Efficiency and Effectiveness Concepts Applied in Shell and Tube Heat Exchanger Using Ethylene Glycol-Water Based Fluid in the Shell with Nanoparticles of Copper Oxide (CuO)

This article consists of an analytical solution for obtaining the outlet temperatures of the hot and cold fluids in a shell and tube heat exchanger. The system analyzed through the concepts of efficiency, effectiveness (ε-NTU), and irreversibility consisted of a shell and tube heat exchanger, with cold nanofluid flowing in the shell and hot water flowing in the tube. The nanofluid consists of 50% of ethylene glycol and water as the base fluid and copper oxide (CuO) nanoparticles in suspension. The volume fractions of the nanoparticles range from 0.1 to 0.5. The flow rate in the nanofluid ranges from 0.0331 to 0.0568 Kg/s, while two mass flow rates, from 0.0568 and 0.5 Kg/s, for the hot fluid, are used as parameters for analysis. Results for the efficiency, effectiveness, irreversibility, heat transfer rate, and outlet temperatures for cold and hot fluids were obtained graphically. The flow laminarization effect was observed through the results obtained and had significant relevance in the results.

Heat transfer enhancement of finned shell and tube heat exchanger using Fe_(2)O_(3)/water nanofluid

Heat transfer mechanisms and their thermal performances need to be comprehensively studied in order to optimize efficiency and minimize energy losses.Different nanoparticles in the base fluid are investigated to upgrade the thermal performance of heat exchangers.In this numerical study,a finned shell and tube heat exchanger has been designed and different volume concentrations of nanofluid were tested to determine the effect of utilizing nanofluid on heat transfer.Fe_(2)O_(3)/water nanofluids with volume concentration of 1%,1.5% and 2% were utilized as heat transfer fluid in the heat exchanger and the obtained results were compared with pure water.ANSYS Fluent software as a CFD method was employed in order to simulate the mentioned problem.Numerical simulation results indicated the successful utilization of nanofluid in the heat exchanger.Also,increasing the ratio of Fe_(2)O_(3) nanoparticles caused more increment in thermal energy without important pressure drop.Moreover,it was revealed that the highest heat transfer rate enhancement of 19.1% can be obtained by using nanofluid Fe_(2)O_(3)/water with volume fraction of 2%.

Theoretical Analysis of a Shell and Tubes Condenser with R134a Working Refrigerant and Water-Based Oxide of Aluminum Nanofluid (Al₂O₃)

The article analyzes a shell and tube type condenser’s thermal performance using concepts of efficiency and effectiveness. Freon 134a is used as a coolant flowing through the shell. Water or water-based aluminum oxide nanoparticles are at relatively low saturation pressure in the tube. The condenser consists of 36 tubes divided into three central regions for analysis: superheated steam, saturated steam, and subcooled liquid. The three regions contain four tubes with three steps each, that is, 12 tubes. Region I, superheated steam, includes three horizontal baffles. Profiles of temperature, efficiency, and effectiveness are presented graphically for the three regions, with fixed refrigerant flow equal to 0.20 kg/s and fluid flow rate in the tube ranging from 0.05 kg/s to 0.40 kg/s. The experimental result for vapor pressure equal to 1.2 MPa and water flow equal to 0.41 kg/s was used as one of the references for the model’s physical compatibility.

Efficiency and Effectiveness Thermal Analysis of the Shell and Helical Coil Tube Heat Exchanger Used in an Aqueous Solution of Ammonium Nitrate Solubility (<i>ANSOL</i>) with 20% H₂O and 80% <i>AN</i>

The case study is about obtaining the flow rate and saturation temperature of steam that makes it possible to heat a solution of water and ammonia nitrate (ANSOL) in a shell and helical coil tube heat exchanger, within a time interval, without that the crystallization of the ANSOL solution occurs. The desired production per batch of the solution is 5750 kg in 80 minutes. The analysis uses the concepts of efficiency and effectiveness to determine the heat transfer rate and temperature profiles that satisfy the imposed condition within a certain degree of safety and with the lowest possible cost in steam generation. Intermediate quantities necessary to reach the objective are the Reynolds number, Nusselt number, and global heat transfer coefficient for the shell and helical coil tube heat exchanger. Initially, the water is heated for a specified period and, subsequently, the ammonium nitrate is added to a given flow in a fixed mass flow rate.

