Changes in optimal design of a dry-expansion evaporator when replacing R22 with R407C: Différences de configuration optimale pour un évaporateur à détente sèche lors du remplacement du R22 par le R407C

An investigation was made on whether the optimal number of tubes in a dry-expansion evaporator, for a given area or a given cost, will change when R22 is replaced with the non-azeotropic mixture R407C. A comprehensive computer program was used to simulate the tube-and-shell evaporator, under several sets of conditions. The simulations show that there are only small differences between R22 and R407C in the optimal number of tubes. However, the results indicate that one can allow a somewhat higher pressure drop for R407C, and that the number of tubes for a given area therefore can be smaller when R407C is used. For both fluids, the evaporator performance is more sensitive to the optimization for a given cost than for a given area.     

A general dynamic simulation model for evaporators and condensers in refrigeration. Part II: simulation and control of an evaporator: Modèle général dynamique pour évaporateurs et condenseurs frigorifiques. Partie II: Simulation et régulation d'un évaporateur

A mathematical model of an evaporator based on one-dimensional partial differential equations representing mass conservation, and tube wall energy has been formulated. These equations are then restructured and linked to a program data base of all major refrigerants and refrigerant mixtures. The result is a simulation model of an evaporator that is general and flexible. The model is tested over a wide range of operating conditions and a simple controller is implemented to demonstrate the effectiveness of the model for controller and systems design.     

HYDRODYNAMICS AND HEAT TRANSFER AT THE BOILING OF LIQUIDS IN THIN-LAYER EVAPORATOR WITH VIBRATING ELEMENT

This paper extends and broadens our present knowledge concerning hydro-dyanmics and heat transfer during boiling of liquids in a thin-layer evaporator equipped with a spiral element. The application of the spiral element in the thin-layer evaporator of static type (STLE) radically changes the hydrodynamics and consequently the rate of heat transfer. Measurements were carried out on distilled water and ethylene glycol. 416 measurements of individual heat transfer coefficients (IHTC) were performed which included 86 measurements in the STLE, 77 measurements in the thin-layer evaporator equipped with immovable spiral element (TLE) with (ISE), and 253 measurements in the thin-layer evaporator with movable spiral element (TLE) with (MSE). Experimental data were correlated using similarity theory and dimensional analysis. The experimental results obtained in the TLE with MSE were compared with adequate data obtained in the TLE with ISE. In the investigated range of frequency and amplitude the increase of IHTC amounted to 10·1% for distilled water and for ethylene glycol 30·7%.     

Thermal design method of bayonet-tube evaporators and condensers

The paper describes an effectiveness-NTU design method of bayonet-tube evaporators and condensers. Including the effect of the wall superheat on the shell-side film coefficient, and using an energy balance on the tube, differential equations for the steady-state fluid temperatures are formulated. Because of the nonlinear nature of the governing equations, the fourth-order Runge-Kutta method is employed to the solution of the finite difference equations. The results are iterated with the combination of integration techniques. An upper bound to the numerical error being ±5% the fluid temperature distribution as well as the exchanger effectiveness are determined, and presented as a function of the Hurd number, the number of heat transfer units and the flow arrangement. For flow entering through the inner tube, the temperature distribution displays the occurrence of a minimum at a point other than the tube-tip of the exchanger. In an extension of the analysis, an effort is made to illustrate the deviation of the results obtained by uniform film coefficient from the present study, and the differences are outlined.     

分析型全蒸发器在啤酒挥发性成分测定中的应用

综述了分型全蒸发器技术在啤酒发酵过程中的应用状况，并介绍了分析型全蒸发器模型结构及与之配合使用的连续多分支管。     

板式升膜蒸发器在离子膜烧碱中的应用

介绍了升膜蒸发的原理及影响传热量的因素。重点介绍了板式升膜蒸发器在离子膜烧碱蒸发系统中的应用情况及蒸发装置的特点。     

Ⅰ效蒸发器液位控制改造

叙述了Ⅰ效蒸发器液位测量所存在的问题并提出了解决方案，新改进的液位测量控制合理、简单、便于维护，投运效果良好。     

低成本连续化的氯化锌制造工艺

以锌灰和废盐酸为原料，用连续反应装置生产氯化锌，不仅成本低，而且无气体逸出；用蒸发器代替敞开式的石墨板蒸发器，不仅节省能量，而且无蒸汽四逸；采用可回收滤渣的工艺，既回收了有利用价值的铅、铜、三氧化二铁等物质，又解决了重金属的污染问题。经厂家的生产实践证明，这种氯化锌制造工艺既避免了污染，又能获得较好的经济效益。     

板翅式蒸发器液冷系统设计

为了研究板翅式换热器在沸腾相变换热情况下的传热及压降特性,设计一套采用氟里昂蒸气压缩循环的液体冷却试验系统,其中板翅式换热器作为蒸发器,R22作为制冷剂,热水作为被冷却液体提供制冷剂蒸发所需热量。对该系统的运行工况、参数范围及系统各部件（包括压缩机、冷凝器、毛细管、板翅式蒸发器）进行设计及选择,并介绍所搭建的试验台。     

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。