New Optimization Method, the Algorithms of Changes, for Heat Exchanger Design

Heat exchangers are widely used in the process engineering such as the chemical industries, the petroleum industries, and the HVAC applications etc. An optimally designed heat exchanger cannot only help the optimization of the equipment size but also the reduction of the power consumption. In this paper, a new optimization approach called algorithms of changes (AOC) is proposed for design and optimization of the shell-tube heat exchanger. This new optimization technique is developed based on the concept of the book of changes (I Ching) which is one of the oldest Chinese classic texts. In AOC, the hexagram operations in I Ching are generalized to binary string case and an iterative process, which imitates the I Ching inference, is defined. Before applying the AOC to the heat exchanger design problem, the new optimization method is examined by the benchmark optimization problems such as the global optimization test functions and the travelling salesman problem (TSP). Based on the TSP results, the AOC is shown to be superior to the genetic algorithms (GA). The AOC is then used in the optimal design of heat exchanger. The shell inside diameter, tube outside diameter, and baffles spacing are treated as the design (or optimized) variables. The cost of the heat exchanger is arranged as the objective function. For the heat exchanger design problem, the results show that the AOC is comparable to the GA method. Both methods can find the optimal solution in a short period of time.

Heat Treat ment of Die and Mould Oriented Concurrent Design

Many disadvantages exist in the traditional die design method which belongs to serial pattern. It is well known that heat treatment is highly important to the dies. A new idea of concurrent design for heat treatment process of die and mould was developed in order to overcome the existent shortcomings of heat treatment process. Heat treatment CAD/CAE was integrated with concurrent circumstance and the relevant model was built. These investigations can remarkably improve efficiency, reduce cost and ensure quality of R and D for products.

A Comprehensive Review on Heat Transfer Design Parameters in MEMS through Experimentations and Numerical Modeling

Micro electro mechanical systems are studied in this paper along to comparing the design, fabrication, and operation of such devices especially in the electronic industry. The advancements of such systems are important as scale reduction is becoming more economical and also in heat dissipation efficiencies. Furthermore, the fabrication techniques are becoming more of a challenge in today’s industrial market. In this paper we will introduce a comparative study of experimental research in the micro scale heat exchanger with varieties of industrial application primarily cooling integrated circuits. Significant effect in the process of cooling electronic devices has showed experimentally that scale variations impact into this improvement. Numerical studies have been a leading technique in the development of thermal systems especially at the micro or small scales which helps the industry to cut cost and provide innovative products at high efficiencies. There are so many approaches to numerical analysis and research, where the availability of ready to use software and data acquisition modules is variant. Material selection is also a variable in the efficiency and operations of these micro channel thermal system and heat exchangers.

Thermal Design and Optimization of Heat Pipe Radiator for Satellites

Satellite＇s thermal control subsystem （TCS） has to maintain components and structure within their specified temperature limits during satellite service life. TCS designers have to face the challenge of reducing both the weight of the system and required heater power while keeping components temperature within their design range. For a space based heat pipe radiator system, several researchers have published different approaches to reach such goal. This paper presents a thermal design and optimization of a heat pipe radiator applied to a practical engineering design application. For this study, a prospective communication satellite payload panel with applied passive thermal control techniques was considered. The thermal passive techniques used in this design mainly include multilayer insulation （MLI） blankets, optical solar reflectors （OSR）, selected thermal coatings, interface fillers and constant conductance heat pipes. The heat pipe network is comprised of some heat pipes embedded in the panel and some mounted on inner surface of the panel. Embedded heat pipes are placed under high heat dissipation equipments and their size is fixed; minimum weight of the radiator is achieved by a minimum weight of the mounted heat pipes. Hence, size of the mounted heat pipes is optimized. A thermal model was built and parameterized for transient thermal analysis and optimization. Temperature requirements of components in both worst case conditions （Hot case and cold case） were satisfied under optimal sizing of mounted heat pipes.

Design and Construction of a Spiral Heat Exchanger

In this article, the performance and applications of a Spiral Plate Heat Exchanger are demonstrated. Also, governing equation of heat transfer phenomena in such heat exchangers is discussed. Regarding the governing equations, a LAB-sized model of this type of heat exchanger was designed and constructed. Galvanized Iron sheets were used as the heat transfer surfaces. Two Galvanized Iron sheets were rolled together around a central core and, as a result, two separated channels were made. Also, a predesign simulation of the heat exchanger was done using the Fluent software to predict the performance of the heat exchanger. First the geometry was made using Gambit software environment then the model was analyzed through Fluent. Because of less fouling, easier cleaning and high heat transfer coefficient, Spiral Heat Exchanger is a good alternative to the other types of heat exchangers, especially when it’s going to handle high fouling flows or highly viscous fluids. Low fouling rate of the heat exchanger, reduces the need of cleaning and therefore the out of service will be decreased. In the constructed heat exchanger, Nusselt number increases as the mass flow rate increases. Average Nusselt number is about 100 that is very good.

