不锈钢波纹管强化传热机理分析及在换热器中的应用

新型不锈钢波纹管是选用特种不锈钢板材,滚压卷成几种规格圆形薄壁光管,将焊缝错开套装成多层薄壁圆形光管,再经特殊工艺涨波凸起成型的多层波纹管。该波纹管的管内流动呈等直径流束型式和弧形流束型式,使流速和压力周期性的变化,冷热流体产生强烈扰动,实现了复合强化换热。本文在水-水换热条件下,对该波纹管强化换热规律进行了实验研究,分析了新型波纹管的强化传热机理,并给出该管的优化尺寸范围,对新型不锈钢波纹管在换热器中的实际应用提供了理论依据。     

螺旋槽管凝结换热器的研究与应用

通过对螺旋槽管凝结换热器的试验研究,得到了螺旋槽管涉及相变时管内对流换热、管外凝结换热准则关联式以及管内流动阻力关联式,并依据试验结果,将螺旋槽管应用于电站凝结换热器,取得了满意的效果。     

Numerical study on heat transfer characteristics of double tube heat exchangers with alternating horizontal or vertical oval cross section pipes as inner tubes

In this paper, a numerical study on the flows in parallel and counter flow double tube heat exchangers with the inner tubes being either alternating horizontal or vertical oval cross section pipes or circular pipes is presented. The results include temperature and pressure contours and velocity vectors at several selected cross sections, axial averaged Nusselt number distributions and distributions of overall heat transfer coefficient and heat transfer enhancement factor versus three different parameters. The computation shows that the introduction of the inner alternating oval tube produces axial vortices in both the inner and outer tube flows, and the tube’s heat transfer performance is improved as a result. In general, the counter flow arrangement returns a higher level of overall heat transfer coefficient than the parallel flow arrangement. However, in terms of the magnitude of heat transfer enhancement, the performance of the parallel flow arrangement is slightly better than that of the counter flow.     

于海鲜酱杀菌的折流板波纹管换热器传热与流动性研究

为了开发用于液体食品杀菌的新型换热器,通过实验研究了螺旋折流板波纹管换热器用于海鲜酱杀菌过程中的传热与流动性能。研究结果表明:在水-海鲜酱的热交换中,螺旋折流板波纹管换热器总传热系数比波纹管换热器提高了10%～50%,比光管换热器提高了30%～130%;管侧海鲜酱综合性能系数α/Δp值波纹管大于光管,壳侧水的综合性能系数α/Δp值螺旋折流板波纹管结构换热器比波纹管结构的和光管结构的都大,证明了螺旋折流板波纹管换热器用于液体食品杀菌具有良好的应用前景。     

双管程热交换器换热特性研究

通过对双管程热交换器结构和工作原理介绍,利用经典对流换热理论,采用定性判断和定量比较的方法,分析双管程热交换器与管壳式换热器的换热能力。对双管程热交换器而言,换热能力上,竞争优势明显;流动阻力上,无明显优势。在低品位能源余热利用方面,对深化双管程热交换器的研究,优化设备结构、降低成本有一定意义,值得工程技术人员借鉴与参考。     

电站锅炉空气预热器改造方案研究

根据低温腐蚀、漏风等原因造成所回围蓄热式空气预热器运行不良,电站锅炉出力不足等问题,文中通过对提出的几种改造方案的比较,论证了利用螺纹管、热管强化传热技术,采用复合式空气预热器对原有空气预热器进行技术改造的可行性。     

波纹管换热器管束支撑结构

根据各种管束支撑结构的特点,找出与之相适应的波纹管管型,分析不同的组合结构对波纹管换热器壳程性能的影响,指出对波纹管换热器进行优化设计和实现整体强化传热的途径。     

余热锅炉管口区传热的数值分析

应用高温换热设备管口传热分析系统针对某天然气化工厂二次转化气余热锅炉管口区传热问题建立了物理、数学模型,进行了相应的数值分析。数值计算结果表明,新型双瓷管保护结构改善了管口区的传热性能。降低了余热锅炉管口区金属材料的温度,减缓了高温腐蚀反应速度;新型双瓷管保护结构同时改善了管口区域内保护套管的温度“畸变”,因而减轻管口区材料的热应力破坏。     

