管壳式换热器传热传质特性研究综述

换热器是各种具有热能行业中应用最为广泛的设备之一,往往占设备总投资的很大一部分。本文设计了用于LNG的管壳式换热器,并研究了不同几何结构参数的管壳式换热器壳侧和管侧对传热、压降和换热器体积的影响。通过改变换热管外径、中心筒直径和层数来分析绕管换热器壳侧和管侧的传热性能的影响因素;并得出了管壳式换热器内速度场,温度场,相变含汽率和平均沸腾传热系数的分布规律。比较管壳式换热器内流体流动和传热特性,分析了不同质量流量对LNG汽化传热性能的影响及对换热器壳侧相变传热及两相流动对设备性能的影响。对改善换热设备性能并提高换热效率的研究提供了参考。     

换热器折流板最大间距的探讨

本文以ＤＮ４００水－水换热器设计计算为例，说明ＧＢ１５１－８９《钢制管壳式换热器》中关于折流板的最大间距应不大于圆筒内直径的规定是不尽合理的，不利于壳程流体压力降的解降，并提出了相应的建议。     

管壳式换热器研究进展

指出了传统单弓形管壳式换热器存在的缺点,分别从强化传热和优化壳程压降两个方面论述了管壳式换热器的研究进展,并对各类强化传热和优化压降的机理做了介绍,最后提出了一种新型复合管壳式换热器的理念,为管壳式换热器的研究与发展提供依据。     

重力式热管的传热过程与传热计算

热管是一种新型高效传热元件。用这种元件组成的换热器结构简单,运行可靠,使用方便,检修量小。气-气式换热器比一般管壳式换热器约轻1/2～2/3;管壳式换热器1米~3体积空间仅能布置30～40米~2传热面积,而热管式换热器1米~3体积空间则能布置120～150米~2传热面积,约为管壳式换热器的4倍。由于热管     

HTRI软件在管壳式换热器工艺设计与优化中的应用

介绍化工企业常用的管壳式换热器的特点和管壳式换热器工艺设计的过程,利用HTRI软件对管壳式换热器工程实例的工艺设计与优化过程进行分析。     

纵流式管束支撑物的结构及性能对比

纵流式管束支撑物使管壳式换热器壳程流体呈纵向流动，因而该类换热器具有传热效率高、压降小，有效消除了流体诱导振动等特点。本文阐述了纵流管束支撑物的结构变化对换热器综合性能的影响，为改进和优化管壳式换热器提供参考。     

壳程流体纵向冲刷型高效气-气管壳式换热器的传热与流阻性能的研究

本文以缩放管和螺旋槽管为强化传热管,以空气为传热介质,研究了在换热器壳程中以气体纵向冲刷为结构特征的气-气管壳式换热器的传热与流阻性能,并与弓形隔板管壳式气-气换热器在相同传热温差与传热负荷,相同气体流量与气体压降的条件下做了传热性能的比较,结果表明,缩放管气-气管壳式换热器的总传热系数要比弓形隔板管壳式气-气换热器高64.8%,可节省40%的传热面积.     

换热器折流板最大间距的探讨

本文以ＤＮ４００水－水换热器设计计算为例,说明ＧＢ１５１－８９《钢制管壳式换热器》中关于折流板的最大间距应不大于圆筒内直径的规定是不尽合理的,不利于壳程流体压力降的降低,并提出了相应的建议。     

运用ASPEN B-JAC设计管壳式换热器

描述了运用ASPEN B-JAC换热器计算软件进行管壳式换热器设计的步骤,讨论了换热器管程壳程优化设计的要点以及利用ASPEN B-JAC进行换热器设计优化过程中应注意的问题,为管壳式换热器的优化设计提供了参考。     

用六水氯化钙作为相变材料的换热器储热性能研究

研究了一种以传统的管壳式换热器作为结构基础、管内充填相变材料——六水氯化钙的新型相变材料换热器的储热性能。对这种新型相变材料换热器分别通入温度不同的冷热流体，利用温度测试系统对其进口、出口的温度进行了测试。实验结果表明，这种相变材料换热器结构能将温度较高的热流体的热能通过其管内充填的相变材料储存起来，必要时又可以将储存的热能释放给所需的流体中，从而使其既具有热量交换的功能又具有热量储存的功能。它主要适用于温室、暖房、工业生产中的低品位热能的回收和利用，还可以应用于热能供应与人们需求之间不一致的场合，如太阳能热利用、采暖和空调领域等。     

管壳式换热器的优化设计

管壳式换热器是广泛应用于各个领域的工业设备,在国民经济中具有非常重要的作用,管壳式换热器的效率问题是设计工作的核心。本文利用优化设计原理,建立了以管壳式换热器优化设计模型。分析了影响年总费用的因素,编制了管壳式换热器优化设计计算机程序。最后给出了一个计算实例说明优化设计程序的使用。     

管壳式换热器的优化设计

管壳式换热器是广泛应用于各个领域的工业设备，在国民经济中具有非常重要的作用，管壳式换热器的效率问题是设计工作的核心。本文利用优化设计原理，建立了以管壳式换热器优化设计模型。分析了影响年总费用的因素．编制了管壳式换热器优化设计计算机程序。最后给出了一个计算实例说明优化设计程序的作用。     

