螺杆制冷压缩机特性研究及新机型开发

针对螺杆制冷压缩机的特性进行了系统深入的研究,测录了压缩机的P-V图,研究了不同的压缩机冷却方式,比较了闪蒸式和换热器式经济器循环特性,还测试了R22、R134a、R404A、R407C等不同工质的性能.在此基础上,利用升级后的SCCAD螺杆压缩机设计计算软件,开发了专用的转子新型线,研制成功了多种型号的新一代开启式和半封闭式螺杆制冷压缩机.     

螺杆冷水机组与螺杆制冷压缩机组通过鉴定

由武汉制冷设备总厂承担的一机部新产品JZ—KF125C螺杆冷水机组和省新产品KF125C螺杆制冷压缩机组鉴定会于今年5月19日至21日在武汉召开。会议由一机部委托武汉市机械局主持。一机部通用总局和有关主管部门、企业、设计部门和高等院校等54个单位70名代表参加了会议。 KF125C螺杆制冷机转子型线采用单边非对称摆线,圆弧型线,使用R22工质,标准工况下设计制冷量11369大卡/时,实测115947大卡/时,设计轴功率39.82千瓦,实测40.8千瓦,机组噪音值85分贝左右。     

风冷螺杆式制冷机组性能优化的试验研究

介绍了风冷螺杆制冷机组在部分负荷条件下综合部分负荷性能系数(IPLV)的试验研究情况,结果表明,在AHRI标准和GB标准2种测试工况下,采用变频技术和可变内容积比控制的制冷机组IPLV比普通制冷机组的有明显提高,采用变频技术时的IPLV比采用可变内容积比时提高更多,并且随着负荷的降低,IPLV变化越明显。另外AHRI标准下IPLV比GB标准下更高。     

R134a、R417a和R22用于空气源热泵热水器的性能研究

在焓差法空调器性能测试平台上,对空气源热泵热水器分别用R134 a、R417 a和R22进行各种典型工况下的试验,对3种制冷工质的吸排气压力、吸排气温度、压缩机输入功率、制热量、性能系数进行对比分析,分析验证了各参数随环境工况变化的关系,得出了在不同工况下的各特性参数的变化规律,为热泵热水器的设计及工质选用提供了参考。     

R22的替代物THR03的实验研究及性能分析

在一新建的高精度实验台上分别对以R22及THR03为制冷工质的制冷系统在4个工况下进行了系统的实验研究,由实验得到了THR03、R22在4种工况下制冷系统制冷量、压缩机耗功量、压缩机排气温度等性能参数实验数据,分析和比较了THR03制冷系统及R22制冷系统在同一工况下的性能,并给出了实验结果.     

非共沸混合工质用于螺杆膨胀机双循环低温余热回收系统的理论研究

以典型干工质R245fa和典型湿工质R152a为组元的按不同质量比例组成的M1、M2和M3这三种典型的非共沸混合工质,在设定工况下对其应用于螺杆膨胀机双循环低温余热回收系统性能进行理论研究。针对非共沸混合工质相变时发生温度滑移以及螺杆膨胀机压降小,出口参数高的特性,系统中引入内部回热器。分析结果表明,使用混合工质可拓宽螺杆膨胀机双循环系统的工质选择范围并且混合工质换热过程与变温热源能很好的匹配,从而可以减少传热温差带来的不可逆损失,同时使用混合工质可降低系统工质质量流量;非共沸混合等墒工质在设定工况下循环效率不是最高,但膨胀比最小,可减少膨胀机体积,降低设备制造成本;非共沸混合工质应用于螺杆膨胀机双循环系统时,引入内部回热器能够使循环效率得到明显提高。     

大功率制冷压缩机性能测试新装置

介绍了一种采用液体流量计法测试制冷压缩机性能的新装置.它具有测试精度高、投资省、运行费用低的特点.同时该系统装置也更易于保证使用非共沸工质时被测压缩机的吸气成分,适用于R410A、R407C等新制冷工质.     