复合相变换热技术在锅炉排烟余热回收中的应用

复合相变换热技术是一种回收锅炉排烟余热的新型技术,其壁温可控可调,具有防止烟气侧低温腐蚀的突出优势.介绍了宝钢采用该技术回收利用本厂内一台低压锅炉排烟余热生产生活热水的节能项目,该项目于2013年5月投运,至今运行良好.运行结果表明,该复合相变换热器可使锅炉排烟温度由194℃降至138℃,同时获得90℃热水19.1 t·h-1.通过实施该节能项目可回收烟气余热约1 400 k W,年节约标准煤约1 300 t,推进了宝钢节能减排.     

关于螺纹烟管的传热计算

十几万台新型水火管锅炉的螺纹烟管传热计算用"哈工大-之光所"的计算公式,试验及运行已表明公式的正确性.分析和讨论了有关资料推荐的其它计算公式及热有效系数ψ的选取等问题.     

板翅式换热器在燃气轮机进气冷却系统中的应用

将板翅式换热器应用于吸收式燃气轮机进气冷却系统中，降低燃气轮机压缩机进口温度，提高燃气轮机高温条件下的出力，在国内尚无先例。针对板翅式换热器，简要介绍了结构、布置形式和性能。通过实测的运行数据，对板翅式换热器和管式换热器的性能进行了对比。结果表明：板翅式换热器在传热系数、体积、进气阻力等方面，性能优于管式换热器，是一种值得发展的换热设备。最后提出了该板翅式换热器在实际应用中存在的一些问题及对应的处理方法。     

干熄焦余热锅炉蒸发器频发爆管的机理分析及预防策略

针对某厂干熄焦（CDQ）余热锅炉蒸发器频发爆管现象,采用在线监测烟气温度和管壁温度的方法,通过对烟气侧换热和并联管组流量分配两方面进行深入分析,综合大量实际运行数据,发现集中发生在集箱三通附近部位的爆管主要原因是管壁超温所致。提出预防蒸发器爆管频发的关键措施。     

小型燃油锅炉螺纹管传热计算方法的选用

螺纹管的传热计算方法有多种,受螺纹管参数影响各种方法的计算结果差异较大。以小型燃油锅炉的螺纹管传热计算为例,选取\"哈工大-之光所\"、\"工业锅炉设计计算标准方法\"和日本吉富英明等人提出的公式三种传热计算方法,通过改变相对深度e/d和相对节距s/d进行传热计算,对比计算结果并分析讨论影响因素。结果表明:\"工业锅炉设计计算标准方法\"中螺纹管总传热系数误差大于10%,不建议选用;日本吉富英明等人的方法不适用e/d0.042 1且s/d0.736 7的螺纹管传热计算;\"哈工大-之光所\"方法最适合小型燃油锅炉的螺纹管传热计算。     

电站锅炉新型烟气余热回收技术及经济性分析

为解决某300 MW火力发电厂循环流化床锅炉排烟温度偏高的问题,提出将传统低压省煤器与卧式相变换热器相结合的新型烟气余热回收技术.该技术不仅能预防换热设备酸腐蚀,还能实现电厂烟气深度余热回收节能.给出了系统的具体布置方案和设计参数,分析了系统对凝汽器真空以及引风机性能的影响,并应用等效焓降理论及节能定量分析理论进行理论计算.计算结果表明,采用该系统后,锅炉排烟温度降低45℃,降低标准煤耗近3.5 g/（kW·h）.     