管壳式换热器流体流动与耦合传热的数值模拟

结合化工行业中使用的某型号管壳式换热器的结构图和工艺参数,对换热器的结构进行了合理的简化,利用ANSYS参数化建模方法建立了管壳式换热器的参数化模型。在ANSYS FLUENT14.0数值模拟软件中对换热器的流体流动以及耦合传热进行了数值模拟,得到管程和壳程流体的流速分布、压降情况、温度场变化的细节信息。该工作对于设计传热效率高、流体阻力小的换热器进行了有益探索。     

Heat exchanger network synthesis with detailed exchanger designs: Part 1. A discretized differential algebraic equation model for shell and tube heat exchanger design

A new method for the detailed design of shell and tube heat exchangers is presented through the formulation of coupled differential heat equations, along with algebraic equations for design variables. Heat exchanger design components (tube passes, baffles, and shells) are used to discretize the differential equations and are solved simultaneously with the algebraic design equations. The coupled differential algebraic equation (DAE) system is suitable for numerical optimization as it replaces the nonsmooth log mean temperature difference (LMTD) term. Discrete decisions regarding the number of shells, fluid allocation, tube sizes, and number of baffles are determined by solving an LMTD-based method iteratively. The resulting heat exchanger topology is then used to discretize the detailed DAE model, which is solved as a nonlinear programming model to obtain the detailed exchanger design by minimizing an economic objective function through varying the tube length. The DAE model also provides the stream temperature profiles inside the exchanger simultaneously with the detailed design. It is observed that the DAE model results are almost equal to the LMTD-based design model for one-shell heat exchangers with constant stream properties but shows significant differences when streams properties are allowed to vary with temperature or the number of shells are increased. The accuracy of the solutions and the required computational costs show that the model is well suited for solving heat exchanger network synthesis problems combined with detailed exchanger designs, which is demonstrated in Part 2 of the paper.     

换热器设计方案多级可拓综合评价

为了更全面、系统、多层次地评价换热器等设备的设计方案,基于可拓学理论,提出了换热器设计方案多级可拓综合评价指标体系,创建了换热器设计方案多级可拓综合评价模型,提出了换热器设计方案多级可拓综合评价方法。以管壳式换热器的设计方案为例,对其进行了多级可拓综合评价,实现了设计方案的评估与优选,并验证了评价结果的客观性与有效性。该评价方法具有可靠性高、实用性强等特点。     

Numerical simulation and structure optimization of spiral wound heat exchanger with novel spacing bars

Spiral wound heat exchangers are widely used in industrial production for their advantages, such as large heat transfer areas and compact structures. However, their compact design also poses significant difficulties for numerical simulation and experimental research. The spacing bar between tube bundles has an essential impact on the performance of wound tube heat exchangers. This paper presents a new type of spacing bar vertically installed on the core barrel of the spiral wound heat exchanger to enhance the comprehensive heat transfer performance. A numerical model of a new type of wrapped tube heat exchanger has been constructed, which agrees with experimental results. Under the same working conditions, the comprehensive heat transfer performance on the shell side of the spiral wound heat exchanger with new spacing bars is increased by 7.4%–10.5% compared with the traditional structure. On this basis, the influence of the new spacing bar's structural parameters on the heat exchanger's performance was studied, and the empirical correlation between the structural parameters and operating conditions of the new spacing bar and the performance of the heat exchanger was fitted. The research results have guiding significance for the design of spiral wound heat exchangers.     

浮头式热器管板计算问题的讨论

随着工业的发展,换热器成为石油、化工、冶金、电力、轻工等业普遍应用的一种工艺设备.管壳式换热器在工业装置的换热设备中占有相当的比重.管板是管壳式换热器的主要部件,管板的设计是否合理对确保换热器的安全运行,节约材料,降低制造成本及减少加工制造困难是至关重要的.而管板的计算方法又有多种,情况也十分复杂.     

管壳式换热器管板布管数量简易计算

管壳式换热器设计工作中,管板上管孔数量是一个重要的设计数据,它是决定一台换热器的换热面积、管板的计算厚度、壳程壳体计算厚度等许多结果的一个重要参数,必须绝对准确。但计数是一项繁琐的工作。通过在布管限定园内作梯形图及简易公式推导,以简化这项繁琐的工作,提高设计工作效率,缩短设计周期。     

Rayleigh–Benard convection in vertical shell and tube heat exchangers

Large scale recirculation due to unwanted free convection currents of the fluids in a vertical countercurrent shell-and-tube heat exchanger in industry obviously was the reason of severe reductions in heat transfer performance by up to 40% against the design expectations. The apparatus was operated with the cold end on top. Applying a simple one dimensional calculation of flow and heat ransfer, with backflow of the tube side fluid in some of the tubes, shows that the reductions predicted from the model are not too far from the observed ones. In comparing experimental plant data to the predictions of the model, it became obvious, that the influence of free convection on the shell side heat transfer needs to be taken into account additionally to fully explain the experimental observations. An effective remedy, as earlier suggessted is to change flow directions in shell and tubes, i.e. to operate the heat exchanger with the hot side on top. In case of the industrial heat exchanger presented in the paper, the change of flow directions in shell and tube side has been carried out in the meantime. This change actually solved the problem, and resulted in the designed performance with efficiencies around 95%.