水平管式降膜蒸发器布液器的方案比较

介绍降膜蒸发器原理及其核心部件一一布液器,并通过流场模拟与理论分析,总结3种布液器方案的优缺点,为研发及生产提供参考。     

排液蒸发设备的设计及选型

妥善处理空分设备冷箱出来的纯度不高的液体和空分设备停车时精馏塔底部积累的大量液体,是空分设备安全运行的影响因素之一。分析了当前空分设备中各种类型排液蒸发设备的设计和结构特征,从安全、能耗、处理能力、运行成本和可靠性等角度,提出新建空分设备中排液蒸发设备的选型、设计建议。     

重力热管蒸发段气液分布形式与换热能力分析

重力热管传热性能主要取决于蒸发段内液膜与液池的分布形式和换热过程.提出了许多液膜和液池换热机理与其影响因素之间的经验关联式.利用其中较完善的理论结果,总结了两者的换热机理分布图,通过计算传热系数的比值,发现在满足管内气液循环条件下,增加蒸发段内液膜段长度可以提高热管传热性能.     

环保型风扇式排液蒸发器的设计

介绍用于空分设备低温液体混合物排放的风扇式排液蒸发器的结构形式、参数计算和管道设计。阐述为降低运行时风机产生的噪声而采取的优化排放措施及其效果。     

Design of a plate-type evaporator for heat pumps

Use of particularly cold and/or polluted water as a heat source for heat pumps makes special demands on evaporator design. The plate-type evaporator is probably the most suitable design. It can be cleaned easily and ice formation does not cause any damage to it. High plate efficiency is attained by using narrow, vertical refrigerant flow channels. On the water side falling film flow is recommended. Under such conditions, evaporator k-values of up to approximately 1400 W m⁻² K⁻¹ and 1200 W m⁻² are reached in laboratory tests, using refrigerant R 22 and R 12 respectively. Experiments have shown that water of 2°C and even lower temperatures may be used. This opens for use significant heat sources, which probably could not be exploited economically with other evaporator types.     

空调用翅片管式蒸发器的模拟与分析

建立R410A翅片管式蒸发器的稳态分布参数模型,分析制冷剂侧换热、压降、温度和干度沿流程的分布情况,并讨论风量、制冷剂流量及翅片管结构形式对蒸发器换热和流动性能的影响,为翅片管式蒸发器的设计和性能优化提供理论依据。     

蒸发器稳态仿真的一种改进算法

对蒸发器进行仿真研究,改进换热过程中温差的计算方法,提出新的程序算法。通过对仿真结果的定性分析验证该方法的可行性。     

水平管降膜式蒸发器管间流动模式的研究

对应用于空气调节和制冷方面的水平管降膜式蒸发器原理进行简述，在分析设计水平管降膜式蒸发器时，需要考虑制冷剂在水平光管上流动模式。给出影响制冷剂在水平光管上流动模式的关键参数。     

板式升膜蒸发器蒸发换热特性的实验研究

升膜蒸发利用被蒸发溶液在受热沸腾汽化产生的蒸气带动料液上升,形成一个稳定的液膜,从而加快蒸发,提高了传热系数.针对蒸发器液位、换热温差、加热蒸气的流量等因素对板式升膜蒸发传热系数的影响进行了实验研究,实验结果表明随着蒸发器内液位的降低升膜蒸发传热系数明显提高,此外,换热温差、加热蒸气的流量等因素对升膜蒸发换热性能也有明...     

移动式空调机蒸发器冷凝水的利用

对如何利用移动式空调机蒸发器产生的冷凝水进行分析,探讨提升移动式空调机能效比的一种改进方法。     

An experimental investigation of capillary breakup of a liquid metal jet

The limits of influence of oxidation on the capillary breakup of a liquid metal jet is investigated. It is shown that in a region of weak oxidation the disruption of the jet proceeds as is usual for a Newtonian fluid.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 60, No. 4, pp. 554–557, April, 1991.     

多楔带附件驱动系统旋转振动方程的通程式方法

建立了单根多楔带附件驱动系统的旋转振动方程的通程化方法,以适用于不同布置形式的单根多楔带附件驱动系统的旋转振动特性计算。在此基础上,开发了一个单根多楔带附件驱动系统旋转振动特性的计算程序,并利用该程序对两个不同布置形式的多楔带附件驱动系统的旋转振动特性进行了计算。计算得到了这两个不同布置形式的多楔带附件驱动系统的固有频率、带的稳态张力、轮和张紧臂的角度波动、带段的动态张力和最大轮毂载荷等。将部分计算值和实测值进行对比,验证了本文所建立的通程式方法的可行性。     

降膜式蒸发器管束间流量分配均匀性对其性能的影响

通过模拟计算讨论降膜式蒸发器在运行过程中,换热管束内外流体不均匀分布对换热器整体性能的影响。管外性能的模拟计算采用根据管束中换热管位置、沿换热管束长度方向上网格离散的三维网格格式,管内性能的计算采用三维CFD计算方式。计算和分析表明,换热流体在换热器中的分布均匀性对换热器内管外局部干斑出现的比例,以及整体性能有明显的影响。     

