了小尺度管壳式换热器管程流动的物理模型和数学模型,利用CFD软件FLUENT,基于结构化网格的有限体积法,运用RNG k-ε模型,在入口速度为0.6m/s及通流面积不变的情况下,分别针对三种不同结构的管程流体流动进行了仿真,得到三种结构下的流场、压力场和涡量场的分布.仿真结果表明,随着管间距的增大,管程流体流动的阻力亦有随之增大的趋势,流动趋近平稳,但换热效果随之降低,为工程设计提供了实际的依据. 相似文献
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Design and fabrication of a cross flow micro heat exchanger 总被引:3,自引:0,他引:3
A cross flow micro heat exchanger was designed to maximize heat transfer from a liquid (water-glycol) to a gas (air) for a given frontal area while holding pressure drop across the heat exchanger of each fluid to values characteristic of conventional scale heat exchangers. The predicted performance for these plastic, ceramic, and aluminum micro heat exchangers are compared with each other and to current innovative car radiators. The cross flow micro heat exchanger can transfer more heat/volume or mass than existing heat exchangers within the context of the design constraints specified. This can be important in a wide range of applications (automotive, home heating, and aerospace). The heat exchanger was fabricated by aligning and then bonding together two identical plastic parts that had been molded using the LIGA process. After the heat exchanger was assembled, liquid was pumped through the heat exchanger, and minimal leakage was observed 相似文献
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HAMDI F.A.Abdelrahim 《计算机辅助绘图.设计与制造(英文版)》2007,17(1):25-29
Influence of strip self-rotating plastic spiral elements inserted in a tube on heat transfer enhancement is studied experimentally. The strip consists of 100 self-rotating spiral elements made of plastic polycarbonate inserted in the inner tube of a concentric tube heat exchanger with a view to generating swirl flow that helps to increase the heat transfer rate of the tube. Cold water flows in the annulus whereas the hot water flows in the inner tube. The obtained experimental data are compared with the data obtained from plain tube .Experimental results confirmed that the use of self-rotating plastic spiral elements leads to higher overall heat transfer coefficient than the plain tube. This technology is not only useful for heat transfer enhancement but also can be used for self cleaning deposition fouling in heat exchanger when the flow velocity is higher than 0.2 m/sec. 相似文献
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《Journal of Process Control》2014,24(4):286-298
Compact heat exchangers have a wide range of applications where standard control strategies typically rely on the knowledge of the heat transfer model and thus on the overall heat transfer coefficient. In particular for compact plate heat exchangers, the overall heat transfer coefficient strongly varies with the manufacturer's plate design and has to be identified by means of extensive measurements. This paper presents an alternative approach for the control of compact heat exchangers which can be implemented without the knowledge of the heat transfer behavior and is robust against changes in the coolant supply system. For this, a model based control strategy is presented which relies on the total thermal energy stored in the fluids of the heat exchanger as control variable instead of the outlet temperature. Furthermore, two methods are developed in order to estimate the total thermal energy, one based on a Kalman Filter and the other one on quasi-static considerations. Finally, the proposed control and estimation strategies are validated by means of simulation and measurement results on an industrial plate heat exchanger. 相似文献
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一种多效蒸发系统预估计算的软件 总被引:3,自引:2,他引:1
将多效蒸发系统计算分解为蒸发器计算和换热网络计算.换热网络计算采用线性规划求解,以免由于相平衡和传热系数计算误差,而使问题不可解。此法适用于生产指导或过程控制. 相似文献
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采用OpenGL的可视化技术和计算机编程技术,对制冷、化工领域中常用的翅片管式换热器进行可视化仿真,详细地介绍了采用三维图形来显示翅片管式换热器结构的方法,以及用颜色渐变图来显示仿真结果的方法。采用这种方法开发的翅片管换热器仿真系统具有友好的用户交互性和良好用户操作性,给翅片管式换热器的仿真和设计提供了一个友好的和形象的开发平台,可以有效地缩短换热器的设计周期,提高换热器设计质量。该文所提出的可视化仿真方法,对制冷和化工领域中应用的其他热交换设备的仿真具有应用价值。 相似文献
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提出了1种换热网络的粒子群优化设计方法,提高大规模无分流换热网络的设计速度和效果。采用超结构建立换热网络模型,以各个换热器和换热量为演化个体,以投资和运行费用最小化为优化目标,发挥粒子群的群智特点寻优计算。避免传统设计的计算复杂、不能同时优化投资和运行费用等问题,解决了换热器的换热量受换热条件约束、相互制约而影响设计的难题,保证演化过程中解的可行性,实现设计过程的智能化。以某炼油厂的常减压蒸馏过程的换热网络为实验对象,仿真研究,证明了算法有效和优越。 相似文献
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Results of heat transfer testing of heat absorption modules (HAM), heat rejection modules (HRM), and a recirculating-liquid
cooling system are reported. Low-profile, Cu-based, microchannel heat exchangers (MHEs) were fabricated and used as the HAM
as well as components for assembly of a microchannel HRM. Detailed experimental assessment of two different liquid-passing
HRMs and a microchannel-based recirculating-liquid cooling system was carried out, and benchmarked against all-solid devices
of the same geometric dimensions. Incorporating microchannel liquid flow through each fin, the device-level heat transfer
performance of the microchannel HRM was improved by up to ~50%. Detailed testing of a microchannel-based recirculating-liquid
cooling system indicate that low-profile Cu MHEs are highly effective in heat flux removal while having a small area/volume
footprint, and that enhancing the HRM performance is critical to boosting the overall performance of such recirculating-liquid
cooling systems. 相似文献
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Tadayoshi Matsumori Tsuguo Kondoh Atsushi Kawamoto Tsuyoshi Nomura 《Structural and Multidisciplinary Optimization》2013,47(4):571-581
This paper deals with density-based topology optimization considering fluid and thermal interactions, in which the Navier–Stokes and heat transport equations are coupled. We particularly focus on designing heat exchangers. In the engineering context, heat exchangers are designed while considering a certain amount of input power. Therefore it is important to maximize the performance of a heat exchanger under a constant input power. In this paper we propose a way to control the input power by introducing an extra integral equation. To be more precise, in the fluid analysis, the inlet pressure is determined by solving the extra integral equation together with the Navier–Stokes equation. By doing this we can keep the inlet power constant even when the flow channels are changed in the optimization process. Consequently, the system of equations of the fluid field takes an integrodifferential form. On the other hand, in the heat transport analysis, a single governing equation is defined for simultaneously modeling both the solid and fluid parts. The design variable is a fluid fraction whose distribution represents the topology of the solid and fluid domains. When designing heat exchangers, two different heat conditions are considered in the formulation of the optimization problems, namely temperature-dependent and temperature-independent heat sources. Through the numerical examples for designing flow channels in a heat exchanger, it is shown that distinct topologies can be obtained according to the input power and the heat source conditions. 相似文献