Performance Assessment of a Shell Tube Evaporator for a Model Organic Rankine Cycle for Use in Geothermal Power Plant

The global energy demand increases with development and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining and harmful combustion byproducts are causing global warming. The Organic Rankine Cycle power plant is a very effective option for utilization of low grade heat sources for power generation. In the Organic Rankine Cycle heat exchangers such as evaporators and condensers are key components that determine its performance. Researches indicated that shell tube heat exchangers are effectively utilized in this cycle. The design of the heat exchanger involves establishing the right flow pattern of the interacting fluids. The performance of these exchangers can be optimized by inserting baffles in the shell to direct the flow of fluid across the tubes on shell side. In this work heat exchangers have been developed to improve heat recovery from geothermal brine for additional power generation. The design involved sizing of heat exchanger (evaporator) using the LMTD method based on an expected heat transfer rate. The heat exchanger of the model power plant was tested in which hot water simulated brine. The results indicated that the heat exchanger is thermally suitable for the evaporator of the model power plant.

Effects of R134a Saturation Temperature on a Shell and Tube Condenser with the Nanofluid Flow in the Tube Using the Thermal Efficiency and Effectiveness Concepts

The work’s objective is to analyze the influence of the saturation temperature of the R134a refrigerant on the thermal performance of a shell and tube type condenser, with water and aluminum oxide (Al2O3) nanoparticles flowing into the tube. For analysis, the heat exchanger is subdivided into three regions: subcooled liquid, saturated steam, and superheated steam. The shell and tube heat exchanger assumed as the basis for the study has 36 tubes, with rows of 4 tubes in line and three passes into the tube in each region. The parameters used to analyze the performance are efficiency and effectiveness, through variations of quantities such as saturation temperature, the nanofluid’s mass flow rate, fraction in the nanoparticles’ volume, and the number of passes in the tube in each region of the heat exchanger. The obtained results demonstrate that the efficiency is relatively high in all the analyzed situations. In each saturation temperature, the effectiveness can be increased by introducing fractions of nanoparticles in the water or increasing the number of passes in the tube.

A SURVEY OF WORKS ON THE THEORY OF TOROIDAL SHELLS AND CURVED TUBES

This paper gives a survey of works on the theory of toroidal shells which were done by our two universities in recent years.

Design of Portable Shell and Tube Heat Exchanger for a Solar Powered Water Distiller

This study presents theoretical considerations and results of a portable shell and tube heat exchanger in a solar water distiller system. The device is composed of a glass heat exchanger, which served as a condenser for vapor condensing which were produced in black paint solar absorber. It was also composed of a tank for water source and a tank for produced distilled water. Shell and tube was designed and simulated using an implicit numerical scheme. Simulation results showed that accumulated mass water greatly depended on the inlet vapor temperature and volume, heat exchanger material, coolant water temperature and volume. Thus, changing the material from stainless steel to glass in the same condition （vapor temperature, vapor volume, coolant temperature and coolant volume）. These inexpensive shell and tube heat exchangers permitted to produce 40 litre/day, distilled water from vapor with 378 K inlet temperature in atmosphere pressure. If inlet pressure increases, vapor temperature will decline and thereupon, heat exchanger＇s efficiency tangibility will increase.

Industrial Elaboration by Extrusion of PVC Tubes Loaded with Micronized Dura Palm Kernel Shell Powder

