动磁式直线压缩机的电磁力及其等效电路模型

推导了动磁式直线压缩机中电磁力的表达式,并利用简化分析式和有限元分析方法模拟分析了直线电机主要结构参数对电磁力的影响。研究表明,电磁力随直线电机气隙高度的增大而减小,随环状永磁体的半径和厚度的增大而增大。分析式和有限元模拟结果具有合理的一致性。同时,建立了动磁式直线压缩机的等效电路模型,推导了获得压缩机整机最大能量转换效率的表达式及各个参数对该转换效率的影响,并得到了最大能量转换效率下的活塞面积。     

冰箱直线压缩机不稳定波动的机理分析

直线压缩机冰箱制冷系统的实验研究显示,在初始启动调节后供电参数保持不变过程中,直线压缩机出现了不稳定波动现象。最大的行程波动率约为3.8%,输入功的波动率约为21.3%,波动周期约为220 s。通过建立的直线压缩机动态仿真模型,对该不稳定现象进行解耦分析,结果表明：吸气压力的波动对直线压缩机行程的影响较大,排气压力的波动对其影响很小,但行程的波动对排气压力有一定的影响。直线压缩机启动过程中行程的反复调节引起了排气压力出现较大的波动,经过一段稳定运行后,该波动传递到直线压缩机的吸气端,从而引起了所述的不稳定波动。     

降低吸气温度的高效冰箱压缩机

当今世界上对家用电冰箱和冷藏箱的压缩机追求的两项主要目标,一是高效率(即低能耗);二是低噪音。本论文讨论了改进往复式压缩机的吸气消音系统的方法,使吸气温度降低,从而提高压缩机效率和降低噪音。由于压缩机是密封在壳体内,要将压缩机壳外的低压侧的气体引进气缸中,而同时又不使进气温度有很明显的提高是非常困难的。此外,当我们在考虑用隔离吸气热传导的方     

冰箱用HFC134a旋转式压缩机的进气管绝热设计方法

分析了进气管的绝热改进是传统的冰箱用旋转式压缩机使用ＨＦＣ１３４ａ制冷剂时提高性能的一种有效方法；建立了进气管绝热设计的传热模型；介绍了旋转式压缩机使用新制冷剂ＨＦＣ１３４ａ后进气管的绝热设计方法和算例。     

冰箱直线压缩机运行不稳定的实验研究

本文进行了直线压缩机冰箱系统的制冷实验,分析了直线压缩机运行的不稳定特性。结果表明:冰箱制冷过程中直线压缩机定频运行,会出现三种不同的不稳定状态:启动调节不稳定、外部扰动不稳定和电磁阀调节不稳定。启动过程中,供电参数的调节以及吸排气压力的变化引起的不稳定状态,随着电参数保持不变和吸排气压力趋于稳定,启动过程的不稳定现象也逐渐消失。当供电参数和制冷工况保持稳定时,制冷系统的随机扰动也会使直线压缩机产生一定的不稳定振荡,行程最大振幅约0.3 mm,电流和输入功的最大波动约为平均值的10%,直线压缩机对外部扰动具有自修复性。电磁阀调节过程对直线压缩机的稳定性影响较大,行程最大振幅约2.2 mm,压缩机存在极大的撞缸可能性。因此非常有必要结合制冷系统的运行工况,进行直线压缩机本体结构和控制系统的优化设计,保证直线压缩机在冰箱调节过程中安全可靠的运行。     

CFC12工质替代后冰箱压缩机气阀的重新设计

以ＱＤ６７Ａ型冰箱压缩机为研究对象，从理论上分析和预测了以ＨＦＣ１５２ａ／ＨＣＦＣ２２混合工质替代ＣＦＣ１２后压缩机气阀的性能，并进行了使气阀适应替代工特征的重新设计和实验研究。研究结果表明，使用替代工质后，改进后压缩机的性能系数和制冷能力双改进前分别高出１０．３％和２１．７％。     

冰箱压缩机壳体的隔声效果研究

本文介绍了冰箱压缩机壳体的隔声试验及动态测量，研究了两种不同钢材和厚度壳体的隔声效果，以及在机械性能，动态特性等方面的比较，并从壳体的模态试验中验证了壳体的固有频率。压缩机的噪声，主要是通过机壳辐射出去的，要提供一个结构合理，辐射噪声尽量小的壳体，应从选择合适材料和壳体的厚度提高壳体的刚度及阻尼，改进壳体的外形设计等方法考虑，这是改善压缩机噪声的有效途径。     

Effect of pulse tube volume on dynamics of linear compressor and cooling performance in Stirling-type pulse tube refrigerator

In a Stirling-type pulse tube refrigerator (PTR), the pulse tube volume affects the dynamic behavior of a linear compressor as well as the cooling performance of PTR. In this study, PTRs which have different pulse tube volume are tested and simulated. The simulation code is verified with the experimental measurement of piston displacement, pressure wave, input power and cooling capacity. And then, the power transfer from the electric power input to the cooling capacity is explained with the simulation results. The smaller pulse tube increases the resonant frequency of a linear compressor and suppresses the piston motion because it imposes larger gas spring effect and also larger gas damping effect to the piston. The smaller one allows larger power transfer from electric power to expansion PV work despite the smaller piston displacement, but shows less cooling capacity due to larger thermal losses.     

