In this paper an artificial neural network (ANN) is used to correlate experimentally determined heat transfer rate of non-continuous helical baffle heat exchangers. First the heat exchangers with three helical angles were experimentally investigated under different inlet volumetric flow rate and temperature. The commonly implemented radial-basis function (RBF) neural network is applied to develop a prediction model based on the limited experimental data. Compared with correlations, the RBF network exhibits superiority in accuracy. The satisfactory results suggest the RBF network might be used to predict the thermal performance of shell-and-tube heat exchangers with helical baffles.
MgAl-NO3 LDHs were prepared by hydrothermal method. The as-prepared samples were characterized by SEM, XRD and FT-IR. The adsorption performance of MgAl-NO3 LDHs to methyl orange (MO) was studied. The effects of Mg/Al molar ratio on the adsorption performance of MgAl-NO3 LDHs were investigated. The results showed that the highest adsorption capacity of 499.98mg/g was obtained when the Mg/Al molar ratio was at 2.5:1.
The ripple tray is a sieve tray without downcomers, in which the liquid contacts with the upward gas counter-currently. The hydrodynamics performance in ripple tray columns was investigated with the computational fluid dynamics (CFD) method. Various superficial gas velocity and liquid loads were simulated for the tray with cylindrical cross sections using the Euler-Euler method. The modeling results were validated by comparing the calculated liquid height on the ripple tray with the experimental values. The developed CFD model is found to be able to predict the two phase flow patterns in ripple tray columns and provide useful information for further design of ripple tray.
In this paper, experimental performance comparison of shell heat transfer is made between shell and tube heat exchangers (STHXs) with segmental baffles and non-continuous helical baffles. The helical angles contain 7°, 13°, 25°, which are smaller than the experiment made before. The experiment is carried out in the large-scale experimental equipment with the inner shell diameter, 500 mm and effective tube length, 6 m., which is larger than the previous experimental setup in the scale. The results indicate that the shell side heat transfer rate per unit pressure drop of non-continuous helical baffles is higher than that of traditional segmental baffles at the same volume rate. It is found that with the helical angle increasing, the shell side heat transfer rate decreases.
The project is aimed at describing the mixing phenomena of the new reactor. The solide catalyst deposit on the surface of tubes which affect the flux of the reaction product liquid. The liquid scouring effect is necessary which is relate to the velocity of surface tubes. The new design structure i.e.solide catalyst and liquid in a stirred reactor has been simulated using computational fluid dynamics model (CFD). The arrangement of tubes creat a great effect on the behavior of the fluid, especially the veclocity of surface of tubes. The tank with draft dubes or not have obvious different on the power cosumption and the distribution of solid particles. Power consumption is also taken into account. Compared with Japonic reactor, the design reactor is energy saving which have good potential development.
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