Experimental Performance of Moderate and High Temperature Heat Pump Charged with Refrigerant Mixture BY-3

Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.

Compressional Wave Velocities in Some Volcanic Rocks at Pressure up to 4.5 GPa

Compressional wave velocities in some Mesozoic and Cenozoic volcanic rocks from Qinling Dabie orogenic belt were measured at room temperature and high pressure (up to 4.5 GPa). Compressional wave velocities of these rocks increase with the increasing of pressure. The experiment data indicate that the pressure at which the microcracks in these rocks finally close is up to 2.0 GPa. The empirical relationships between compressional wave velocities at high pressure and oxide mass fractions, heat productions and densities at room temperature and 100 kPa of these rocks are discussed. It is likely that there does not always exist linear relationship between compressional wave velocities and oxide mass fractions. New heat production data of volcanic rock samples from the Qinling Dabie orogenic belt do not follow the empirical relationship between heat production and seismic velocity for rocks. It is dangerous to use these empirical relations to predicate the modal chemical composition, density and heat production of the lithosphere.

Some studies on transient behaviours of sheath formation in dusty plasma with the effect of adiabatically heated electrons and ions

Based on quasipotential analysis, a plasma sheath is studied through the derivation of the Sagdeev potential equation in dusty plasma coexisting with adiabatically heated electrons and ions. Salient features as to the existence of sheaths are shown by solving the Sagdeev potential equation through the Runge–Kutta method, with appropriate consideration of adiabatically heated electrons and ions in the dynamical system. It has been shown that adiabatic heating of plasma sets a limit to the critical dust speed depending on the densities and Mach number, and it is believed that its role is very important to the sheath. One present problem is the contraction of the sheath region whereby dust grains levitated into the sheath lead to a crystallization similar to the formation of nebulons and are compressed to a larger chunk of the dust cloud by shrinking of the sheath. Our overall observations advance knowledge of sheath formation and are expected to be of interest in astroplasmas.

南沙海域沉积盆地及油气资源分布

南海新生代经历过大陆张裂与分离、海底扩张和地块碰撞等构造演化历史,南海北部为被动大陆边缘,南部为碰撞挤压边缘,东部为俯冲聚敛边缘,西部为走滑边缘。南海南部在新生代中期以后为挤压环境,形成张裂盆地、前陆盆地及前弧盆地。南沙海域位于南海南部,区内万安、曾母、北康、南薇、中建南和礼乐等主要沉积盆地油气勘探实践表明,南沙海域具有十分丰富的油气资源,是我国乃至世界上的一个重要油气区。烃源岩、高热流值、挤压构造发育和生储盖条件匹配等是南沙海域沉积盆地油气富集的有利因素。

压缩式热泵在醋酸丁酯酯化工艺中的应用探讨

本文对压缩式热泵在醋酸丁酯酯化工艺中的应用进行的探讨 ,分别就系统的热力性能和经济性进行了分析。计算表明 ,使用热泵可提高系统经济性 ,节能效果显著。

Flow Characteristics of a Refrigerant-Oil Mixture in a Vapor Compression Heat Pump Heat Exchanger for Space Applications

The vapor compression heat pump is considered as the best option for aerospace thermal control system.The heat exchanger in vapor compression heat pump is a component that is greatly influenced by the cosmic environment.Lubricating oil enters heat pump system with a refrigerant under microgravity,and the entrance of the lubricant increases the complexity of the flow.In this work,FLUENT software was used to study the flow and lubricant deposition of a two-phase mixture of lubricant POE RL 68H and refrigerant R134a in a heat exchanger without the consideration of phase-change heat transfer.The functional relationships between the oil film thickness and the proportion of lubricating oil,the gravitational acceleration,the inlet flow velocity,and the placement directions of the two phases of oil in the heat exchanger were established.The results demonstrate that with the increase of the gravitational acceleration and the lubricating oil content,the thickness of the oil film will exhibit an S-type change in line with the Boltzmann function,and the amount of lubricating oil deposition will increase.With the increase of the flow velocity,the thickness of the oil film will exhibit an exponential decline.

Influence of Microstructures and Residual Stress on Fatigue Crack Propagation Rate of High Carbon Steels

The cold-work tool steels T10A and GCr15 have been studied with regard to the influence of austenitization temperature, tempering temperature and the residual stress on the crack propagation rate and the critical crack length. The kinds of fracture morphology have been studied too. The crack propagation rate is dependent strongly on the austenitization temperature, the tempering temperature and the surface compressional residual stress in specimens.