共查询到19条相似文献,搜索用时 187 毫秒
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折流杆冷凝器是一种新型的管壳式换热器.本文针对折流杆冷凝器的结构特点,提出了折流杆冷凝器壳侧混合蒸气冷凝传热的计算方法,并通过实验加以验证.实验用折流杆冷凝器有两台:一是圆型结构,含折流圈9个、换热管37根,管尺寸φ19×2mm; 另一是矩形结构,含折流圈10个、换热管14根,管尺寸φ25×2.5mm,壳体前侧板设有五块直径为100mm的视镜,以观察冷凝流型.实验用工作介质为乙醇-水、溶剂汽油和溶剂汽油-氮气.在重力控制区和过渡区,实验所得传热系数值与理论计算值的偏差均小于32%. 相似文献
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折流杆冷凝器是一种新型的管壳式换热器.本文针对折流杆冷凝器的结构特点,提出了折流杆冷凝器壳侧混合蒸气冷凝传热的计算方法,并通过实验加以验证.实验用折流杆冷凝器有两台:一是圆型结构,含折流圈9个、换热管37根,管尺寸φ19×2mm; 另一是矩形结构,含折流圈10个、换热管14根,管尺寸φ25×2.5mm,壳体前侧板设有五块直径为100mm的视镜,以观察冷凝流型.实验用工作介质为乙醇-水、溶剂汽油和溶剂汽油-氮气.在重力控制区和过渡区,实验所得传热系数值与理论计算值的偏差均小于32%. 相似文献
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帘式折流片换热器强化传热数值研究 总被引:1,自引:0,他引:1
为解决折流板换热器壳程流体阻力过大和折流杆换热器低Re下传热系数较小等管壳式换热器的不足,提出了壳程流体"斜向流"的新概念,研制了新型高效节能管壳式换热器?帘式折流片换热器,其壳程传热系数高于折流杆换热器20%~30%,而壳程压力损失大幅低于折流板换热器。以场协同原理分析了斜向流的强化传热机理,指出在帘式折流片换热器壳程中流体速度场与温度梯度场间的夹角小于折流杆换热器,是其强化传热的重要原因。对帘式折流片换热器中折流栅间距、折流片倾角、折流片宽度等重要几何参数对传热和压降的影响规律进行了数值模拟研究,并据此推导了壳程传热系数和流体阻力降准数关联式,为其工程设计和推广应用提供了参考依据。 相似文献
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螺旋折流板冷凝器壳程传热性能的实验研究 总被引:1,自引:0,他引:1
对螺旋角为25、30、40°的螺旋折流板冷凝器壳程传热性能和压降性能进行实验测试,40°螺旋角的螺旋折流板冷凝器的综合传热性能要优于25、30°螺旋折流板冷凝器的,40°有泄流槽螺旋折流板冷凝器的传热综合性能又优于不开槽螺旋折流板冷凝器的。 相似文献
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对自支撑型扭曲管中冷器壳程传热与压降性能进行了实验研究,结合实验室先前扭曲管单管实验的数据,通过与相同工况条件下的折流板中冷器和折流杆中冷器管、壳程传热与压降性能以及综合性能的对比,分析自支撑型扭曲管中冷器的强化传热特性。研究结果表明:在测量范围内,自支撑型扭曲管中冷器管程传热性能相比其他2种中冷器平均提高21.3%;壳程传热性能相比折流杆中冷器,平均提高20.6%;壳程压降相比折流杆中冷器,平均降低89.4%,相比折流板中冷器,平均降低93.9%。与传统中冷器相比,自支撑型扭曲管中冷器既有折流板中冷器传热效率高的优点,又有折流杆中冷器压降损失小的优点,在工业领域中,有很好的应用前景。 相似文献
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对于管内凝结而言,为保持蒸汽在换热管进口段的高效换热状态而进行中间分液,改变气液两相流的流型,以保持相对较高的换热系数是"短管效应"理论的技术举措。结合传统冷凝器的结构,本文设计了一种用于实验研究的气液分离卧式管壳式水冷冷凝器。通过布置在冷凝器两端分程隔板处的不同直径和数量的分液管来观察其换热效果,并与传统冷凝器进行整体换热系数、出口冷凝液温度及压力损失三方面的实验对比。结果表明:具有不同直径和数量的分液管的冷凝器具有相似的热力性能;具有不同直径和数量的分液管的冷凝器整体换热系数比传统冷凝器要高,出口冷凝液温度比传统冷凝器要低,且具有较小的压力损失;在测试工况下,右侧开启1个0.5mm、1个1mm,左侧开启2个1mm、1个0.5mm分液管的冷凝器表现出较好的综合换热性能。 相似文献
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管壳式冷凝器工艺设计浅析 总被引:2,自引:0,他引:2
胡骏 《硫磷设计与粉体工程》2003,(6):25-27
综述了管壳式冷凝器的流体力学基础和工艺设计参数的选择,介绍了冷凝器材质和换热介质及走向的选择;阐明了提高传热系数、降低换热面积是冷凝器工艺设计的最终目标;结合某工程项目,运用HTFS软件进行计算选型,生产结果表明选用效果良好。 相似文献
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An analysis is presented for the main factors which control the intensity of vapor condensation in plate condenser channels, such as heat transfer both in single-phase stream of the coolant and in the condensate film, heat and mass transfer in gas-vapor phase, thermal resistance of fouling at heat transfer surface and pressure drop in condensing stream. On the basis of a relationship between the heat transfer and the wall shear stress, an approximate equation is obtained for calculating heat transfer from the pressure drop data. For calculation of heat transfer in condensate film during the condensation of high speed vapor, an analogy between heat and momentum transport has been used. An analysis of fouling deposition on heat transfer surface has been performed and an equation is presented for calculating the reduction of the fouling thermal resistance as compared with shell and lube heat exchangers. Experimental data are in good agreement with theoretical results. These data have shown the improvement of all the mentioned factors, which determine the intensity of the whole condensation process compared to the same factors in shell and tube condensers. Under the equal conditions, the required area of the heat transfer surface is reduced by 1.6 to 3 limes for the plate condenser, as compared with conventional shell and tube units. 相似文献