闪发蒸汽冷却技术及R134a用于高温空调器的研究

建立了基于闪发蒸汽冷却技术及R134a为工质的高温空调器数学模型,分析并比较了R22单级压缩、R22闪发蒸汽冷却和R134a单级压缩制冷系统在不同室外气温度下系统冷凝压力、压缩机排气温度、制冷量、耗功和性能系数。结果表明,相同工况下R134a制冷系统的冷凝压力和排气温度最低,制冷量较小,较R22制冷系统适宜于环境温度50℃以上工况。当环境温度介于42~50℃时,闪发蒸汽冷却技术可有效降低以R22为工质的空调压缩机的排气温度,提高系统制冷量和性能系数,但冷凝压力和耗功略有升高。     

小型滚动转子压缩机使用R502和R22的性能对比

对同一台小型滚动转子压缩机,分别使用R502和R22进行变工况下的整体热力性能试验,通过对比二者的性能参数,表明使用R502可使制冷量和容积效率有所提高,排温有所下降,提高了压缩机的可靠性,延长了制冷机的寿命,并且在蒸发温度较低、冷凝温度较高的场合,采用R502具有较明显的节能效果。此外,实验还表明,制冷系数与压力比有一对应关系,并拟合出了该关系式。     

螺杆制冷机经济器系统的设计

螺杆制冷机的特点之一是单级压比大,随着压比的增大机器的功耗增加、冷量减小、效率下降。为了改善机器性能,可利用螺杆压缩机吸气、压缩、排气单向进行的特点,在压缩过程的中途,设置一个补气口,使单级螺杆压缩机按两级制冷循环运转,即经济器系统。本文阐述了经济器系统的设计计算方法,以及补气口的位置、大小与布置等问题。并以R717(氨),R22为工质分别作了热力计算,计算结果同已有试验结果很接近。     

双螺杆制冷压缩机工作过程的数值模拟

双螺杆制冷压缩机由于其独特的优势已被广泛应用,但由于其复杂的转子结构及型线设计,对该类压缩机的整体性能的预测一般采用一维数值模拟或经验方式得到,但是该类方法无法获得压缩机内部流体压力场和温度场的分布情况。根据试验用螺杆压缩机建立了三维模型,利用结构化动网格技术,通过CFD软件对双螺杆压缩机的内部流场进行了三维数值模拟,分析了流体在压缩机内部的流动及热力学参数分布状况,得到了压缩机内部压力场、温度场和速度场的分布规律。将三维数值模拟得到的P-V指示图及压缩机宏观性能参数与试验结果进行对比分析,发现模拟结果与试验数据基本一致,部分负荷时误差较大,误差最大的是绝热效率,为2.58%。数值模拟能够准确预测双螺杆压缩机的性能,并为压缩机设计提供了新的方法。     

Exergy efficiency and irreversibility comparison of R22, R134a, R290 and R407C to replace R22 in an air conditioning system

This work presents an experimental comparison of exergy efficiency (EE), irreversibility at the process 1–2 (evaporator exit to compressor inlet), 2–3 (compressor inlet to condenser inlet), 3–4 (condenser inlet to expansion valve inlet), 4–5 (expansion valve inlet to evaporator inlet) and 5–1 (evaporator), and coefficient of performance (COP) of R22, and its substitutes R134a, R290 and R407C in vapor compression refrigeration system (VCRS) of an air conditioner. In addition, the effects of air temperature in the freezer with reference to environment states on irreversibility and EE have been investigated. At ?18°C air temperature in the freezer, 33°C reference environment state and 42% relative humidity refrigerants R22 and its substitutes R134a, R290 and R407C VCRSs the total irreversibilities are 665.7, 753.5, 582.1 and 677 W, and EEs are 22.9, 14.2, 26.5 and 20.6%, respectively. The refrigerant R290 is the best performer among candidate refrigerants but it suffers from flammability. Thus, R407C can considerably be used to replace R22.     

近共沸混合制冷剂R410A的研究进展

介绍了目前国内外对制冷空调系统替代制冷剂的有关研究，制冷剂R22的替代物R410A的安全环保性、热力学性能、蒸发冷凝换热特性、在节流元件中的性能以及对现用压缩机及润滑油的适应性等方面的研究现状。该工作对新工质R410A如何更好地适应现有的制冷空调系统很有意义。     

Lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems (the influence of alternative refrigerants)

The rolling piston type rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed characteristics. However, it is necessary to develop alternative refrigerants that can guarantee environmental protection. In addition, advanced refrigerant compressors must be further developed to overcome the compatibility problems inherent in refrigeration and air-conditioning systems. The refrigerant compressor is the most important mechanical component, which determines the performances of refrigeration and air-conditioning systems. Therefore, we theoretically investigated the lubrication characteristics of the rotary compressor currently used in both refrigeration and air-conditioning systems with an alternative refrigerant. In the theoretical investigation, the Runge-Kutta method is used to analyze the behavior of a rolling piston in the rotary compressor. Subsequently, the Newton-Raphson method is used, which provided good performance in the analysis of the elastohydrodynamic lubrication of the line contacts between a rolling piston and a vane in the rotary compressor. The results demonstrate that the alternative refrigerants influence the friction force and the energy loss between the vane and the rolling piston.     

