Experiments are conducted to investigate the characteristics of single-phase forced-flow convection and boiling heat transfer of R113 flowing through annular tube with gap of l, 1.5 and 2.5 mm. and also the visualizat...
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Experiments are conducted to investigate the characteristics of single-phase forced-flow convection and boiling heat transfer of R113 flowing through annular tube with gap of l, 1.5 and 2.5 mm. and also the visualization test are carried out to get two-phase flow regime. The data show that the Nusselt numbers for the narrow-gap are higher than those predicted by traditional large channel correlation and boiling heat transfer is enhanced. Based on the data obtained in this investigation, correlations for single-phase, forced convection and flow boiling in annular tube of different gap size has been developed.
The dynamic characteristics of molten droplets and hot particles at the very beginning of their fall into coolant pools are presented. The falling course of a single droplet or a single hot particle was recorded by a ...
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The dynamic characteristics of molten droplets and hot particles at the very beginning of their fall into coolant pools are presented. The falling course of a single droplet or a single hot particle was recorded by a highspeed camera and a curve of velocity vs. time was obtained. Emphasis was placed on the effects of the droplet's size and temperature, the coolant's temperature and properties, and the droplet's physical properties on the moving behavior. The results for the all cases showed that the velocity of a falling droplet/particle decreased rapidly but rebounded shortly, at the beginning of droplet/particle falling in the coolant. Following such a V-shaped evolution in velocity, the droplet/particle slows down gradually to a comparatively steady velocity. An increase in either coolant temperature or droplet temperature results in a larger velocity variation in the 'J-region', but a smaller deceleration when it moves out of the 'J-region'. The elevated volatility of a coolant leads to a steeper deceleration in the 'J-region' and beyond. The bigger size of a particle leads to a greater velocity variation in the 'J-region' and terminal velocity. A high melting point and thermal conductivity as well as lower heat capacity contribute to dramatic variation in the 'J-region' and low terminal velocity.
Accurate measurement of trace heavy metal mercury(Hg) in flue gas of coal-fired units is great significance for ecological and environmental *** gas was used to simulate the actual flue gas of a power plant in this st...
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Accurate measurement of trace heavy metal mercury(Hg) in flue gas of coal-fired units is great significance for ecological and environmental *** gas was used to simulate the actual flue gas of a power plant in this study.A laser-induced breakdown spectroscopy(LIBS)system for Hg measurement in mixed gas was built to study the effect of mixed gas pressure,Hg concentration in mixed gas and delay time on Hg *** experimental results show that the appropriate low mixed gas pressure can obtain high Hg signal intensity and signal to noise *** Hg signal intensity and signal to noise ratio increased with the increase of Hg concentration in mixed *** Hg signal intensity and signal to noise ratio decreased with the increase in delay *** to the above results,the optimized measurement conditions can be *** Hg concentrations in mixed gas were quantitatively analyzed by the internal standard method and traditional calibration method *** relative error of prediction of the test sample obtained by the internal standard method was within 11.11%.The relative error of prediction of the traditional calibration method was less than 14.54%.This proved that the internal standard method can improve the accuracy of quantitative analysis of Hg concentration in flue gas using LIBS.
The purpose of this paper is to study the characteristics of the combined convection heat transfer and a micropolar nanofluid flow passing through an impermeable stretching sheet in a porous *** nanofluid flow field i...
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The purpose of this paper is to study the characteristics of the combined convection heat transfer and a micropolar nanofluid flow passing through an impermeable stretching sheet in a porous *** nanofluid flow field is affected by a magnetic field perpendicular to the *** dynamic viscosity of the micropolar nanofluid changes under the influence of the magnetic *** continuity,linear momentum,angular momentum,and energy equations are first simplified using the order of magnitude technique that,along with the applied boundary conditions and the definition of the appropriate parameters,are transferred to the similarity space using the similarity *** the resulting equations are solved using the Runge–Kutta *** distinction of the macroscale and microscale flow fields and temperature fields resulting from different nanoparticle shapes was *** the Hartmann number,the vortex viscosity parameter,the magnetic parameter,the nanoparticle volume fraction,and the permeability parameter of the porous media increased the surface friction on the *** the vortex viscosity parameter,the magnetic parameter,and the volume fraction of the nanoparticles increases the Nusselt number.
The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of ...
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The corrugated packing is prone to break down easily, which can affect the tower efficiency substantially. It is the inner environment of the vacuum distillation tower including the temperature and chemical nature of fluid that lead to the packing damage. The theoretical analysis indicates that it is the inner material flow of vacuum distillation tower that leads to the vibration of packing, which can affect the corrosion fatigue of packing significantly. Meanwhile, the modal shape and inherent frequency of packing under prestress can be obtained by means of mathematical analysis. Based on the two kinds of analysis, the flow induced vibration and corrosion fatigue are accountable for the failure of packing.
The accurate prediction of subcooled boiling phenomena in narrow rectangular channels is of great importance for the plate type fuel reactor core safety analysis during some critical scenarios. Serious of experimental...
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Series of experiments have been performed at different pressures from 12 to 19 MPa, mass velocities from 400 to 1000 kg·m-2· s-1, inner wall heat fluxes from 300 to 500 kW· m-2 and bulk fluid enthalpy f...
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This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critic...
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This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critical radius under different conditions was extracted using the image processing *** with the existing critical Peclet number theory,the dominant factors of flame instability under current conditions for three n-alkanes can be figured ***,the average cell size(equivalent cell radius,R_(cell))was extracted to provide quantitative analysis of the flame cellular structure,based on the method developed in this *** theoretical R_(cell)were also calculated and compared with the experimental results to validate the proposed method.
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