We present in this work how to use the dura palm kernel shell powders as loads for the elaboration by extrusion of PVC tubes. The transformation of dura palm kernel shells into micronized shell powder as well as its characterization was the subject of recent work. We carried out, the formulations by using the industrial scales of precision, the mixtures of the instrants with an industrial machine of mark HENSHLLE N˚2 MAIN 570762, the routine tests by ATG/DSC then by IRTF, the extrusion of the tubes with an extruder twin-screw with 9 rooms of transformation finally the tests of conformity by the observations and the analyses. We obtained for the formulations the dosage of 0%, 4.01%, 12.54%, 23.03%, 32.01%, 38.01%, 51.02% representing the percentage of hull powder in the mixture, the machine mixing gave perfectly homogeneous powders, the routine tests showed that the hull powder keeps all its properties until the end of the shaping whatever the percentage of hulls contained in the PVC, the extrusion gave tubes for each formulation and the conformity tests gave perfectly round tubes of diameter 90 × 82 mm, a coloration going from white grey at 0% to dark black at 51.02% showing the influence of the carbon black and the color of the shell powder according to its proportion. The infrared of the tubes obtained shows for each formulation a variation of the CH2 and CH bonds and a decrease of the −OH bonds. The thermogravimetric analyses and the differential calorimetric analyses of the tubes of each formulation, show each time that the quantity of shell powders in the mixture influences the PVC tubes obtained. Thus, we obtain a variation of the phase temperatures according to the dosage, giving from 108.72˚C to 76.56˚C for the glass transition temperature and from 494.71˚C to 414.56˚C for the melting temperature, at the DSC and a progressive decrease of the mass following the heat absorption with each time 4 phases instead of 5 for the unloaded PVC tubes at the ATG according to the dosage.

Mathematical Modelling of Operating Temperature Variations of Shell-and-Tube Heat Exchanger (10-E-01)

The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.

基于Aspen EDR的管壳式换热器工艺选型设计教学实践

管壳式换热器工艺选型设计是化工过程中设备设计的重要环节之一。为了避免手工计算中繁琐的计算和复杂的校核问题,以无相变的乙醇冷却器为例,探讨Aspen EDR软件在管壳式换热器工艺选型设计中的实践应用。通过Aspen EDR软件的教学示范,激发学生学习积极性和主动性,提升学生运用理论知识分析和解决复杂化学工程问题的能力,强化专业软件应用能力。

不同螺旋缠绕异形管换热器壳程性能数值研究

缠绕管的形状对螺旋缠绕管换热器的传热能力有重要影响,本文建立了具有不同截面形状的螺旋缠绕管换热器模型,数值研究了八种不同截面形状的缠绕管对螺旋缠绕管换热器壳程流动与传热性能的影响。相比于传统圆管,三叶管和水滴管对壳程流体造成的扰动较大,增强了螺旋缠绕管换热器的综合换热性能,而三叶管则具有最大换热能力。进一步分析了不同冲刷方式对螺旋三叶管换热器和螺旋水滴管换热器壳程性能的影响,结果表明:在相同的进口工况下,螺旋三叶管换热器壳程努塞尔数相比于传统圆管提高了11.8%~15.5%,阻力系数增大了41.9%~49.6%;螺旋水滴管换热器壳程努塞尔数相比于传统圆管提高了2.8%~4.3%,阻力系数增大了3.2%~6.8%;在雷诺数为2 603~5 206的工况条件下,管截面与流动方向夹角为0°的三叶管换热器综合换热性能最好,而管截面与流动方向呈逆流形式的水滴管换热器综合换热性能优于顺流形式。

沉管安装测量塔倾斜位姿修正方法

在沉管管节沉放对接施工过程中,针对管节本体发生形变导致测量塔与管节相对几何位置发生微变,从而影响沉管安装定位精度的问题,本文在管节本体与测量塔结构上分别加装倾斜仪监测设备,与管节内安装的倾斜仪在同一坐标体系下进行标定,在沉管沉放对接过程中实时监测与修正测量塔定位倾斜误差。经贯通测量比对验证发现,该方法可以有效降低管节形变对沉管安装定位精度的影响,取得了良好的应用效果,为沉放对接施工决策提供了参考。

海洋平台换热器橇海水系统超级双相钢耐蚀分析

集合国外行业标准和国内使用经验,对海洋石油平台管壳式换热器橇内海水系统超级双相钢管线频繁泄漏进行研究,探析冶金状态、海水温度、焊接特性、材料污染为超级双相钢在海水系统中腐蚀泄漏的主要原因。从系统工艺、冶金、焊接、运行等方面分别提出减少泄漏风险的方法,并在后续设备改造中得到良好的应用。