Optimizing Heat Sink Performance by Replacing Fins from Solid to Porous inside Various Enclosures Filled with a Hybrid Nanofluid

The current study generally aims to improve heat transfer in heat sinks by presenting a numerical analysis of natural convection of an enclosure with hot right and cool left walls,and thermally insulated top and bottom walls.The cold wall included configurations(half circle/half square)in various sizes(S=0.1,0.2,and 0.3),numbers(N=1,2,3,and 4),and locations(C=0.35,and 0.65).A heat sink is constructed of Aluminum attached to the hot wall,and composed of five fins with protrusions.Fins of the heat sink will be examined in a solid and porous structure.The enclosure is filled with a hybrid nanofluid of Nanoparticles(MWCNT and Fe3O4)and water.The current study utilized COMSOL Multiphysics software due to its efficacy in addressing scientific and technical challenges involving partial differential equations.The solving of the governing equations is achieved using the finite element method with various parameters:Rayleigh number(Ra=10^(3)–10^(6)),Darcy number(Da=10^(-2),10^(-3)),solid volume fraction(ϕ=0–0.06)to determine stream function,isotherms lines,and average Nusselt number(Nu).The results of numerical simulations show that heat sink with solid fins have a 97%higher stream function when Ra is raised from 10^(3) to 105.Whilst with porous fin heat sink,a stream function 96%for Da=10^(-3) and 94%for Da=10^(-2).Changing solid fins to porous increases stream functions by 9%at Da=10^(-3) and 20%at Da=10^(-2).It has been found that Ra increases Nu by 44%for solid fins and 50%for porous fins.Making solid fins porous increases Nu by 54%at Ra=10^(6).The high increase in the percentage of(Nu)indicates the importance of the improvement in heat transfer,and this distinguishes the results of the current study from previous studies.Nu values were found highest for(half square)compared to(half circle),with 2%increases for numbers,11.6%for sizes,and 11%for location.Solid volume fractions for all Ra at a solid-finned heat sink increased Nu by 23%.

液滴撞击加热壁面的实验平台设计与教学应用

液滴撞击加热表面现象广泛应用于多个领域,涉及工程热力学、传热学和流体力学等多学科交叉知识。该研究构建了液滴撞击加热表面实验平台,分析了不同撞击高度和表面温度下的液滴模式及动力学特征参数。此外,基于八个方面的考虑制定并设计了实验课程,旨在提高学生的参与度和解决问题能力。对学生的满意度调查表明,学生在五个方面的满意度超过90%。

Designing the cooling system of a hybrid electric vehicle with multi-heat source

In order to reduce the power consumption and meet the cooling demand of every heat source component, three kinds of multi-heat source cooling system schemes were designed base on the characteristic of power split hybrid electric vehicle （HEV）. Using the numerical simulation meth- od, the power system heat transfer model was built. By comparing the performance of three differ- ent schemes through the Simulink simulation, the best cooling system scheme was found. Base on characteristics of these cooling system structures, the reasonableness of the simulation results were analyzed and verified. The results showed that the cooling system designation based on the numerical simulation could describe the cooling system performance accurately. This method could simplify the design process, improve design efficiency and provide a new way for designing a multi-heat source vehicle cooling system.

微通道内纳米流体传热流动特性

为提高微通道散热器的传热效率,需要对微通道进行结构优化设计。以热阻Rt和泵功Pp为目标函数,在Re=100的条件下,采用多目标遗传算法对文丘里管微通道的结构参数,如通道深度、收缩角度、喉颈宽度和扩散角度进行优化,通过遗传迭代计算得到Pareto优化解集,利用k-means聚类法对优化解集进行比较分析,通过强化传热因子η对各聚类点综合性能进行评价,得到最优的微通道结构。采用数值模拟方法,研究优化后的微通道结构的流动与传热特性。结果表明:当去离子水中加入纳米颗粒后微通道内的压降具有小幅度上升,但其流动阻力在相同Reynolds数的条件下并没有发生较大的变化。在文丘里管微通道喉部位置会产生喉部效应,强化纳米颗粒与微通道中流动工质的融合。熵产分析表明,传热熵随着Reynolds数的增大而减小,摩擦熵随着Reynolds数的增大而增大,不过总熵值中主要是传热熵占据主导地位。纳米流体随着体积分数的增加不可逆损失均小于去离子水。

