板式换热器混装阻力降测试与计算方法研究

鉴于板式换热器冷热两侧测试阻力降有一定差别,提出评价板式换热器阻力降性能的理论阻力降。考虑到测试水温对物性参数的影响,将理论阻力降转化为定性温度为40℃时的阻力降进行数据分析。通过对数据进行无量纲分析,提出计算板式换热器混装阻力降的三种回归模型即一次、二次、三次回归方程模型。计算结果表明:二次回归方程回归效果最好,精度最高。以试验测试数据为基础,通过理论推导,得出计算板式换热器混装阻力降的一个通用计算方法,即用一个拟合关系式来计算板式换热器混装阻力降。计算数据与试验数据对比表明:拟合关系式计算误差不超过5%,说明了此方法的正确性。     

钎焊板式换热器传热与压降性能实验

钎焊板式换热器具有高效、紧凑、节能、节材且密封性好等特点受到许多行业的青睐.文中介绍对钎焊板式换热器进行的水-水传热性能实验和根据实验结果测得的传热系数和压降的性能曲线.     

波纹板式换热器传热与流动特性分析

通过数值模拟的方式,对一种用于低粘度流体的波纹板式换热器的传热特性和阻力性能进行分析,以控制变量法分析了流体速度对传热特性及阻力性能的影响;搭建了板式换热器测试平台,验证了数值模拟结果的正确性和可行性;用等速法拟合了Nu-Re与Eu-Re的相关准则式,并采用JF因子评价换热器综合性能。结果表明：模拟结果与实验结果相比误差在10%以内;当流体流速小于1.0 m/s时,换热器传热系数和压降随着流速的增大而增大,但综合换热性能逐渐变差,在此流速范围内,总传热系数随冷流体进口温度升高而增大。     

低Re下板式换热器性能的实验研究及热力学分析

实验测定了两种不同板式换热器在低Re条件下(200相似文献   

蒸发冷却板式换热器的传热与阻力实验研究

通过对板式换热器传热的理论分析和在干工况、喷淋工况下的实验研究,得出板式换热器在喷淋情形下空气侧喷淋水量对强化对流传热系数的影响关系,进而拟合出喷淋情形下空气侧的对流传热系数的关联式。同时为了综合考虑由于喷淋造成的换热器性能的变化,还对喷淋前后空气侧的阻力变化进行了测试分析。     

板式换热器传热和阻力特性的实验研究

利用搭建的液-液型板式换热器试验平台,根据实验数据运用定性雷诺数法拟合出传热关联式,找出Nu与摩擦因子f之间的通用关系式,为板式换热器的设计计算提供了依据。运用传热量与功率的消耗比来评价板式换热器的性能,找出了影响其性能的主要因素,进一步澄清了单纯依靠提高流速来增加传热性能是不经济的。     

烟气脱硫系统中热管式换热器流动阻力计算

热管换热器的阻力降问题涉及到其研发、设计、应用以及防腐措施等方面,是热管式换热器研究的一个重要方面。文章尝试使用换热器局部数值模拟、宏观多孔介质模拟以及传统经验公式,用三种不同的计算方法对换热器的流动阻力进行计算,并对其结果进行比较和相互验证,较全面地描述热管式换热器宏观和局部的流动阻力场,为包括脱硫腐蚀研究在内的有关热管换热器的进一步研究提供参考。     

高效节能BB型不等截面板式换热器的开发与应用

高效节能ＢＢ型不等截面板式换热器的开发与应用吉林省四平师范学院姜守霞吉林省四平九圆热交换设备制造公司１前言板式换热器具有传热效率高、结构紧凑、占地面积小、操作灵活、安装拆洗方便等优点。因此，广泛用于化工、石油、冶金、机械、电力、动力、集中供热、轻工、...     

Effect of the plate thermal resistance on the heat transfer performance of a corrugated thin plate heat exchanger

Two‐dimensional conjugate conduction/convection numerical simulations were carried out for flow and thermal fields in a unit model of a counter‐flow‐type corrugated thin plate heat exchanger core. The effects of the thermal resistance of the solid plate, namely the variation of the plate thickness and the difference of the plate material, on the heat exchanger performance were examined in the Reynolds number range of 100<Re<400. Higher temperature effectiveness was obtained for a thicker plate at any Reynolds number, which was a unique feature of corrugated thin plate geometry. Detailed discussions on the thermal fields revealed that restricting the heat conduction along the plate by making the plate thinner or choosing a low thermal conductivity material causes a larger plate temperature variation along the plate, and, consequently, a smaller amount of thermal energy exchanged between two fluids. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(3): 209–223, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20110     