Split-type free-displacer Stirling refrigerator design using linear network analysis

A linear network analysis is developed for the system design of split-type free-displacer Stirling refrigerators. The dynamics models are derived to describe the input/output relation of each component by use of the governing equations in conjunction with linearization and approximation. By connecting the equivalent circuits of the components together, a linear network consisting of a fluid network and a displacer network is obtained. The fluid network accounts for the propagation of gas flow induced by the pressure wave; while the displacer network accounts for the displacer motion induced by the pressure force exerted on the displacer. Two transfer functions are further derived for the displacer motion and the gas pressure of the expansion space with respect to the piston motion. The system performance is then evaluated from the frequency response of the transfer functions by using the sinusoidal signal analysis. The performance prediction of a split-type free-displacer Stirling refrigerator using the linear network analysis is shown to be satisfactory.     

电冰箱压缩机吸气消声器流动与声学性能分析

分别对电冰箱压缩机半直接吸气消声器和直接吸气消声器的流场和声场进行数值模拟,对其流动特性和声学性能进行对比分析。研究成果可用于预测电冰箱压缩机消声器的综合性能,为消声器的设计、选型及结构优化提供理论依据。     

润滑油对R134a冰箱压缩机性能影响的研究

研究了润滑油对Ｒ１３４ａ旋转式冰箱压缩机性能的影响。对比试验表明，国产牌号的润滑油能够满足工质替代对润滑油特性的要求，润滑油不同。工作替代的效果便有差异。     

压缩机选型对电冰箱实际使用性能的影响

通过分析压缩机制冷量对电冰箱运行的影响,阐述小冷量压缩机匹配电冰箱时在耗电量、最大热负荷等方面的优劣势。指出采用小冷量压缩机匹配大电冰箱时,必须在降低能耗的同时关注电冰箱在最大热负荷下储藏温度、压缩机工作系数等。     

Stirling-type pulse tube refrigerator (PTR) with cold compression: Cold compressor,colder expander

This research paper focuses on the performance prediction and its validation via experimental investigation of a Stirling-type pulse tube refrigerator (PTR) equipped with a cold linear compressor. When the working gas is compressed at cryogenic temperature, the acoustic power (PV power) can be directly transmitted through the regenerator to the pulsating tube without experiencing unnecessary precooling process. The required PV power generated by the linear compressor, furthermore, can be significantly diminished due to the relatively small specific volume of the working gas at low temperature. The PTR can reach lower temperature efficiently with higher heat lift at the corresponding temperature than other typical single-stage Stirling-type PTRs. Utilizing a cryogenic reservoir as a warm end and regulating the entire operating temperature range of the PTR will enable a PTR to operate efficiently under space environment.In this research, the experimental validation as a proof of concept was carried out to demonstrate the capability of PTR operating between 80 K and 40 K. The linear compressor was submerged in a liquid nitrogen bath and the lowest temperature was measured as 38.5 K. The test results were analyzed to identify loss mechanisms with the simple numerical computation (linear model) which considers the dynamic characteristics of the cold linear compressor with thermo-hydraulic governing equations for each of sub components of the PTR. All the mass flows and pressure waves were assumed to be sinusoidal.     

Analysis on the stirling-type pulse tube refrigerator in consideration of dynamics of linear compressor

This paper describes the performance analysis of Stirling-type pulse tube refrigerator (PTR) in conjunction with the dynamics of the accompanied linear compressor. The dynamic behavior of the piston in the linear compressor is directly influenced by the load condition of the PTR. In this paper, the dynamic equation of the piston is simultaneously solved with the thermo-hydraulic governing equations of the PTR using linear analysis model and the performance of the PTR is predicted with the accompanied thermal losses. The developed analysis code is verified with the experimental results. The effect of the inertance tube length which plays an important role in the PTR is also specifically investigated from the experimental and simulation results. It clearly shows the effect of the flow impedance of the inertance tube on the dynamic response of the piston as well as the cooling performance of the PTR.     

LVDT与RC负载法在线性压缩机性能测试中的对比

针对一台线性压缩机,分别采用LVDT和RC负载法进行了实验研究,实验结果表明:采用RC负载法测量得到的压缩机出口(即回热器入口)PV功与LVDT测量得到的活塞端面PV功之差,占整个输入电功的5%—20%,进一步减小了线性压缩机损失。     

电冰箱节能改进措施研究

通过对电冰箱制冷系统和压缩机的匹配进行优化,最终把电冰箱能耗由原来的0.29 kW.h/24 h降低到0.25 kW.h/24 h。总结此次项目的成功经验为后续节能电冰箱的设计提供参考依据。