回油量对螺杆式压缩机性能的影响

介绍螺杆式压缩机中冷冻油的作用及回油量的计算和测试方法。在确定的名义工况下，测试回油量与制冷量、功率和压缩机性能系数（COP）的关系，分析回油量对螺杆式压缩机性能的影响，并通过试验确定最佳回油量。该研究对螺杆式压缩机的设计和性能优化具有指导作用。     

压缩机润滑油控制系统优化改造

介绍并分析了单试油泵电机过程中氧压机因油压低而自动停运,氧压机油泵无法实现自动切换,以及空压机、膨胀机油压报警设定值不合理导致油泵自动切换失败的故障,阐述具体解决办法和效果。     

Development of a high efficiency refrigeration compressor

In order to improve the energy efficiency ratio of small reciprocating hermetic compressors the following factors are investigated: clearance volume, bore and stroke, rod length ratio, geometric dimensions of a piston and valves and superheat of suction gas.A prototype machine is developed based on this investigation. The reliability of this new type of compressor is confirmed and its energy efficiency ratio reaches 3.02 J W⁻¹ s⁻¹, which is 25% higher than the average value of our current machines.     

Influence of interstitial admixtures on phase transitions in invar

We investigate the influence of hydrogen and carbon on the kinetics of magnetic and atomic ordering in N36 iron-nickel Invar alloy. It is shown that alloying by carbon (up to 0.33wt. %) results in an increase of the CurieT _c and KurnakovT _k temperatures. In the case of hydrogenT _c decreases butT _k remains constant. We determine the optimum carbon concentration (0.17%) improving the operational properties of Invar and propose a physical mechanism of the influence of interstitial admixtures on the temperature coefficient of linear expansion and on the Invar strengthening of N36 alloy. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 34, No. 4, pp. 100–106, July–August, 1998.     

Influence of polymer admixtures on the turbulence structure of flow behind a grating

Experimental investigations of the action of small (20–80 ppm) polymer admixtures on the turbulence structure in the wake behind a grating are performed in a water channel of closed type. The velocity fluctuations are measured by using a single-component Doppler laser velocimeter (DLV). A signal from the DLV was recorded on magnetic disc from three channel sections and the onedimensional energy and dissipation spectra were computed therefrom. It is shown that polymer insertion resulted in reduction of the turbulence level at short ranges from the grating and its increase far from the grating. Influence of the polymer in the spectral distribution appeared in an energy increase in the low-frequency domain and its fast degeneration in the high-frequency band, accompanied by contraction of the spectrum width.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 4, pp. 550–556, April, 1990.     

Influence of surfactant admixtures on the acoustic characteristics of a closed hydraulic loop

Results are presented of measurements of the friction drag, acoustic spectra of pipeline wall and pump pedestal vibrations as well as of the hydrodynamic noise during the motion of a fluid with surfactant admixtures of different nature in a closed hydraulic loop.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 5, pp. 771–777, May, 1990.     

输气系数对压缩机选型宽余率的影响

利用压缩机的热力性能模拟程序,计算分析陈列柜用低温往复式压缩机变工况运行时输气系数、制冷量及输入功率的变化规律,定量地给出在不同冷凝温度、蒸发温度下输气系数对压缩机性能的影响。由分析得出：冷凝温度的提高和蒸发温度的降低均使压缩机的制冷量和性能迅速降低;蒸发温度对压缩机性能的影响相对冷凝温度的影响要大得多。     

冷冻油对螺杆式压缩机滑阀容量调节机构可靠性的影响与分析

介绍螺杆式压缩机的滑阀容量调节机构的原理,分析冷冻油对其可靠性的影响。冷冻油的物理性能差异导致滑阀卸载力大小不同,从而影响滑阀容量调节机构的可靠性。试验结果表明：减小毛细管的孔径或增大滑阀在吸气端的受力面积可有效解决低黏度的冷冻油对滑阀容量调节机构的卸载可靠性的影响。     

卧式旋转式压缩机供油系统CFD模拟及优化

为优化卧式旋转式压缩机供油系统及其装配工艺性,采用CFD方法对某型号卧式旋转式压缩机的供油系统进行三维模拟,深入分析其供油机制,提出更适合量产的优化方案——中间开孔供油风扇,并对优化方案进行CFD模拟和试验验证。结果表明优化方案能够保证供油,满足压缩机的可靠性要求。     

Numerical study on the lubrication oil distribution in a refrigeration rotary compressor

For a rolling piston rotary compressor, oil supply into various lubrication elements has been analytically studied. The lubrication system, consisting of centrifugal shaft pump, radial oil feeding holes, bearings with grooves and some other sliding surfaces has been modeled by employing equivalent electric circuit network. A computer simulation program has been developed to solve the network model of the lubrication system. Its numerical solutions include total oil flow rate into the shaft inlet, oil flow rates in the main and sub journal bearings and in the eccentric bearing, and oil leakages through roller end clearances into suction and compression chambers. Validation of the numerical simulation has been made by the measurement of the total oil flow rate into the shaft. With the aid of computer simulation, parametric studies have also been carried to investigate the effects of the bearing groove shape and groove inclination angle on the bearing oil flow rates.     