管壳式换热器弓形折流板的结构优化

为研究某高温烟气急冷器空气二次冷却系统的流动与传热特性,建立了管壳式换热器简化模型,运用ANSYS软件进行数值模拟,分析了折流板数量、相对缺口高度、折流板间距和换热器进出口管布置方式对换热器性能的影响。结果表明:折流板数量越多,相对缺口高度越小,换热器压降越大,换热系数越大,综合性能指标越小;高温区域折流板间距小、低温区域折流板间距大的换热器比等间距折流板换热器平均换热系数提高了4.3%,平均综合性能指标提高了2.3%;空气出口管布置在热流体进口侧比布置在热流体出口侧平均换热系数提高了6.5%,平均综合性能指标提高了4.3%。

管壳式换热器换热管强化传热研究

研究了油库夏季高温导致的油气回收工艺中吸附罐回收率低、吸收塔解吸效率低、油气回收系统能耗过高以及安全隐患较多等问题。将温度较低的地下水作为冷却水,从实践的角度构建多种强化传热结构的管壳式换热器并采用CFD的方法对其热力学与水力学性能进行多方面探究。结果表明当油气在管壳式换热器壳程中流动时,热流可以获得更好的冷却效果;油气在壳程流动时,CIRF型换热管具有最佳的热力学性能,RAW型换热管具有最佳的水力学性能。综合油气回收工况与计算结果配置CIRF型换热管的管壳式换热器在油气回收工艺中有着较强的适用性,其可以在有效提高油气的冷却效果的同时兼顾换热器的水力学性能。

弓形折流板换热器流动与传热性能的数值模拟

为了探究折流板结构对换热器整体性能的影响,课题组通过FLUENT模拟分析弓形折流板板间距以及缺口高度占比这2个关键变量,得到不同条件下换热器流场和温度场的分布情况,并以换热系数h、压降ΔP以及综合性能参数η作为换热评价指标,研究了不同结构参数对换热性能的影响,并分析了2个关键变量之间的关联性。结果表明:随着板间距的减小,流动与传热“死区”区域变小,换热系数及壳程压降增大,板间距较小的换热器在低入口速度工况下综合性能相对较好;当板间距为185 mm时,换热系数和压降随板缺口高度占比的增大而减小,此时选择缺口高度占比为0.30可获得较佳综合性能;另外,通过研究2个变量间的关系发现板间距较小时应选择相对较大的缺口高度占比以保证其较优性能。

双管程管壳式换热器的流动与传热机理分析

为探究双管程换热器内部流体的流动与传热机理,建立单管程、双管程换热器的数值计算模型,分析单管程、双管程换热器性能的异同,并探究了不同折流板配置下的双管程换热器内部流体的湍流流动和传热特性。研究结果发现,双管程换热器的管程压降远大于单管程换热器,其管程流体在由第一管程进入第二管程时,会有较大的逆压梯度,在管程封盖中部分流体从主流流体中分离,形成涡流和流动死区,三种不同折流板配置的双管程换热器中,螺旋流换热器的壳程流体混合地较为均匀,并取得了优良的壳程综合性能。研究内容可为双管程换热器的性能优化提供指导,也为热力系统中换热器的选型和结构优化设计提供了理论参考。

Shell型旋风管内气相流场的数值模拟

应用Fluent软件中的雷诺应力输运模型(RSM)对shell型旋风管内的三维强旋湍流气相流场进行了数值计算。计算值与实验值对比结果表明,二者吻合较好,验证了数值模拟的可靠性。通过数值计算,分析了排气管附近的短路流以及排尘口处的颗粒夹带返混现象。

基于ABAQUS的曳光管套结构设计与强度分析

曳光弹丸发射过程中,在高过载和高膛压作用下曳光管壳可能发生大的塑性变形甚至断裂,影响曳光药剂正常燃烧,因此设计了用来固定和保护曳光管的管套。压螺与弹体螺纹连接和曳光管壳在高过载作用下的强度校核结果满足要求的前提下,利用ABAQUS软件仿真分析曳光管壳和管套在360 MPa膛压作用下的应力应变,结果显示:曳光管与方案1管套配合时的最大应力为1026 MPa,最大应变为0.8;与方案2管套配合时的最大应力为844.7 MPa,最大应变为0.05。经分析可知,采用方案1管套时,曳光管壳的局部变形量可使曳光药剂断层、松散;而采用方案2管套时,曳光药剂强度不会发生破坏性变化。通过曳光性能射击试验验证了ABAQUS软件仿真分析结果。