外文翻譯---潤滑油在制冷中的效用

1、外文資料譯文：The The effect effect of of oil oil in in refrigeration: refrigeration: Current Current research research issues issues and and critical critical review review of of thermodynamic thermodynamic aspects aspectsMoha

2、mmed Youbi-Idrissia,1, Jocelyn Bonjourb,aCemagref, Refrigerating Processes Research Unit, Parc de Tourvoie, BP 44, 92163 Antony Cedex, FrancebCETHIL – UMR5008 CNRS INSA-Lyon Univ. Lyon1, Ba? t. Sadi Carnot, 9 rue de la

3、Physique, INSA-Lyon,F-69621 Villeurbanne Cedex, FrancA lubrication agent is necessary in almost all the refrigeration vapour compression systems,particularly for the correct operation of the compressor. However, a certai

4、n portion of the oilalways circulates with the refrigerant through the cycle. This circulation is at the origin ofa deviation from the theoretical behaviour (i.e. based on pure refrigerant) of the components.This articl

5、e aims at reviewing the oil-related researches in the field of refrigeration. Previousreviews in the literature focused on the thermo-hydraulic consequences of the presence of oil; we will analyse here its thermodynamic

6、al consequences. In a first part, a brief literature review will give an overview of current scientific and technological issues concerning the impact of oil on components or on whole refrigeration systems. The typical

7、approaches and methods employed to address this problem will be described. These researches require sound tools for the evaluation of thermodynamic properties of refrigerant–oil mixtures.The second part of this article

8、is hence a critical review of these tools, and focuses particularly on liquid–vapour equilibrium, absorption–diffusion, and mixture enthalpy calculation. a 2007 Elsevier Ltd and IIR. All rights reserved. 1. Introduction

9、 In the refrigeration and air-conditioning vapour compression systems, oil is necessary for a correct working of the compressor.Its main role is indeed to ensure the existence of a thin oil film allowing the lubrication

10、 of the mechanical movingelements (pistons, connecting rod/crank, valves, .), i.e. toprotect them against wear. The lubricant simultaneously ensures several secondary roles among which serving as a tightness element, li

11、miting the noise, or helping the evacuationof chemical impurities or deposits that may be present in the system. Lastly, in many situations, the oil is also used as a heat transfer medium for cooling the compressor. All

12、 these favourable actions of oil show that oil is definitely useful in refrigeration units. However, the presence of a lubricant is also accompanied by several drawbacks, among which the most often cited is a reduction

13、 in heat transfer coefficients in the two-phase heat exchangers (condenser and evaporator).The presence of oil also systems. Its goal is to give an overview of current technological or scientific issues through a brief

14、analysis of a choice of some typical recent publications. This will show that these research works require sound tools for the evaluation of thermodynamic properties of refrigerant–oilmixtures. Section 3 consists in a

15、critical reviewof these tools,and focuses particularly on liquid–vapour equilibrium, dynamic effects (absorption–diffusion), andmixture enthalpy calculation.2. Thermodynamical analysis of the impact of oil in refrigerat

16、ion As exposed in Section 1, we will not discuss here the effect of oil on heat transfer in the heat exchangers or on the pressure drops, but only the thermodynamic effects. The presence of oil influences the behaviour

17、 of almost each component of refrigeration units. It is, however, usually admitted that the condenser is the least sensitive component to the presence of a lubricant, and the literature is consequently scarce on that su

18、bject, while the compressor, the evaporator and the pipes or capillary are the subject of a larger number of publications, some of which are analysed in the next sections.2.1. Impact on components2.1.1. CompressorA majo

19、r effect of the presence of a lubricant in the compressor is the foaming phenomenon: the foam is due to the oil– refrigerant interaction because of the blade rotation and/or the vapour blow. For instance, Yanagisawa et

20、al. (1991) experimentally investigated the foaming occurring in a hermetic casing that simulates a hermetic rotary compressor. They noticed that the foaming becomes violent at high compressor blade speed and at high flow

21、 rate of the blowing vapour, but that these both effects are not necessarily cumulative. The foaming is relatively violent when the pressure is close to the saturation pressure corresponding to the temperature in the cas

22、ing. Some other information such as the foam lifetime, effects of the oil mixing ratio, of the viscosity, etc., were also investigated. Another concern with oil is the question of its circulationrate (OCR, Oil Circulatio

23、n Ratio), or conversely its return to the compressor. The OCR seems to be relatively independent of the operating conditions, at least for R-290/POE oil orR-407C/POE oil, but the OCR seems to be slightly higher with POE

24、 oils than with mineral oils (Navarro et al., 1998, 2004,2005). The oil return can be analysed in terms of presumed benefits of a high miscibility vs. actual lubrication properties of the refrigerant–oil mixtures (whic

25、h are poorer than those of pure oil properties, since a portion of liquid refrigerant can be dissolved in the oil) and overall energy efficiency.Reyes-Gavilan et al. (1996a,b) showed that a well-chosen non-miscible oil

26、 can perform as well as a POE miscible oil in a R-134a household refrigerator, i.e. both yield about the same energy efficiency with about the same amount of oil trapped along the circuit. In some other works, the quest

27、ion of oil return is linked to specific configurations, such as a pair of compressors working in parallel: Winandy and Cuevas (2003) monitored and analysed the oil level of two compressors linked with line allowing for