管壳式换热器的优化设计

管壳式换热器的优化设计,由于我含的设计参数较多,难度较大,为此需要寻找一种简单可靠的方法。本文将换热器年净收益最大原则,导出了管壳式换热器最佳传热效率的计算式,进而求出最佳传热量、最佳传热单元数,最佳的热面积等参数。     

基于经济流速的管壳式换热器优化设计

基于换热器总费用最低的原则,在初定换热器结构形式后,提出了一种计算最佳流速,进而优化换热器设计的方法。使换热器在比较经济的条件下运动,为企业创造更大的经济效益。     

再生式换热器的优化设计

指出以换热器流通面积,冷、热流体的接触面积之比,和转子转速等5个特征值作为优化判据,将换热设备的年运行费用作为寻优目标函数。运用Daridon.f.Powell罚函数的无约束化极小方法(SUMT)求解。避免了直接求导数的复杂的数学运算。并附实例优化计算结果列于表中,得出多种参数的最佳值。和优化结果。     

U形管式换热器管板的优化设计

简要介绍了U形管式换热器管板设计规范;并通过MATLAB编程计算和绘图,实现了对U形管式换热器管板的优化设计。该研究对于U形管式换热器的工程设计具有一定的参考价值。     

基于U形管式换热器的优化设计研究

文章简要介绍了U形管式换热器及其换热管的排列形式和原则；运用MATLAB做出了直径在400mm-2000mm范围内的布管数、管板厚度以及换热面积的变化趋势图，拟合出各自的变化曲线，并得出最优值。文章的设计与研究对于U形管式换热器的工程设计具有一定的参考价值。     

基于正交试验的钎焊板式换热器优化设计

按钎焊板式换热器设计制造要求,本文选择波纹深度、波纹倾角、波距为影响钎焊板式换热器换热性能的主要因素,以传热系数为目标函数设计正交试验方案,基于Fluent仿真软件分析了各参数对换热性能的影响。由极差分析得到各结构参数对换热性能影响的主次关系,波纹深度是影响换热器换热性能的最主要因素,最后得到了一组优选参数。     

换热器网络优化设计

本文采用了Ｂ Ｌｉｎｎｈｏｆ等提出的“窄点技术”，编制了不同于问题表格法的直接求解窄点位置的程序，并且运用组合曲线法及温焓图，编制了ＦＯＲＴＲＡＮ７７计算程序对换热器网络进行优化设计。     

气动分置式斯特林制冷机冷热端狭缝换热器的优化设计

冷热端换热器的优化对于提高气动分置式斯特林制冷机的性能至关重要。本文利用SAGE软件对斯特林制冷机进行优化设计,研究了冷热端狭缝式换热器的狭缝宽度、狭缝数量和翅片厚度对制冷机性能的影响。模拟结果表明,适当减小热端换热器的狭缝宽度和数量,可以有效提高斯特林制冷机的性能,冷热端换热器都存在最优的狭缝宽度和数量,同时,冷端换热器没有热端换热器的优化潜力大。     

紧凑型板壳式换热器导流结构优化设计

对于紧凑型板壳式换热器，导流结构的优化设计是至关重要的。对常用导流筒进行流体动力学分析，发现存在严重的物流分配不均现象。介绍了一种新的导流结构，流体动力学分析显示该结构可显著提高流体进入内筒的均匀性。将流体动力学分析与优化设计技术相结合，介绍了基于ANSYS—APDL的优化过程，以流体不均匀性最小为优化目标，建立合理的优化数学模型，获得最优化结构设计。     

管壳式换热器的优化设计

本研究从最佳经济效益的角度出发，首先考虑了管壳式换热器的现状，然后依据这些现状，提出了可行性的优化设计流程，最后结合具体应用实例，分析设计与优化结果。     

Observer-based monitoring of heat exchangers

The goal of this work is to provide a method for monitoring performance degradation in counter-flow double-pipe heat exchangers. The overall heat transfer coefficient is estimated by an adaptive observer and monitored in order to infer when the heat exchanger needs preventive or corrective maintenance. A simplified mathematical model is used to synthesize the adaptive observer and a more complex model is used for simulation. The reliability of the proposed method was demonstrated via numerical simulations and laboratory experiments with a bench-scale pilot plant.     