空分设备低温残液蒸发设备的选用

文章介绍和分析了当前空分设备中低温残液蒸发设备的类型及特性，并对各类残液蒸发设备进行了综合分析和比较。提出了低温残液蒸发设备设计和使用时应注意的问题。     

空分设备低温残液蒸发设备的选用

文章介绍和分析了当前空分设备中低温残液蒸发设备的类型及特性,并对各类残液蒸发设备进行了综合分析和比较,提出了低温残液蒸发设备设计和使用时应注意的问题。     

两段式喷嘴引射器及其引射制冷系统性能实验研究

对采用两段式喷嘴引射器的两相流引射制冷系统进行了实验研究,并将两段式喷嘴的引射比及其系统COP分别与拉法尔喷嘴引射器的引射比及其系统COP进行了比较。实验结果表明：在冷凝/蒸发温度为45 ℃/1 ℃工况下,使用不同几何尺寸两段式喷嘴引射器的引射比均大于拉法尔喷嘴引射器的引射比,最大提高了约18%;使用两段式喷嘴引射器的制冷系统COP大于使用拉法尔喷嘴引射器的制冷系统COP,最大提高了约12%;在蒸发温度为1 ℃条件下,两段式喷嘴引射器及拉法尔喷嘴引射器的引射比均在冷凝温度为45 ℃时达到最大值,而在冷凝温度为50 ℃条件下,两种引射器的引射比均在蒸发温度为3 ℃时达到最大值。     

基于AMESim的液氮可控传输性能分析

针对超低温冷却加工液氮可控传输难题,分析了热流量、管路压降等复杂因素对液氮可控传输的影响机制,提出了基于AMESim的液氮可控传输性能分析方法,建立了受热管道液氮两相流动传热数值模型,并在此基础上,研制出一套液氮可控传输原理性系统。通过对比实验表明,提高系统的输入压力能够增大低温流体的流量,缩短系统进入热平衡状态的时间,提高输出流体的干度和流型的稳定性;研制出的液氮可控传输原理性系统在输入压力为1.3 MPa时,在一定的开口范围内,能够稳定输出流量可控的低干度流体,且符合超低温冷却加工的要求。     

An experimental study of the effects of surfactant on a falling liquid film

Addition of surface active agents to a falling liquid film changes the fluid mechanical behavior of the film. In this study we describe, both by observations and by calculations, what happens with the wave pattern after an addition of surfactant. The experiments were carried out in a 6-m high falling film column with a mixture of water and glycerol. The changes in wave pattern were detected by a video camera. Addition of surfactant will influence the film differently for different surfactant concentrations. Surfactant concentrations under the saturation limit destabilize the film and concentrations over the limit stabilize the film. The surface excess concentration, the concentration of surfactant in the surface per square meter, plays a key role in the influence of surfactant on the behavior of falling liquid films.     

Design of a plate-type evaporator for heat pumpsConception d'un évaporateur à plaques pour pompes à chaleur

Use of particularly cold and/or polluted water as a heat source for heat pumps makes special demands on evaporator design. The plate-type evaporator is probably the most suitable design. It can be cleaned easily and ice formation does not cause any damage to it. High plate efficiency is attained by using narrow, vertical refrigerant flow channels. On the water side falling film flow is recommended. Under such conditions, evaporator k-values of up to approximately 1400 W m^?2 K^?1 and 1200 W m^?2 are reached in laboratory tests, using refrigerant R 22 and R 12 respectively. Experiments have shown that water of 2°C and even lower temperatures may be used. This opens for use significant heat sources, which probably could not be exploited economically with other evaporator types.     

Numerical investigation of supercritical LNG convective heat transfer in a horizontal serpentine tube

The submerged combustion vaporizer (SCV) is indispensable general equipment for liquefied natural gas (LNG) receiving terminals. In this paper, numerical simulation was conducted to get insight into the flow and heat transfer characteristics of supercritical LNG on the tube-side of SCV. The SST model with enhanced wall treatment method was utilized to handle the coupled wall-to-LNG heat transfer. The thermal–physical properties of LNG under supercritical pressure were used for this study. After the validation of model and method, the effects of mass flux, outer wall temperature and inlet pressure on the heat transfer behaviors were discussed in detail. Then the non-uniformity heat transfer mechanism of supercritical LNG and effect of natural convection due to buoyancy change in the tube was discussed based on the numerical results. Moreover, different flow and heat transfer characteristics inside the bend tube sections were also analyzed. The obtained numerical results showed that the local surface heat transfer coefficient attained its peak value when the bulk LNG temperature approached the so-called pseudo-critical temperature. Higher mass flux could eliminate the heat transfer deteriorations due to the increase of turbulent diffusion. An increase of outer wall temperature had a significant influence on diminishing heat transfer ability of LNG. The maximum surface heat transfer coefficient strongly depended on inlet pressure. Bend tube sections could enhance the heat transfer due to secondary flow phenomenon. Furthermore, based on the current simulation results, a new dimensionless, semi-theoretical empirical correlation was developed for supercritical LNG convective heat transfer in a horizontal serpentine tube. The paper provided the mechanism of heat transfer for the design of high-efficiency SCV.