T-junction is widely used as a phase separation component to separate two-phase flow because of its simple structure and low cost. Previous studies suggest that an increase in the number of T-junction branches is conducive to raise phase separation efficiency. In this paper, the pressure distribution and phase separation performance of two-phase flow of R134a in horizontal double T-junctions are studied. The phase separation performance between two branches is compared. The parameters including inlet quality (0.3-0.6), inlet mass flow rate (10.0 g s−1-25.0 g s−1), diameter ratio (1, 0.75) and the distance between two branches (0.3 m-2.6 m) are studied. The inlet mass flow rate has significant influence on the phase separation, and the separation performance reaches best when it is 10.0 g s−1. Results show that the change of parameters has greater influence on the phase separation performance of the second branch compared with the first branch. When the distance between branches is 2.0 m, the total phase separation capacity of the branches reaches the best. By comparing the phase separation of branches, it can be found that when the distance increases gradually, the phase separation performance of the second branch first increases and then decreases, indicating that there is a specific distance that maximizes the gas phase separation efficiency of branches. The optimal distance is also related to the mass flow ratio of the second branch. Therefore, an empirical correlation equation which can accurately predict the gas phase separation efficiency of the second branch is proposed.

T junction, which is regarded as an effective solution to phase separation of air-water, has already been widely applied in industry sector, especially in thermodynamic cycles for improving cycle performance. However, the research on constituent separation of organic refrigerants in the T-junction is just emerging without clear understanding on mechanism, variation and application. In this paper, the constituent separation performance of organic refrigerants, R134a/R600a, in horizontal branch T-junctions is numerically investigated. The computations are conducted based on the Eulerian method with the k-epsilon turbulence model, which has been used to predict phase separation and an agreement is concluded. The inlet mass flux and qualities are 200 kg m(-2).s(-1) and from 0.1 to 0.4, respectively. Based on the model, detailed phase and constituent distribution in T-junction are obtained and then discussed. Furthermore, the separation efficiencies of R134a are analysed based on calculation results. The results show that an agreement is observed on the separation efficiency with the inlet quality varying from 0.123 to 0.286 by comparing with the experimental results. When the inlet quality is 0.4, the inconsistency between the simulation results and the theoretical results and the experimental results may be due to two factors: changing of flow patterns and mass transfer of constituents. (C) 2020 Elsevier Ltd and IIR. All rights reserved.

Because of the simple structure and low cost, T-junction is used extensively as a separation component in energy and chemical systems to lift system efficiency. Recently, it is found that T-junction can also be used for constituent separation of zeotropic mixtures, which can further improve the system efficiency. The phase distribution in T-junction is a complex phenomena due to the complicated influencing factors. To get a clearer understanding about it, this paper firstly gives a comprehensive review on the current experimental progress of impacting T-junction. The effects of all kinds of parameters on phase distribution are investigated thoroughly. Secondly, the theoretical prediction models on phase separation are summarized. Then, the latest research on constituent separation is summarized. This paper concludes that the distribution of constituent separation is based on phase separation. But the research on constituent distribution is extremely limited. Finally, the working principle and specific function of T-junction in some new concept configuration are illustrated by concrete examples enumeratively. (C) 2019 Elsevier Ltd. All rights reserved.

In this work, experiments were carried out to compare the phase separation performance of double branching T-junction with that of single branching T-junction. The inlet and outlet branches of double T-junction were arranged horizontally with the inner diameter of 8 mm. R134a was used as the working fluid. The inlet mass flow rate (mass flux) was set at 10, 15, 20, 25 g s(-1) (199, 298, 398, 497 kg m(-2) s(-1)) and the inlet quality was set at 0.3, 0.5, 0.7 respectively in the experiment of single T-junction. It is concluded that the inlet mass flux has little influence on phase separation while the phase separation efficiency drops sharply with the increase of inlet quality, which is consistent with the conclusions in literature. The experimental data is also compared with the predicted values generated by theoretical models based on air-water and it is found that there is no model suitable for refrigerants. Furthermore, a comparative study between single T-junction and double T-junction was carried out from two perspectives: separation performance comparison of different branches and comparison between single and double T-junctions. The results show that the double T-junction performance is greatly affected by inlet quality and mass split ratio of the first branch, and not always higher than that of single T-junction for horizontal arrangement. Finally, predicting equations of outlet quality of double T-junction are correlated based on experimental data, which have a high predicting accuracy under the high mass split ratio conditions.

