涡旋压缩机的并联使用

结合并联涡旋压缩机组的结构特点，介绍涡旋压缩机并联使用的优点，着重分析其使用过程中的回油问题，并根据试验结果客观分析比较目前市场中两种并联结构一高压内部供油机组和低压均油均气机组的优缺点。     

Modelling of reciprocating and scroll compressors

This paper presents simple and thermodynamically realistic models of two types of compressors widely used in domestic heat pumps (reciprocating and scroll compressors). These models calculate the mass flow rate of refrigerant and the power consumption from the knowledge of operating conditions and parameters. Some of these parameters may be found in the technical datasheets of compressors whereas others are determined in such a way that the calculated mass flow rate and electrical power match those given in these datasheets.The two models have been tested on five reciprocating compressors and five scroll compressors. This study has been limited to compressors with a maximum electrical power of 10 kW and for the following operating conditions: evaporating temperatures ranging from −20 to 15 °C and condensing temperatures ranging from 15 to 60 °C.The average discrepancies on mass flow rate and power for reciprocating compressors are 1.10 and 1.69% (for different refrigerants: R134a, R404A, R22, R12 and R407C). For scroll compressors, the average discrepancies on mass flow rate and power are 2.42 and 1.04% (for different refrigerants: R134a, R404A, R407C and R22).     

The effect of scroll wraps on the performance of scroll compressors

A number of geometrical curves have been used to form the wraps of scroll compressors. When the suction pressure, pressure ratio, scroll wrap height and thickness, and suction volume are constant, the effect of the involute curves of a cricle, square and line segment on the performances of the scroll compressor, such as geometrical parameters, leakage line length and various gas forces acting on the orbiting scroll are analysed in this paper. The effects of these scroll wraps on the performance of the scroll compressor vary as the suction volume changes. The results in this paper should be considered in scroll compressor design.     

并联涡旋式压缩机在空气源热泵机组中的应用分析

结合并联涡旋式压缩机的结构特点,介绍涡旋式压缩机并联使用的技术优势;对空气源并联涡旋式热泵机组进行试验研究,并与同冷量的空气源螺杆式热泵机组进行对比。试验发现,空气源并联涡旋式热泵机组具有更高的能效比。最后,给出并联机油气平衡问题的解决措施。     

涡旋压缩机在热泵热水器中的应用

热泵热水器以制取热水为目的，有别于普通制冷或空调设备。热泵热水器运行时冷凝温度和冷凝压力很高，对压缩机的可靠性和应用技巧提出了较高要求。涡旋压缩机以其可靠性好、效率高，在热泵热水器中得到了大量应用。     

New non-dimensional performance parameters for the characterization of refrigeration compressors

Pierre (1982) developed general correlations of compressor performance for a wide range of open piston compressors based on a vast amount of data provided by the most important open compressors manufacturers at that time. Based on a wide experimental test campaign with 6 different hermetic and semihermetic compressors, this paper assesses the potential of Pierre's correlations to describe the performance of modern compressors. A full review of the functionals proposed by Pierre in order to improve their accuracy was then performed and as a result the authors found that it is possible to improve the characterization by employing a nondimensional definition of the compressor performance instead of using the efficiencies. These new parameters provide a much more consistent estimation at the borders of the correlation range than the usual correlation obtained following the ARI standard, and could be even employed to extrapolate the performance of the compressor to non-tested conditions with reasonable accuracy.     

涡旋并联机与螺杆压缩机的效率和成本分析

从效率与成本的角度对涡旋并联机和螺杆压缩机进行比较分析。     

Scroll profiles in scroll compressors: General criteria and error sensitivity

General criteria for scroll profiles that include the evolute, orbiting movement, differential, and integrative conditions are proposed. The profile error sensitivity is defined based on the composite meshing error and meshing clearances of the scroll profiles. A case study on regular polygon involutes as scroll profiles indicates that the general criteria are satisfied when the edge number of the two involutes of a regular polygon is equal to the common multiple of the doubled number of scroll wraps on one scroll. The profile error sensitivity of the involutes of a base circle is shown to be controlled by the radial machining error, which is extremely low. The involute of a base circle is the ideal profile for a scroll compressor because it contains low error sensitivity and more stable dynamic characteristics.     