采用智能进化算法的管壳式换热器详细设计

管壳式换热器是石油、化工等过程工业中应用最广泛的热量回收设备,其数学模型通常是十分复杂的非线性优化问题,现有的商业求解器和优化算法存在运算时间长、收敛困难、易陷入局部最优等难题。针对这些难题,参考管壳式换热器制造标准,将换热器内构件尺寸定义成离散变量,分别以最小化换热面积、年度总费用、环境影响因子及最大化传热效率为目标函数,建立管壳式换热器详细设计的混合整数非线性规划模型。同时,对传统智能进化算法包括遗传算法、粒子群算法及模拟退火算法进行改进,使得换热器设计变量能够在一系列离散值中自由选择,不需要对优化结果进行人工圆整处理。案例测试结果表明,改进的智能进化算法能在1.0 s内得到最优设计方案,相对于全局求解器,优化时间节约99%以上,提高了优化求解效率;相对于局部求解器,改进的智能进化算法能够获取全局最优解,换热面积节约15.4%~56.6%,年度总费用节约15.8%~77.8%,保证设计质量。通过多目标优化在不同目标函数之间进行权衡,通过灵敏度分析展示了不同设计变量对目标函数的影响趋势。

基于电发热技术的艾灸功能针织服装设计研究

以缓解白领人群因久坐导致的肩颈疼痛、腰部疲劳为出发点,基于中医穴位艾灸疗法,分析中医艾灸对缓解人体疲劳的作用及应用原理,设计开发集理疗、时尚为一体的智能电发热服装,包括一款缓解腰部疼痛的针织连衣裙和缓解肩颈疼痛的针织上衣。详细阐述设计思路及功能原理、艾灸功能模块设计、服装结构设计,并对成衣的加热功能性及穿着舒适性进行测试评价。结果表明,设计制作的服装理疗效果显著,可有效缓解人体肩颈部及腰部疲劳疼痛,且兼具功能性与时尚性。

单相液冷微通道散热器结构研究进展

微通道冷却是解决高热流密度散热问题最有效的技术之一,具有传热效率高、热阻低、结构紧凑等优点,但同时存在压降增加的问题。微通道的结构是影响其流动与传热性能的重要因素。针对该问题,简述了国内外对单相液冷微通道散热器在结构设计方面的研究进展,分为通道几何结构、扰流结构、针肋结构、多层结构、仿生结构和复合强化结构。结合各结构强化传热的原理,分析其在传热系数、压降、综合性能、均温性等方面的优缺点,并对微通道散热器常用的基体材料与加工方法进行了成本分析。基于上述总结与介绍,从应用角度展望了微通道散热器的前景与发展方向,指出复合结构的应用、仿真与实验的结合、材料学与加工技术的进步以及学科交叉是今后结构研究的重点。

建筑设计中暖通节能设计分析

建筑暖通空调系统作为建筑中不可缺少的重要组成部分,其节能设计对整个建筑的节能减排起着决定性的作用。以某酒店项目为例,根据建筑特点,对该寒冷地区酒店的暖通设计要点进行总结,依次分析了冷热源、末端设备的选择、系统管路、通风设计、防冻设计等,并总结建筑暖通设计中需要注意的节能措施,为类似建筑工程暖通空调系统设计提供参考。

火灾下部分包覆钢-混凝土组合构件升温数值模拟分析

为研究部分包覆钢-混凝土组合(steel-concrete partially encased composite,PEC)构件火灾下的传热性能,首先采用PEC构件标准火灾试验验证了二维有限元模型,然后对火灾下带有防火保护的PEC构件的升温过程及主要影响参数进行研究分析。研究表明,不同防火保护条件下,PEC构件H型钢腹板最高点温度均位于翼缘与腹板交点处,PEC构件截面温度最高点位置均位于翼缘端部。H型钢截面形状系数、翼缘厚度、腹板厚度以及H型钢高度、宽度等参数对PEC构件升温均有影响,其中影响较大的是翼缘厚度与H型钢宽度。通过将H型钢标准规格截面进行分组模拟,计算PEC构件在标准升温条件下所需防火层厚度,给出不同防火保护措施及不同耐火极限下,PEC构件防火层建议厚度设计值。