As a promising separator, T-junction can be easily incorporated into the thermodynamic systems. Previous researches have investigated the phase separation of air-water and pure refrigerants but here the separation performance of mixtures at horizontal branch T-junctions is reported. Experiments were conducted to explore the effects of the flow conditions, the mass fractions and the geometric structures on the phase separation of R134a/R600a. During the experiments, the flow parameters including the inlet mass flux, the vapor quality and the mass flow ratio of the branch to the inlet, were varied. Three mixtures with R134a mass fraction 0.3030, 0.5202 and 0.7053 were employed. Furthermore, for the configurations of branching T-junction, the diameter ratio of the branch to the inlet was set to be 0.75 and 1.0, and three branch angles (45°, 90° and 135°) were considered. From the generated data, it was found that the branch outlet quality is always higher than the inlet quality, and the vapor fraction of branch outlet decreases with the increase of inlet vapor quality. The higher the mass flow ratio is, the larger the vapor fraction of R134a/R600a is. Under the experimental conditions, the mixtures with R134a mass fraction 0.3030 and 0.5202 have lower vapor fraction than R134a at inlet quality 0.1–0.5. As for the geometric effects, when the mass flow ratio is relatively large, more vapors usually prefer to flow into the branch with the smaller diameter, and vapor fraction for the angle 45° is lower than those for angles 90° and 135°

为了使喷射器适应更广的运行范围、获得更佳的引射率或升压比,从结构改进入手提升喷射器性能在近年来成为研究热点.文章通过文献综述的方法,对现有喷射器结构改进在设计、模拟和制冷应用层面的研究进展进行了梳理.首先,对喷射器结构改进设计中应用的数学模型进行了归纳;其后从几何特征和流变特性两方面,对结构改进后的喷射器模拟研究进行了汇总,梳理了喷嘴出口位置、喷针位置和混合室长度等结构要素对喷射器性能的影响;最后,对结构改进喷射器应用于制冷领域中的代表性实验研究也进行了回顾.文章对喷射器结构改进技术发展的回顾与展望可服务该领域内工程实践的深化.

As one of the separation components, T-junction is widely used in the field of energy for phase separation so as to improve system efficiency because of its compact size, simple geometry and low cost. However, because of the complexity of influencing factors affecting the phase separation law of T-junction, there is not a systematic conclusion having been summarized by scholars on the law of phase separation in branching T-junction. This paper gives a comprehensive overview of the influencing factors on phase separation in branching T-junction based on the experiments and theoretical models. Firstly, the existing experiments on phase separation in branching T-junction are reviewed. Secondly, the pros and cons of the classical theoretical prediction models of the fraction of phase taken off are summarized. Then, the knowledge gap and development prospects of T-junction are summarized. This paper points out that a promising development exists in multiple T-junctions, phase separation of refrigerants and micro-T-junction and much more work on the law of separation, mechanism and theoretical model is supposed to be carried out in the future. At last, applications of T-junction are summarized.

The influence of low-energy low-dose electron-beam irradiation on the light emitting diode(LED)has been studied in this paper.Using the space electron-beam irradiation simulated by ion-beam emitted from experimental accelerator,the LED emitting different color light were irradiated under the different electron irradiation dose.We compare the optical and electronical character results of the intial and irradiated LED.The results demonstrate that the light intensity of irradiated LED increases,and the disctrete property of the statistical light intensity of plenty of LED is better.During the current accelerated aging experiment,the light intensity of the irradiated LED trends to significant decreasing compared with the intial LEDs.Using the electron beam irradiation mechanism the experiment results are discussed and analysed.