并联涡旋式压缩机油平衡特性的试验研究

分析并联压缩机的油平衡特性,比较几种油平衡方式,并对非平衡式的涡旋式压缩机并联机组进行油平衡试验,试验结果表明,采用丹佛斯专利技术一油气分配管,能够解决机组的油平衡问题。     

行业标准JB/T《高温热泵用全封闭涡旋式制冷剂压缩机》要点解读

高温热泵技术可实现在工商业诸多领域的推广应用,其核心设备压缩机产品的标准化意义重大。本文阐述已完成报批的行业标准JB/T《高温热泵用全封闭涡旋式制冷剂压缩机》的编制背景,从标准名称、适用范围、基本参数、名义工况与性能允差、其他综合性能评价项目等方面解读该标准的技术要点。     

A general geometrical model of scroll compressors based on discretional initial angles of involute

Based on discretional initial angles of involute of scroll compressors, a general mathematical representation of scroll wraps, working chamber volume and leakage areas is presented. The scroll wraps' geometrical expressions, including interaction arc, of the involute angle with discretional initial angles of involute are developed. By using it, a new calculation formula of working chamber volume without restriction to special involute initial angles is set up and the expression of the volume during all the suction, compression and discharge processes in a general subsection function style is given. A geometrical model of leakage areas, including flank in, flank out, radial in and radial out, is also developed based on the discretional initial angles condition. Finally, this geometrical model is applied in a thermodynamic model and the simulation results are compared with some former experimental results. It is found that this model has a satisfactory accuracy and is easy to be used in thermodynamic simulation.     

Detailed thermodynamic characterization of hermetic reciprocating compressors

The aim of this paper is the detailed analysis of different well-known thermodynamic efficiencies usually used to characterize hermetic compressors. Attention is focussed on the volumetric efficiency, the isentropic efficiency, and the combined mechanical–electrical efficiency. A procedure is presented to detach these efficiencies into their main components (physical sub-processes) to get deeper insight on the overall behavior.The volumetric efficiency is split into partial efficiencies related to pressure drop and heat transfer effects, supercharging effects, superdischarging effects, leakages, etc. The isentropic efficiency is detached using two different points of view: the work associated to the individual sub-processes (compression, discharge, expansion, suction), and the work associated to the underpressures, overpressures, and between the inlet and outlet mean compressor pressures. Finally, the combined mechanical–electrical efficiency is related to the heat transfer losses/gains, and to the exergy transfers and exergy destroyed.Even though some of the concepts introduced in the paper can be applied to different kinds of compressors, the discussion is specially focussed on hermetic reciprocating compressors. An advanced simulation model developed by the authors has been used to generate data to illustrate the possibilities of the detailed thermodynamic characterization proposed. The criteria developed are useful tools for comparison purposes, to characterize compressors, and to assist designers during the optimization process.     

螺杆式压缩机无级调节负荷判断的新方法

通过对压缩机厂家测试数据进行分析、计算,拟合负荷判断方程,最终给出压缩机无级调节负荷判断的控制逻辑,并且通过实例验证此逻辑的正确性。     

New seeding methodology for gas concentration measurements

This paper presents the first demonstration of the pulsed laser ablation technique to seed a laminar non-reacting gaseous jet at atmospheric pressure. The focused, second harmonic from a pulsed Nd : YAG laser is used to ablate a neutral indium rod at atmospheric pressure and temperature. The ablation products generated with the new seeding method are used to seed the jet, as a marker of the scalar field. The neutral indium atoms so generated are found to be stable and survive a convection time of the order of tens of seconds before entering the interrogation region. The measurements of planar laser-induced fluorescence (PLIF) with indium and laser nephelometry measurements with the ablation products are both reported. The resulting average and root mean square (RMS) of the measurements are found to agree reasonably well although some differences are found. The results show that the pulsed laser ablation method has potential to provide scalar measurement for mixing studies.     

Test methodology for the thermal shock characterization of ceramics

An experimental methodology is proposed to evaluate the thermal shock resistance of ceramics. A technique based on infrared heating has been developed to perform systematic and well controlled thermal shock experiments. This novel technique was used to evaluate the resistance of yttria-stabilized zirconia–alumina foams to thermal loads. Foams of varying cell sizes were subjected to thermal shock and the damage was evaluated using retained strength and non-destructive elastic modulus measurements. The transient thermal gradients and the resulting thermoelastic stresses in the foams were predicted using finite element analysis and the extent of damage was correlated to the maximum thermal strains generated in foams.     

涡旋式压缩机中间补气技术

对带有中间补气功能的涡旋式压缩机理论循环进行分析,针对在不同蒸发温度下采用中间补气对涡旋式压缩机的能力、功率、排气温度及能效比的影响进行试验研究与分析。结果显示,与普通涡旋式压缩机相比,带有中间补气功能的压缩机在蒸发温度由-5℃到-20℃之间变化时,其能力提升约15%～30%,能效比提升约9%～19%,功耗仅上升约10%。