共查询到18条相似文献,搜索用时 125 毫秒
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采用降膜蒸发技术的制冷用降膜蒸发器是各空调企业争相研究的新型制冷设备。本文采用分布参数法建立水平管降膜蒸发器管束换热模型,针对管束进行优化研究,研究表明:管程采用水平布置,在保证总布液量不变的前提下,加大第一管程区域的布液量同时减小相应值的第二管程布液量,合理调整布液量可改善整体换热状况;管程采用上下布置,在干涸现象严重区域进行补液,可有效改善干涸现象,并且补液量并非越大越好,在补液量增加到一定量时,整体换热效果达到最佳。本文的研究为水平管降膜蒸发器的设计提供理论指导,促进其在制冷空调领域的推广应用。 相似文献
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基于CFD数值模拟的板式换热器分配器性能研究 总被引:9,自引:0,他引:9
基于计算流体动力学(Computational fluid dynamics, CFD)数值模拟方法,对板式换热器分配器在单相流动和两相流动时的分配性能分别进行研究.把板式换热器在有、无分配器作用时的数值模拟结果作对比,定量分析分配器对板式换热器并联流道间流体流量均匀分配的作用;进一步分析换热器并联流道数、工作流体流量和进口干度(两相流动时)变化对分配器流动分配性能的影响.结果发现,分配器显著提高换热器流道间流体分配的均匀性;无论是单相流动还是两相流动,并联流道数对换热器流道间流动分配均匀性的影响要大于工作流体流量变化的影响;与单相流相比,两相流动时分配器的分配性能较差,在制冷系统中当板式换热器作蒸发器使用时,这将会降低换热器的换热性能.研究结果为进一步改进分配器结构,改善板式换热器流道间流动分配的均匀性提供必要的理论依据. 相似文献
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基于分布参数模型的水平管式降膜蒸发器模拟 总被引:4,自引:0,他引:4
建立水平管式降膜蒸发器蒸发换热的分布参数模型,考虑换热性能沿管子轴向、管排方向的变化,以及传热管发生干斑现象时对降膜蒸发的影响。对一降膜蒸发器的性能进行模拟分析,并考察管束布置、制冷剂液膜质量流量、管程布置以及满液位置对降膜蒸发器性能的影响。结果表明,计算结果和试验结果吻合良好,通过合理的设计管排方式和满液位置,可以减少或避免干斑现象的发生,提高降膜蒸发器性能。 相似文献
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冷冻站中采用蒸发器侧冷冻水系统变流量或常规的定流量系统的设计配置,对系统的运行能耗有着比较重要的影响。对于蒸发器侧冷冻水系统定流量和变流量的分析表明:一次泵变流量系统不仅可以节省系统的初投资和机房面积,做到冷冻水泵的节能运行,还可以减少冷水机组的全年运行时数,节省冷却水泵的运行时数和能耗。 相似文献
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介绍了组合式热管蒸发器结构和工作原理.分析了组合式热管蒸发器传热过程.进行了实验研究.对污水人口温度一定的情况下,不同的污水流量对组合式热管蒸发器冷侧传热系数、热侧传热系数和总传热系数的影响,热管冷侧传热系数和热管热侧换热系数对热管总传热系数的影响以及冷热侧换热面积对热管总传热系数的影响进行了研究. 相似文献
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Fluid flow and heat transfer on a falling liquid film with surfactant from a heated vertical surface
The addition of surface active agent to a falling liquid film affects the flow characteristics of the falling film. In this
study, the flow and heat transfer characteristics for a falling liquid film have been investigated by addition of the surfactant.
The falling liquid film was formed on a vertical flat plate. Contact angle of a liquid droplet above a plate surface can be
substantially reduced with an increase in the surfactant concentration. The results obtained indicate that not only the wetted
area of falling liquid film is increased but also the film thickness is decreased as the surfactant concentration is increased.
It is also found that heat transfer rate is significantly increased while the heat transfer coefficient is almost constant
value with an increase in the surfactant concentration at a given mass flow rate. 相似文献
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夹套对流传热分析设计 总被引:1,自引:0,他引:1
建立了整体夹套结构的计算流体力学、计算传热学和有限元分析模型 ,利用SIMPLE算法和有限单元法分别进行了流体 /结构耦合传热、应力计算和详细的传热分析设计 ,为类似工程复杂结构的分析设计提供了一种先进可靠的手段 相似文献
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Wu Shuang-Ying Cao Bao-Xi Xiao Lan Li You-Rong 《Journal of Mechanical Science and Technology》2012,26(3):973-981
By establishing an axial symmetric invariable temperature phase change interface model of porous wick evaporator based on
alkali metal thermal-to-electric converter (AMTEC), a parametric study has been implemented to explore the impact of effective
thermal conductivity model, working fluid, wick material, porosity and particle size of porous wick on the flow and heat transfer
characteristics. The results indicate that the inner surface temperature profile of wick is closely dependent on effective
thermal conductivity models; it is the minimum for series model while the highest for parallel model. The inner surface temperature
of wick with Na-K alloy as working fluid is obviously lower than that with sodium or potassium as working fluid. The wick
made of refractory ceramics makes the minimum of inner surface temperature, while the one with nickel appears the highest
temperature. Increasing the porosity can reduce the pressure drop in the wick, but also increases the temperature of evaporator. 相似文献
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Joon Hong Boo 《Journal of Mechanical Science and Technology》2000,14(1):121-129
The thermal performance of a flat evaporator for capillary pumped loop (CPL) applications was investigated. Two to four layers of coarse wire screen wicks were placed onto the heated surface to provide irregular passages for vapor flow. The evaporator and condenser were separated by a distance of 1.2 m and connected by individual liquid and vapor lines. The wall material was copper and the working fluid was ethanol. The experimental facility utilized a combination of capillary and gravitational forces for liquid return, and distribution over the evaporator surface. The tubing used for vapor and liquid lines was 9.35 mm or less in diameter and heat was removed from the condenser by convection of air. A heat flux of up to 4.9×104 W/m2 was applied to a flat evaporator having dimensions of 100 mm by 200 mm, 20 mm thick. The thermal resistance of the system as well as the temperature characteristics of the system was investigated as the evaporator heat flux and the condenser cooling capacity varied. The performance of the evaporator and effect of condenser cooling capacity were analyzed and discussed. 相似文献
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基于SolidWorks的薄膜蒸发器三维参数化设计 总被引:3,自引:0,他引:3
随着三维CAD技术的发展,二维绘图已无法满足大部分客户的要求。在自行开发的薄膜蒸发器二维参数化设计系统的基础上,通过VisualBasic语言对SolidWorks软件进行二次开发,实现了薄膜蒸发器三维参数化设计及其虚拟装配设计。三维参数化技术的应用不仅提高了薄膜蒸发器的设计水平,缩短了开发周期,并为其进一步结构优化分析奠定基础。 相似文献