R290制冷空调系统的现状与未来发展

详细分析和总结了国内外自然工质R290制冷空调系统的应用与研究现状。R290单位容积制冷量大、价格低廉、臭氧消耗潜值为0,全球变暖潜值很小,热力性能与常规制冷剂相比有明显的优势。R290制冷空调系统结构紧凑,制冷剂的充灌量少,金属材料的消耗少,设备的初投资少。随着R290应用技术研究的不断深入,环保制冷剂R290将拥有广阔的市场应用前景,在未来制冷空调系统中将显示出巨大的优越性。     

培尔顿式膨胀-辅助压缩机在制冷系统中的研究

研究了一种具有简单结构的培尔顿式膨胀-辅压一体的能量回收装置,可用于小型制冷系统中取代节流阀,回收膨胀过程的压力损失,并将其直接转化为机械功作用于系统中,达到能量回收利用的目的.通过理论分析和模拟计算,比较了辅助压缩机在系统中的布置方式对回收功、制热量、COP等参数的影响,并对常用氟利昂工质R410A、R134a、R22的运行参数进行了比较.设计并制作了能量回收装置的样机,搭建了可供系统试验比较的测试台,讨论了部分试验结果及改进方向.     

双螺杆制冷压缩机转子轴心轨迹波动特性试验研究

随着制冷系统的不断发展,双螺杆制冷压缩机作为系统的核心部件,其运行压力也越来越高,使得滑动轴承的应用也越来越广泛,以承受不断增大的转子径向力,而转子轴心轨迹是滑动轴承工作状态的综合反映。本文通过搭建双螺杆制冷压缩机转子轴心轨迹测试系统,对不同工况以及内容积比下的轴心轨迹进行了试验研究。研究结果表明:与滚动转子压缩机、离心压缩机等旋转机械不同,双螺杆压缩机的转子轴心轨迹大致呈椭圆形,且每个运行周期中还存在若干波动,这些波动的数目对应于压缩机的阴转子齿数,即转子径向动载荷的波动频率。     

Friction and Wear Characteristics of TiN Coated Vane for the Rotary Compressor in a R410A Refrigerant©

HFC is a potential alternative refrigerant for CFC, which depletes the ozone layer. The rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed operation. R410A, an HFC refrigerant, is used in a refrigerator compressor, but its frictional characteristic is not established. In this study, the influence of R410A refrigerant on the roller-vane surfaces was studied, and friction and wear characteristics of the TiN coated vane were investigated. The friction and wear data were obtained with a specially designed high-pressure wear tester. A testing environment charged with HFC refrigerant more closely simulates the operating conditions of a real rotary compressor. In pure oil without R410A, wear of the TiN coated vane was larger than that of the uncoated vane. But when the refrigerant was dissolved in oil, wear of the uncoated vane was larger than that of the TiN coated vane. This showed that a TiN coated vane is good relative to wear resistance in the refrigerant/lubricant mixed environment. As the rotating speed of the frictional motion increased, wear increased. But in the high-velocity region, wear decreased because the boundary lubrication is changed into the mixed lubrication in the lubrication region. As the pressure grew larger, wear volume and coefficient of friction became larger. This is because the amount of the refrigerants dissolved in oil increased and the viscosity of oil dropped as the pressure increased.     

R410a和R22平行流冷凝器变工况特性的比较

对比研究了分别采用R22及其替代工质R410a的平行流冷凝器在室外变工况下性能的同异。通过建立平行流冷凝器的稳态分布参数模型,仿真研究了不同冷凝温度下R410a和R22的变工况特性,并引入质能比的概念对这两种工质的单位换热量所需制冷剂质量的多少进行了比较。仿真结果是R410a和R22的换热量、制冷剂侧压降和制冷剂质量随工况和冷凝温度的改变具有的相似的变化趋势,且R410a具有较高的换热量和较低的压降;两者的质能比随进风温度和进风量的升高均呈基本一致的向上抛物线的变化趋势,且R410的质能比低于R22。可以得出R410a与R22具有相似的变工况特性,适合替代R22应用于采用平行流冷凝器的汽车空调。并且R410a在传热、流动性能和降低制冷剂充注量方面均优于R22。