同轴径向热管换热器壳程流场数值模拟

基于多孔介质模型和分布阻力方法,引入Al-sanea和Taborek两种阻力关系式模拟同轴径向热管换热器壳程的流场。结果表明:换热器壳程静压沿烟气流动方向呈线性分布;随入口烟气速度的增加,换热器阻力损失增大、压降增大;且随入口烟气速度的增加,压降增加的速率增大。     

Development of gas-solid direct contact heat exchanger by use of axial flow cyclone

A heat exchanger between particulate or granular materials and gas is developed. It makes use of a swirling gas flow similar to the usual cyclone separators but the difference from them is that the swirl making gas is issued into the cyclone chamber with downward axial velocity component. After it turns the flow direction near the bottom of the chamber, the low temperature gas receives heat from high temperature particles supplied from above at the chamber's center. Through this configuration, a direct contact and quasi counter-flow heat exchange pattern is realized so that the effective recovery of heat carried by particles is achieved. A model heat exchanger was manufactured via several numerical experiments and its performances of heat exchange as well as particle recovery were examined. Attaching a small particle diffuser below the particle-feeding nozzle brought about a drastic improvement of the heat exchange performance without deteriorating the particle recovery efficiency. The outlet gas temperature much higher than the particle outlet temperature was finally obtained, which is never realized in the parallel flow heat exchanger.     

一种新型换热器流动特性的实验研究

螺旋折流板换热器是将折流板布置成与管束有某个倾斜角度 ,流体在壳程沿着螺旋折流板呈螺旋状流动的一种新型换热器。在对几个影响螺旋折流板换热器流动特性的因素进行了实验研究后 ,本文对实验结果进行了论述和分析。     

Experimental Study on Heat Transfer and Pressure Drop Characteristics of Four Types of Plate Fin－and－TUbe Heat Exchanger Surfaces

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The control of a refrigeration system using a compact plate heat exchanger as an evaporator

This paper will show some of the problems that may be encountered when using a compact plate exchanger as an evaporator in a refrigeration system which utilizes a thermostatic expansion valve as its controlling device.     

Numerical studies on flow and heat transfer in membrane helical-coil heat exchanger and membrane serpentine-tube heat exchanger

The flow and heat transfer characteristics of synthesis gas (syngas) in membrane helical-coil heat exchanger and membrane serpentine-tube heat exchanger under different operating pressures, inlet velocities and pitches are investigated numerically. The three-dimensional governing equations for mass, momentum and heat transfer are solved using a control volume finite difference method. The realizable k-ε model is adopted to simulate the turbulent flow and heat transfer in heat exchangers. There flows syngas in the channels consisting of the membrane helical coils or membrane serpentine tubes, where the operating pressure varies from 0.5 to 3.0 MPa. The numerically obtained heat transfer coefficients for heat exchangers are in good agreement with experimental values. The results show that the syngas tangential flow in the channel consisting of membrane helical coils is significant to the heat transfer enhancement to lead to the higher average heat transfer coefficient of membrane helical-coil heat exchanger compared to membrane serpentine-tube heat exchanger. The syngas tangential velocity in the membrane helical-coil heat exchanger increases along the axial direction, and it is independent of the gas pressure, increasing with the axial velocity and axial pitch rise and decreasing with the radial pitch rise.     

Influence of nanofluids on parallel flow square microchannel heat exchanger performance

The effects of using various types of nanofluids and Reynolds numbers on heat transfer and fluid flow characteristics in a square shaped microchannel heat exchanger (MCHE) is numerically investigated in this study. The performance of an aluminum MCHE with four different types of nanofluids (aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), silver (Ag), and titanium dioxide (TiO₂)), with three different nanoparticle volume fractions of 2%, 5% and 10% using water as base fluid is comprehensively analyzed. The three-dimensional steady, laminar developing flow and conjugate heat transfer governing equations of a balanced MCHE are solved using the finite volume method. The MCHE performance is evaluated in terms of temperature profile, heat transfer rate, heat transfer coefficient, pressure drop, wall shear stress pumping power, effectiveness, and overall performance index. The results reveal that nanofluids can enhance the thermal properties and performance of the heat exchanger while having a slight increase in pressure drop. It was also found that increasing the Reynolds number causes the pumping power to increase and the effectiveness to decrease.