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An analysis is presented for the main factors which control the intensity of vapor condensation in plate condenser channels, such as heat transfer both in single-phase stream of the coolant and in the condensate film, heat and mass transfer in gas-vapor phase, thermal resistance of fouling at heat transfer surface and pressure drop in condensing stream. On the basis of a relationship between the heat transfer and the wall shear stress, an approximate equation is obtained for calculating heat transfer from the pressure drop data. For calculation of heat transfer in condensate film during the condensation of high speed vapor, an analogy between heat and momentum transport has been used. An analysis of fouling deposition on heat transfer surface has been performed and an equation is presented for calculating the reduction of the fouling thermal resistance as compared with shell and lube heat exchangers. Experimental data are in good agreement with theoretical results. These data have shown the improvement of all the mentioned factors, which determine the intensity of the whole condensation process compared to the same factors in shell and tube condensers. Under the equal conditions, the required area of the heat transfer surface is reduced by 1.6 to 3 limes for the plate condenser, as compared with conventional shell and tube units. 相似文献
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将平均孔径5、20和50 nm的管式陶瓷外膜制成膜冷凝器,并搭建膜面积0.3 m2的膜冷凝中试实验装置,开展陶瓷膜冷凝器在烟气水、余热资源回收及脱白烟领域的中试研究。对比采用不同排布方式的两级陶瓷膜冷凝器的水、热回收效果,考察进气相对湿度、进气温度、进气线速度等操作条件和不同孔径陶瓷膜的排布方式对膜冷凝器水通量及水回收率的影响。研究表明,在两级膜冷凝器中,烟气、冷却水均为串联流动时,可得到更高的水、热通量及回收率。过程水通量随进气相对湿度、进气温度、进气线速度的增加而增加;水回收率随进气相对湿度、进气温度的增加而增加,随着进气线速度的增加而降低。在三级膜冷凝器中,采用每级均填充平均孔径50 nm的管式陶瓷外膜的排布方式时,可获得最佳的水、热回收效果;不同孔径陶瓷膜的排布方式对膜冷凝器水回收效果影响明显,对热回收效果影响不大。在各实验工况下,三级膜冷凝器水通量及水回收率最高分别可达38.5 kg·m–2·h–1和50.6%。与传统换热器相比,陶瓷膜冷凝器不仅可实现水、余热的同时回收,且其总传热系数为415 W·m–2·℃–1,换热效果更佳,并能明显缓解“白色烟羽”等视觉污染。基于陶瓷膜的膜冷凝技术在中试实验阶段展现出良好的回收效果,在资源回收及脱白烟过程有广阔的应用前景。 相似文献
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冷凝传热广泛存在于各种冷凝器中,传统冷凝管内厚液膜将蒸汽与冷壁面隔开,是恶化冷凝传热的根本原因。提出采用非能动相分离概念,在冷凝管内设置柱状金属丝网,管壁与丝网之间形成环形间隙。液体在表面张力作用下被捕获到丝网内,气相在环隙内流动,使气液相分布与传热协同。为验证这一新颖学术思想,开展空气-水两相流实验,获得相分离概念调控水平管内分层流实验结果。发现当水平管内具有一定液位高度时,全部液体被捕获到网内流动,管壁完全被气相覆盖,实现“气托液”模式。水平管内液位较低时,部分液体被捕获至丝网内,气相与管壁接触面积增大。按以上相分离方法对分层流的调控,在发生冷凝传热时,预期可实现高强度冷凝传热。 相似文献
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The heat transfer and pressure drop in a thermoplate heat exchanger operating as a condenser have been investigated experimentally. In order to separate the heat transfer resistances in the condensation process, the single phase forced convection has been studied using distilled water and Marlotherm oil in the thermoplate and correlations developed for the Nusselt number and the friction factor. For the condensation experiments, an apparatus has been constructed comprising two identical condensers composed of the same thermoplate type as employed in the single phase experiments. Isopropanol is used as a test fluid at pressures below atmospheric pressure. The heat transfer resistances in the condensation experiments are separated and expressions for the condensation heat transfer and pressure drop are developed with the aid of the results obtained in the single phase studies. 相似文献
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The condensation heat transfer in the inclined reflux condensers is investigated at various inclinations. A condensation heat transfer model is set up. The calculated values of the model agree well with the experimental data. Both the experimental data and the theoretical calculations show that the condensation heat transfer coefficient in the inclined reflux condensers varies with the inclinations and will be maximum when the inclination angle is about 10°. 相似文献