螺旋角度不同的螺旋折流板换热器壳程传热性能研究

对螺旋角度分别为25°、30°和40°的螺旋折流板换热器壳程传热性能进行了试验与研究,同时对螺旋角度为25° 30°和40°的螺旋折流板换热器与传统的弓形折流板换热器壳程传热性能进行了比较.实验结果表明,螺旋角为40°的螺旋折流板换热器的传热效率最高,螺旋折流板换热器的壳程传热效率都比传统的弓形折流板换热器壳程传热效率高.     

An effectiveness-NTU method for triple-passage counterflow heat exchangers

A new effectiveness-NTU method is developed for a special type of heat exchangers. in which the fluid of a passage is in simultaneous thermal contact with two separate fluids flowing in the opposite direction. An extensive amount of numerical simulations are carried out by an iterative method for wide ranges of dimensionless parameters such as ratios of capacity rates, NTU’s, or a dimensionless inlet temperature. The large body of resulting data are then effectively reduced to a small number of simple equations and graphs by introducing a new effectiveness, ε. ε is defined as the ratio of actual heat transfer to the maximum heat transfer obtained when the NTU’s become very large while the ratio of two NTU’s is kept constant. The developed method is readily applicable to the cycle analysis and design, in the same way as the ε-NTU method for the usual double-passage heat exchangers.     

Experimental investigation on the airside performance of fin-and-tube heat exchangers having herringbone wave fins and proposal of a new heat transfer and pressure drop correlation

The heat transfer and friction characteristics of fin-and-tube heat exchangers having herringbone wave fins were experimentally investigated. Eighteen samples having different fin pitches (1.34 mm to 2.54 mm) and tube rows (one to four) were tested. For all the samples, the waffle depth and the corrugation angle of the fin was 1.14 mm and 11.7^o respectively. Results showed that the j factors were insensitive to fin pitch, while f factors increased as the fin pitch increased. As the number of tube rows increased, both the j and f factors decreased. However, the effect of tube row diminished as the Reynolds number increased, at least for j factors. Existing correlations failed to adequately predict the present data. A new correlation was developed based on existing data, which significantly improved the predictions of the present data.     

Preventing loose bolts and reducing the number of bolts required in plate heat exchangers

There are many methods for assembling various parts of a product. Bolts are widely used because they easily hold components tightly together and are simple to install and remove. However, bolts require other components to prevent loosening, which increases their cost. This study proposes equations that explain why bolts become loose and solves them using finite element analysis. Furthermore, because the number of bolts used in attaching components is often based on the empirical experience of designers in the field, the safety margin in plate heat exchangers is often too high. The equations presented in this study permit the number of bolts to be reduced. These equations take into consideration the relationship between the critical shear force acting on the screw and the normal force acting on the cooling plate induced by the working fluid.     

Experimental study on heat transfer characteristics of internal heat exchangers for CO2 system under cooling condition

