[en] Based on the principle of pressure gradient diffusion, the mechanism of the influence of surface tension on interphase mass transfer was brought forward, and a mathematical description of the influence was presented exploringly. Finally, relating to industrial applications, the influence of surface tension on oxygen deaerating in the atomizing section and in the bubble sections was introduced, and the influence of surface tension on atomizing absorption was pointed out as well

[en] Using the experiment facility for the new type spray-stuffing deaerator, the static and dynamic operating characteristics experiments of the deaerator were carried out, and its operating characteristics were obtained. By means of transforming traditional sprayer into three stream spray and replacing stuff by a swirl vane device, an excellent heat and mass transfer condition was established. The test results demonstrate that the deaerator system has perfect operating characteristics and higher deaering efficiency

[en] Highlights: • Evanescent wave tunneling spectrum in three bodies system with independent temperature has been calculated with the help of rigorous coupled wave analysis. • An intensive quasi-monochromatic tunneling peak has been induced in non-contact. • The tunneling mode originates from the coupling between cavity modes and spoof surface modes, and is further amplified by three bodies effect. • The spoof surface modes originate from surface phonon polariton in SiO₂, and is manipulated by subwavelength structure. - Abstract: In this study, a quasi-monochromatic photon tunneling peak has been achieved in substrate–comb–substrate three bodies system. The near-field tunneling peak results from coupling between spoof surface mode and cavity mode, which has been further amplified by three bodies effect. The spoof surface mode originates from phonon vibration, and is manipulated by the structure into new surface mode. As a non-contact approach to generate high intensity and narrow bandwidth tunneling mode, current study has many application points in near-field spectroscopy and energy-conversion.

[en] Highlights: • Asymmetric radiation transfer in a linear metamaterial with its physical meaning has been numerically demonstrated via Finite-Difference Time-Domain method and Rigorous Coupled Wave Analysis. • The physical picture of the asymmetric light-matter interaction has been investigated. • Dispersion relationship of surface plasmon polariton and temporal coupled mode theory have been employed to verify the results. - Abstract: In this paper, asymmetric radiation transfer based on linear light-matter interaction has been proposed. Two naturally different numerical methods, finite difference time domain (FDTD) and rigorous coupled wave analysis (RCWA), are utilized to verify that asymmetric radiation transfer can exist for linear plasmonic meta-material. The overall asymmetry has been introduced to evaluate bifacial transmission. Physics for the asymmetric optical responses have been understood via electromagnetic field distributions. Dispersion relation for surface plasmon polariton (SPP) and temporal coupled mode theory (TCMT) have been employed to verify the physics discussed in the paper. Geometric effects and the disappearing of asymmetric transmission have also been investigated. The results gained herein broaden the cognition of linear optical system, facilitate the design of novel energy harvesting device.

[en] Two-phase frictional pressure drop of air-water mixture was studied in a narrow rectangular duct with cross-section 40 mm by 1.6 mm. The experimental results show that the conventional correlations fail to predict the two-phase frictional pressure drop in narrow rectangular duct; Lee-Lee correlation which is based on the rectangular duct gives a relatively good agreement with our experiment, but has lower values than the experimental data. Different modified Chisholm correlations were proposed in two regions which were distinguished by the ratio of liquid Reynolds number and gas Reynolds number. The modified correlation has a good agreement with the experimental data. (authors)

[en] Based on visual observation and digital images, two-phase flow patterns in smooth glass tubes under rolling condition were identified. In the paper, effects of tube size, rolling angle and rolling period on the transition between different flow patterns were analyzed in detail. The results showed that with the same superficial liquid velocity, increased tube size, shortened rolling period or decreased rolling angle could make annular flow beginning need higher than superficial gas velocity, and the transition from slug flow to churn flow also need more gas flow rate when tube size and rolling angle decreased, or rolling period increased. Besides, when the superficial gas velocity kept constant and tube size increased, rolling period shortened or rolling angle increased, the transition from slug flow to bubble flow requires more liquid flow rate. (authors)