Influence of valve dynamics on compressor performance

The valves of piston compressors can cause volumetric losses if they do not function properly and these losses originate from the condition where the force of valve springs differs from the optimal force which can be calculated from equations (1), (2) and (3).This problem is particularly critical with suction valves and the purpose of this report is to determine the factors which influence these losses.These determinations were realised via a series of computer simulations giving various operating conditions. The results show that the gas force A* (equation (1)) and the Mach number Ma* (equation (5)) determine the level of losses for a given force difference. Fig. 4 shows the kind of volumetric losses that can be expected. The most critical conditions occurred with a low A* value and high Mach number, hence careful attention should be given to dynamic design for such conditions.This study has revealed that unnecessary losses can be avoided if spring forces are maintained at about 50 to 150% of the optimal force of springs.     

Foaming of refrigerating oil in a rolling piston type rotary compressor

This paper is concerned with foaming of refrigerating oil in a rolling piston type rotary compressor for an air conditioner. Factors causing foaming during the starting operation were investigated experimentally. It was proved that foaming was caused by the stirring of the refrigerant-oil mixture with a motor rotor, a vane and a discharge refrigerant flow. The foaming was correlated with the solubility of refrigerant in oil and with the amount of refrigerant contained in the stirred region of the liquid mixture.     

Performance of a semi-hermetic reciprocating compressor with propane and mineral oil

The experimental performance of a semi-hermetic reciprocating compressor working with propane as the refrigerant is reported in the present paper. Tests have been performed both with and without an internal heat exchanger between the vapour suction line and the liquid line, at different settings of the expansion valve. The suction vapour superheating is shown to improve volumetric efficiency and, therefore, global compression efficiency.Experimental results are discussed and explained by means of the high solubility of propane in the mineral oil used as the lubricant, which can cause an excessive reduction of the refrigerant-oil mixture viscosity at low suction superheating. Besides, the possibility of condensation on a cold spot inside the cylinder has also been considered.A modified version of the empirical model by Pierre (1982) for the prediction of volumetric and global compression efficiencies is proposed for propane.     

Influence of nonisothermicity of the medium and polymer admixtures on a turbulent vertical wall jet

The results are given on an experimental investigation of the effect of small polymer admixtures and density inhomogeneity of the ambient medium on the laws of development of plane, vertical, turbulent wall jets.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 4, pp. 533–539, April, 1990.     

上下排气结构对空调压缩机效率的影响

本文的研究对象是目前家用空调器广泛采用的滚动转子式压缩机,通过理论与经验的结合,分析影响压缩机效率的一些主要因素,其中着重阐述上下排气结构对于压缩机效率的影响,CFD软件分析及s压缩机实际测试明确上下排气结构对于压缩机效率提高的效果.     

基于实验的螺杆式压缩机容积效率计算方法

建立一种基于实验数据的螺杆式压缩机容积效率计算模型,该模型可以在很宽的运行工况范围内较准确地预测螺杆式压缩机的容积效率,在回归数据范围内,预测最大误差小于1%。     

Influence of admixtures on the crystallization and morphology of AlPO4 crystals

The influence of various uni-, bi-, tri- and tetravalent admixtures on the crystallization and morphology of AlPO₄ has been studied in detail. AlPO₄ crystals were synthesized under hydrothermal conditions. It was found that the phase formation and morphology vary with the type of admixture and its concentration. The crystals were hexagonal, rhombohedral, rounded, irregular, rod shaped and massive in habit. With an increase in the concentration of admixtures, two phases (berlinite and metaphosphates) of the respective admixtures crystallize simultaneously.     

Influence of titanium admixtures on the structure and physicomechanical properties of niobium

On the basis of experimental investigations, we analyze the effect of temperature on the phase composition and microstructure of VN-10 alloy. We study some mechanical (σ_u, σ_0.2, and δ), including long-term strength, and tribological (mass wear) characteristics of a niobium-titanium alloy. We have established that alloys of the Nb-Ti system are characterized by the dispersion-soluble type of strengthening. In the course of oxidation of the alloy in air, oxides of complex structure and texture are formed. Under dry friction, the alloy is more wear resistant after oxidation than after annealing. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 2, pp. 65–70, March–April, 2007.