This paper presents the heat transfer characteristics of the internal heat exchanger (IHX) for CO₂ heat pump system. The influence on the IHX length, the mass flow rate, the shape of IHX, the operating condition, and the oil concentration was investigated under a cooling condition. Four kinds of IHX with a coaxial type and a micro-channel type, a mass flow meter, a pump, and a measurement system. With increasing of the IHX length, the capacity, the effectiveness, and the pressure drop increased. For the mass flow rate, the capacity of micro-channel IHX are higher about 2 times than those of coaxial IHX. The pressure drop was larger at cold-side than at hot-side. In the transcritical CO₂ cycle, system performance is very sensitive to the IHX design. Design parameters are closely related with the capacity and the pressure drop of CO₂ heat pump system. Along the operating condition, the performance of CO₂ IHXs is different remarkably. For oil concentration 1, 3, 5%, the capacity decreases and the pressure drop increased, as compared with oil concentration 0%. This paper was recommended for publication in revised form by Associate Editor Yong Tae Kang Prof. Young-Chul Kwon received his B.S. degree in Precision Mechanical Engineering from Pusan National University, Korea, in 1989. He then received his M.S. and Ph.D. degrees from POSTECH, in 1991 and 1996, respectively. Dr. Kwon is currently a Professor at the Division of Mechanical Engineering at Sunmoon University in Chungnam, Korea. He serves as a chief of the Institute of Automation and Energy Technology. Dr. Kwon’s research interests include heat exchanger, CO₂ cycle, heat pump, and energy recovery ventilator for HVAC&R. Mr. Dae-Hoon Kim is currently Doctoral student at the Mechanical Engineering from Hanyang University in Seoul, Korea. His research topics include experimental and numerical of CO₂ heatpump system. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and Its Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner. Prof. Jae-Heon Lee received his B.S. degree in Mechanical Engineering from Seoul National University, Korea, in 1971. He then received his M.S. and Ph. D. degree from Seoul National University in 1977 and 1980, respectively. Dr. Lee is currently a Professor at the school of Mechanical Engineering at Hanyang University in Seoul, Korea. Dr. Lee is currently a president at the Korea Institute research interests include simulation of thermal fluid and Plant engineering and construction. Dr. Jun-Young Choi received his B.S. degree in Mechanical Engineering from Yonsei University, Republic of Korea, in 1989. He then received his M.S. and Ph. D. degrees from Yonsei University in 1991 and 1999, respectively. Dr. Choi is currently a chief researcher with the 18 years experience on the energy performance testing of HVAC/R product. He is now assigned to the Energy Technology Center at Basic Industry Division at Korea Testing Laboratory. He has been involved in the development of Design and Manufacturing Technology for Air-Conditioner E.E.R. and Performance Testing Equipment for Cooling and Heating System with Non-CFCs, and natural refrigerants. He has conducted a study on the Analysis of Refrigerating & Air-Conditioning Equipment Industry and Its Forecasting Supervising and Testing for Performance of Refrigerator, Freezer and Air-Conditioner. Dr. Sang Jae Lee received his Ph.D. degree in Mechanical Engineering from Hanyang University, KOREA, in 2008. Dr. Lee is currently a Researcher at the Korea Institute of Industrial Technology in Cheonan, Korea. Dr. Lee’s research interests CO₂ heatpump system, liquid desiccant air conditioning system and Micro heat exchanger.     

换热器管与管板连接的工艺对比

介绍了机械、橡胶、液压以及爆炸等胀管新工艺各自的原理和特点,着重对这几种胀接工艺的性能进行了比较,为实际生产选择合理的胀管工艺提供指导.     

换热器管板胀接槽的加工

介绍换热器的铝管与合金结构钢的管板胀接结构,并介绍加工管板孔槽的工艺装备。     

汽车车门的设计

开闭件是车身关键运动件,其灵活性、坚固性、密封性等因素对汽车产品的使用质量有严重的影响.因此,生产商对开闭件的制造均十分重视,开闭件质量的好坏,实际上也直接反映了生产商的工艺制作水平的高低.针对车门结构的确定、附件的布置、运动校核、结构的统一协调、密封性的处理以及车门的安装等方面进行了研究,结合产品开发的具体实践,对车...     

换热器CAPP系统开放式结构的研究与实现

针对换热器CAPP系统和开放式程序结构,提出基于数据库的换热器CAPP系统总体结构,建立基于数据库的CAPP系统,实现数据库表结构设计和维护的开放性,应用程序在图形绘制、数据输入、打印输出和制造工序编制等方面都具有良好的开放性。