[en] Experimental studies on single-phase real time flow resistance characteristics under unsteady flow condition were carried out. The experimental phenomena show fluctuation changes friction pressure drop characteristics. The friction pressure drop fluctuates with fluctuation flow and there is phase difference between two fluctuation signals. Based on analysis, such conclusions can be achieved that the acceleration may strongly influenced friction pressure drop, and with the same flow rate, the friction pressure drop is different with different directions of acceleration. When the direction of acceleration is same as that of flow rate, the friction pressure drop is large, when the acceleration is opposite with flow rate, the friction pressure drop is small. Based on theoretical analysis, an empirical correlation was obtained to calculate real time friction pressure drop of fluctuation conditions and calculated results fit well with experimental data. (authors)

No abstract available

[en] In fluid transportation industries, long straight transition pipelines upstream of flowmeters are required to eliminate the influence of disturbed inflow on flow metering accuracy. To ensure an accurate flow measurement, the straight transition pipeline, which is often lengthy, can be shortened, particularly when the installation space is limited. However, the characteristics of disturbed flow (mainly characterized by vortex inflow) evolving along the straight transition pipeline to affect the metrological performance must be investigated for optimizing the pipeline length. The objective of this study was to investigate the metrological performance of a swirl flowmeter affected by the vortex inflow caused by flow regulation with a sleeve valve. The effect of a straight transition pipeline length upstream of a swirl flowmeter on the evolving characteristics of the vortex inflow was investigated experimentally and by conducting a numerical simulation under flow regulation parameters, including valve openings and flow velocities. The flow coefficients for different straight transition pipeline lengths were investigated to verify the flow simulation. The periodic pressure variation in the swirl flowmeter was monitored and its corresponding characteristic frequency was analyzed. It was found that the metrological characteristics of the swirl flowmeter were extremely affected by a smaller valve opening, which can be improved by lengthening the straight transition pipeline. By analyzing the velocity vector and vorticity in the internal flow field, the vortex inflow was found to be vulnerable to dissipation within a longer straight transition pipeline. The average vorticity at the cross-section of the entrance to the swirl flowmeter was adopted to evaluate the inflow vortex intensity. Additionally, a power curve model was established to assess the critical characteristic frequency determined by the maximum unaffected inflow vorticity for different straight transition pipeline lengths. This study can provide helpful insights to the metrological performance and pipeline arrangement in the field of fluid transportation engineering.

[en] A detailed comparative numerical study between the two-dimensional (2D) and quasi-two-dimensional (quasi-2D) turbulent Rayleigh–Bénard (RB) convection on flow state, heat transfer, and thermal dissipation rate (TDR) is made. The Rayleigh number (Ra) in our simulations ranges up to 5 × 10¹⁰ and Prandtl number (Pr) is fixed to be 0.7. Our simulations are conducted on the Tianhe-2 supercomputer. We use an in-house code with high parallelization efficiency, based on the extended PDM–DNS scheme. The comparison shows that after a certain Ra, plumes with round shape, which is called the “temperature islands”, develop and gradually dominate the flow field in the 2D case. On the other hand, in quasi-2D cases, plumes remain mushroom-like. This difference in morphology becomes more significant as Ra increases, as with the motion of plumes near the top and bottom plates. The exponents of the power-law relation between the Nusselt number (Nu) and Ra are 0.3 for both two cases, and the fitting pre-factors are 0.099 and 0.133 for 2D and quasi-2D respectively, indicating a clear difference in magnitude of the heat transfer rate between two cases. To understand this difference in the magnitude of Nu, we compare the vertical profile of the horizontally averaged TDR for both two cases. It is found that the profiles of both cases are nearly the same in the bulk, but they vary near boundaries. Comparing the bifurcation height z _b with the thermal boundary layer thickness δ_θ, it shows that z _b < δ_θ(3D) < δ_θ(2D) and all three heights obey a universal power-law relation z ∼ Ra ^−0.30. In order to quantify the difference further, we separate the domain by z _b, i.e., define the area between two z _b (near top and bottom plates respectively) as the “mid region” and the rest as the “side region”, and integrate TDR in corresponding regions. By comparing the integral it is found that most of the difference in TDR between two cases, which is connected to the heat transfer rate, occurs within the thermal boundary layers. We also compare the ratio of contributions to total heat transfer in BL–bulk separation and side–mid separation. (paper)