Study of High Power ICRF Antenna Design in LHD

In large helical device （LHD）, antenna loadings are different for minority ion cyclotron heating （MICH with 38.47 MHz） and mode-converted ion Bernstein wave heating （MC-IBW with 28.4 MHz）, and it is necessary to improve antenna loading with low heating efficiency to avoid arching on transmission line. To design a new ion cyclotron range of frequencies （ICRF） antenna in LHD, calculation for a simple antenna model is conducted using three-dimensional electrical magnetic code （high frequency structure simulator, HFSS） for an water loading as an imaginary plasma with low heating efficiency. At resonant frequencies, antenna loading is sensitive to strap width, and resonant frequencies are strongly related to strap height. There is no differences of RF current profile on the strap surface between resonant frequency and non-resonant frequency. The strap should be perpendicularly placed against the magnetic field line, since Faraday-shield angle will lead to a decrease in the effective antenna height.

Optimization of Selecting Air Conditioning Cold/Heat Sources with Grey Relation Analysis

Selection of air conditioning（AC） cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems. Grey relation analysis （GRA） is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information. It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management. Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible. Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sou rces.

Interpreting the dynamic effect of internal heat integration on reactive distillation columns

In this work,the impact of internal heat integration upon process dynamics and controllability by superposing reactive section onto stripping section,relocating feed locations,and redistributing catalyst within the reactive section is explored based on a hypothetical ideal reactive distillation system containing an exothermic reaction:A + BC + D.Steady state operation analysis and closed-loop controllability evaluation are carried out by comparing the process designs with and without the consideration of internal heat integration.For superposing reactive section onto stripping section,favorable effect is aroused due to its low sensitivities to the changes in operating condition.For ascending the lower feed stage,somewhat detrimental effect occurs because of the accompanied adverse internal heat integration and strong sensitivity to the changes in operating condition.For descending the upper feed stage,serious detrimental effect happens because of the introduced adverse internal heat integration and strong sensitivity to the changes in operating condition.For redistributing catalyst in the reactive section,fairly small negative influence is aroused by the sensitivity to the changes in operating condition.When reinforcing internal heat integration with a combinatorial use of these three strategies,the decent of the upper feed stage should be avoided in process development.Although the conclusions are derived based on the hypothetical ideal reactive distillation column studied,they are considered to be of general significance to the design and operation of other reactive distillation columns.

太阳电池阵基板在热真空试验中微弱热变形测量试验研究

该文主要内容研究的是在真空冷黑环境下,通过空间外热流模拟的方式结合数字化摄影测量的手段对太阳电池阵基板的微弱变形量进行测试试验研究。试验方案中采用非接触式红外灯阵模拟空间外热流的方式,同时使用空间环境模拟设备建立试验所需的真空冷黑环境,对太阳电池阵基板进行热流的施加,试验过程中采用数字化摄影测量对不同外热流作用下造成的太阳电池阵基板的微弱热变形进行测量。试验结果表明,在红外灯阵辐射热流的作用下,太阳电池阵基板2 m×1.44 m范围内的热变形测量精度优于0.05 mm,该指标可以满足测量精度要求,光学摄影测量方法可作为测量太阳电池阵基板在热真空试验过程中微弱变形的测量方法,并且试验验证该方法有效,解决热真空试验过程中太阳电池阵基板热变形测量的问题,为后续电池阵表面设计盖片及盖片之间银连片设计提供试验数据支撑。

Study on the Wireless Heat Meters

The design of a new type heat meters based on RFID technology are presented in this paper. By use of RFID technology in heat meters, the data can be exchanged between heat meters and heat supplying department by RF cards. The information can be transmitted in a non-contact way. In this way, the purpose of automatic identification can be achieved. The experimental study of the heat meters is also performed in the paper. The results show that the new type of heat meters can meet the demands of users. Compared with the ordinary heat meters, the new type of heat meters have the advantages of small in meter volume, high accuracy, no impact of water quality and good reliability.

新能源汽车电池用散热装置创新设计

本文设计了新能源汽车电池用散热装置,包括安装板,安装板上开设有若干散热孔,对应各所述散热孔设置有散热扇安装座,散热扇对应于散热孔安装在散热安装座上;散热安装座包含两组对称设置在散热孔两侧的插拔基座,两组插板基座之间形成插拔槽,散热扇的两个对立侧壁分别沿平行于安装板板面的方向活动插拔设置在两个所述插拔基座上,插拔基座上包含有快拆结构,快拆结构限位散热扇在插拔滑动方向上的位移,便于散热装置的拆卸,提高了维修的效率。