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Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

T-shaped elbow structure, which is widely used in petrochemical industry, is an important factor to induce pipeline vibration. It is of great significance for the long-term stable operation of pressure pipeline to clarify the flow field characteristics in the elbow. A simulated industrial pipeline was designed and assembled. A 60° T bend made of plexiglass was used in the observation section, and the secondary flow characteristics of the fluid in the pipeline were measured by three-dimensional particle image velocimetry (PIV) system and pressure sensor. The distribution and migration of eddy current in pipeline at different flow rates were analyzed by flow diagram and velocity vector diagram. The results show that a pair of periodic alternating oscillating vortexes of varying sizes appear, increase, decrease and disappear in one period in the 60° T bend, which has some characteristics of the Carman vortex street and Dean vortex. The alternating frequency of these two vortexes increases exponentially with the increase of the flow velocity, and the amplitude of the fluid pressure pulsation increases with the increase of the flow velocity, but the vortex law in the front of the pipeline is basically unchanged. The RNG k-ε model combined with QUICK upstream interpolation method and SIMPLE coupled pressure-velocity equation was used to simulate the variation of secondary flow on the side of the pipeline, and the simulation results are in good agreement with the experimental data. The research results provide a theoretical basis for clarifying the law of pipeline vibration induced by eddy current in T-shaped elbow and optimizing the preventive measures. [ABSTRACT FROM AUTHOR]

To study the effect of the outer bank slope types on the hydraulic characteristics in sharp bends, a threedimensional hydrodynamic mathematical models was developed to simulate the flow structures under different slope types of the outer bank in the Shishou sharp bend section of the Jingjiang reach. The results show that, with the same cross-sectional area and water depth, the gentler the slope can move the maximum longitudinal velocity and the outerbank reverse secondary flow away from the outer bank and the riverbed. The gentler slope can also decrease the turbulence intensity and the main secondary flow scale. Comparing to the simple and composite riverbank with the same slope, the maximum longitudinal velocity remained almost the same but the main secondary flow scale increased and the pairing model of secondary flow were changed. The maximum shear force on the composite riverbank was 1. 2 times larger than that on the simple riverbank, and thus, the composite riverbank was more vulnerable to erosion and damage. Moreover, the turbulence in the upstream of apex of bend was weakened, while in the downstream of apex of bend was intensified. The results can deepen our understanding of the effect of bank slope types on the flow structure in sharp bends, and provided a basis for the protection of different types of bank slope. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the influence of the deflector layout on the performance of mine-used main fan diffuser, the RNG k-ε turbulence model was applied to numerical simulation of the internal flow fields under three inlet velocity conditions with and without deflector. The influence of the central angle and starting angle of the deflector on the performance of the diffuser was investigated. The results show that for the diffuser without deflector, a serious flow accumulation phenomenon exists inside the flow field, which restricts the performance improvement of the diffuser; when the center angle of the deflector is small, the larger the starting angle of its installation is, the higher the diffusion efficiency of the diffuser under the three inlet velocities considered, however the secondary flow due to the uneven pressure on the upper and lower sides of the deflector head appears at some starting angles, which results in an increase in flow losses. As the center angle of the deflector increases, the flow accumulation inside the diffuser improves gradually, and the secondary flow also gradually weakens. When the center angle reaches 60°, the diffusion efficiency is the highest.

Fluid flowing through a curved channel wiil produce a secondary flow phenomenon on its cross-section. Viscoelastic fluid and Newtonian fluid have different flow characteristics. The viscoelasticity of the fluid can strengthen the secondary flow in the bend pipe. In order to explore the influence factors of the viscoelastic fluid on the secondary flow in the bend pipe, the FLUENT software was used to numerically simulate the secondary flow characteristics of the viscoelastic fluid in the bend pipe, and the viscoelasticity of the fluid was realized by UDF. The effects of Weisenberg number Wi, solute viscosity ratio β, and pipe geometry on the strength of the secondary flow of viscoelastic fluid were studied. The simulation results show that there is a non-monotonic relationship between the Wi number and the intensity of the secondary flow in the pipe. The greater the viscoelasticity of the fluid, the greater the velocity of the main flow in the pipe, thereby enhancing the secondary flow effect in the pipe. The geometric structure of the channel such as the curvature ratio and the number of bends have a greater impact on the secondary flow. The greater the curvature ratio, the stronger the secondary flow in the pipe. The study of secondary flow in bend pipe has certain reference significance for strengthening convection and heat transfer by using bend pipe in engineering. [ABSTRACT FROM AUTHOR]

The excellent separation performance of spirals is attributed to its unique characteristics of flow field. Changing the structural parameters of the spirals will exert significant impact on the flow field characteristics in spirals. The simulation experiments were conducted to investigate the water field characteristics under the condition of three kinds of cross-sectional curves with the turbulence model of RNG k--ε and the multiphase model of VOF model. The influence of cross-sectional curves on the flow spreading, distribution of velocity and flow regime was investigated systematically. The results show that the secondary flow is stable when the mesh number is 849200. The flow layer is changing continuously along with the radial position except the condition of n = 2. The tangential velocity is negatively correlated with the parabolic exponent at the inner and middle trough, and positively correlated with the parabolic exponent at the outer trough. With the increase of exponent, the radial velocities of inward flow decrease, however the secondary flow in the middle trough will be strengthened firstly and then weakened with the increase of exponent. Meanwhile the secondary flow intensity in the outer trough is strengthened accordingly. The Reynolds number increases linearly from inner to outer. The distribution width of the laminar flow extends with the increase of exponent, which is conducive to the motion and separation of fine particles. The results can provide a reference for the cross-sectional geometry design of spirals. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to enhance the heat transfer performance of CO2 heat pump, based on the numerical simulation method of Fluent, the law of supercritical CO2 cooling and heat transfer characteristics and secondary flow in the horizontal elliptical tube whose torque is 100 mm or one infinity number under different mass flow are studied. In addition, concerning part coefficient of heat transfer and pressure drop brought by vertical elliptical tube, the influence of the length of the axial ratio b/a and the torque on the heat transfer performance is studied. Simulation results show that, the effect of buoyancy on the twisted elliptical tube is significantly larger than that of elliptical tube under low mass flow, and for the elliptical tube when supercritical CO2 is under the low mass flow G200 kg/(m2·s2) , the twisted elliptical tube has a greater intensity of periodic secondary flow caused by self-structure, and the enhanced heat transfer is more pronounced; the heat transfer coefficient and pressure drop increase with the increasing degree of twist and flattening. It provides important theory and data support for the application of the twisted elliptical tube in CO2 heat pump.

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to optimize the design of kerosene gel supply pipeline and tapered injector, the power-law constitutive model is used to build a solution method of two-dimensional/three-dimensional incompressible steady flow. The flow characteristics of kerosene gel are numerically studied based on a SIMPLE algorithm. The analytical solution of parameters of propellant in straight round pipe and the kinetic energy correction coefficient of laminar flow are presented. The results show that the plunger flow area of straight round pipe is fixed when pipe diameter is unchanged. To reduce the average apparent viscosity of the injector outlet cross section, the length of outlet section needs to be decreased. The reasonable contraction angle of injector is about 40°. In elbow pipe, The secondary flow in the form of double vortices exits in elbow pipe. The asymmetries of shear rate and apparent viscosity are more significant than the asymmetry of flow velocity. [ABSTRACT FROM AUTHOR]

An abstract of the article "Numerical study of effect of buoyancy on heat transfer of supercritical aviation kerosene in a horizontal tube" by Wang Yan-hong and colleagues is presented.