CFD在碱回收锅炉改造中的应用

在北美，计算流体力学（CFD）正大量应用于各类锅炉的设计和改造。文章介绍了CFD模拟在碱回收锅炉改造中的应用，通过计算机模拟以改进碱回收锅炉燃烧空气系统，可以提高锅炉的出力和效率、改善过热器的积灰、节省改造成本，减少了资金浪费和停工检修的风险，具有显著的经济效益。     

On the steady‐state modelling of a two‐stage evaporator system

We develop and validate against experimental measurements a steady‐state two‐stage flooded refrigerant evaporator model for a heat pump drying system. A prototype two‐stage heat pump dryer test facility was designed, built and instrumented to provide the required measurements for the validation of the model. Repeatability and data quality tests were conducted to evaluate the accuracy of measurements. Experimental data could be reproduced to within ±6.5 per cent of replicated air and refrigerant side measurements for the same evaporator's air inlet conditions while the discrepancy of energy balance at the air‐side and refrigerant‐side was observed to be within ±8.9 per cent. The two‐stage evaporator model predicted the air‐side total heat and latent heat transfer of the two‐stage evaporator to within (?6.3 per cent, 7.6 per cent) and (?11.5 per cent, 9.5 per cent), respectively. On the refrigerant‐side, the model enabled the calculation of the degree of superheat to within (?10.6 per cent, 1.7 per cent). The model has shown that there is significant improvement in the heat recovered from a two‐stage evaporator system compared to a single evaporator system. In addition, the model demonstrated that the improvement in total heat recovery could be as high as 40 per cent over its base‐value when the latent to total load at the two‐stage evaporator is increased. Copyright © 2001 John Wiley & Sons, Ltd.     

Heat transfer and pressure loss characteristics of a heat exchanger for recovering latent heat (effects of straight fin length and fin pitch on the heat transfer and pressure loss characteristics)

In recent years, the requirement for the reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. A latent heat recovery type heat exchanger is one of the effective methods for improving thermal efficiency by recovering latent heat. This paper describes the heat transfer and pressure loss characteristics of a latent heat recovery type heat exchanger having straight fins (fin length: 65 mm or 100 mm, fin pitch: 2.5 mm or 4 mm). These were clarified by measuring the exchange heat quantity, the pressure loss of the heat exchanger, and the heat transfer coefficient between the outer fin surface and gas. The effects of fin length and fin pitch on heat transfer and pressure loss characteristics were clarified. Furthermore, equations for predicting the heat transfer coefficient and pressure loss which are necessary for heat exchanger design were proposed. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 230– 247, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20153 Copyright © 2004 Wiley Periodicals, Inc.     

板壳式换热器金属腐蚀原因分析

介绍了300MW燃气-蒸汽轮机联合循环机组加热系统焊接型板壳式换热器的结构和运行情况,针对波纹换热板焊缝开裂及腐蚀问题,对换热板材质作了判断,确认为316L不锈钢;从裂纹分布及裂纹起源着手,对裂纹和撕裂部位进行了微观形貌观察和金属元素分析。分析认为在现有工作温度和氯离子含量等条件下,换热板应力腐蚀开裂的风险较小。换热器泄漏的主要原因是焊缝腐蚀和热应力相对集中。     

The heat transfer and pressure loss characteristics of a heat exchanger for recovering latent heat (the heat transfer and pressure loss characteristics of the heat exchanger with wing fin)

In recent years the requirement for reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. A latent heat recovery type heat exchanger is one of the effective methods of improving thermal efficiency by recovering latent heat. This paper described the heat transfer and pressure loss characteristics of a latent heat recovery type heat exchanger having a wing fin (fin pitch: 4 mm, fin length: 65 mm). These were clarified by measuring the exchange heat quantity, the pressure loss of heat exchanger, and the heat transfer coefficient between outer fin surface and gas. The effects of condensate behavior in the fins on heat transfer and pressure loss characteristics were clarified. Furthermore, the equations for predicting the heat transfer coefficient and pressure loss which are necessary in the design of the heat exchanger were proposed. ©2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(4): 215–229, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20154