A local refinement method of unstructured grid generated by bubble packing method (BPM) is proposed. In the present method, different size bubbles are added to the real and artificial vertices of the domain and bubble...
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A local refinement method of unstructured grid generated by bubble packing method (BPM) is proposed. In the present method, different size bubbles are added to the real and artificial vertices of the domain and bubble information of these vertices is transferred to the inner nodes of the domain by the Shepard interpolation method. Moreover, a method to control the population of bubbles is presented to add bubbles in large gap between bubbles and remove bubbles to eliminate overlapping so that the generation of skinny triangles is avoided and the grid quality is clearly improved. Furthermore, the improved BPM is applied to generate unstructured grid with local refinement near boundary for square domain to simulate the lid-driven flow in a square cavity with Re=1 000. The numerical result agrees well with the benchmark solution, indicating that the improved BPM is effective to the computation of fluid flow and heat transfer.
In this work, the vapor pressure equation, saturated liquid density equation, saturated vapor density equation and Helmholtz equation of state for dimethyl ether are developed by genetic optimization algorithm combine...
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In this work, the vapor pressure equation, saturated liquid density equation, saturated vapor density equation and Helmholtz equation of state for dimethyl ether are developed by genetic optimization algorithm combined with a weighted least-square fit of selected experimental data based on extensive collection of DME's experimental data. The average absolute deviation of vapor pressure equation, saturated liquid density equation and saturated vapor density equation is 0.50%, 0.38% and 0.55%, respectively. The uncertainty in density of the equation of state ranges from 0.1% in the liquid to 1% near the critical point.
Elastic capsules (consisting of viscous fluid enclosed by elastic membranes) can form specific adhesion bonds with functionalized surface. Adhesion force in these bonds and viscous and inertial force in fluids determi...
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An experimental study has been performed to investigate pool water instantaneous flash evaporation in a rectangle chamber. Some key parameters such as superheat, initial water temperature and water level have been stu...
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An experimental study has been performed to investigate pool water instantaneous flash evaporation in a rectangle chamber. Some key parameters such as superheat, initial water temperature and water level have been studied. The water level was at 40 mm, 60 mm, 100 mm, 150 mm. Initial conditions of the liquid varied from 36C to 88C temperature and 2.1C to 48C superheat. The experimental results showed that the initial water temperature, the superheat and the water level are the key parameters. The experimental results showed that the greater the superheat and the higher the initial water level approaches, the longer the flashing will persist. Under a constant superheat, the initial water temperature has little influence on duration of flashing. Experimental study allows us to correlate the flashing duration time with the superheat and the initial water level as well as the initial water temperature.
In previous studies, it was showed that the leading point, namely, the positively curved flame front, may be vital in controlling the propagation of flame, thus controlling the burning intensity of turbulent premixed ...
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A finite volume solver for Casson fluid flow based on SIMPLE algorithm of Newtonian fluid on unstructured collocated grid is developed to simulate haemodynamics in complex vessel. The discretization of convective flux...
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A finite volume solver for Casson fluid flow based on SIMPLE algorithm of Newtonian fluid on unstructured collocated grid is developed to simulate haemodynamics in complex vessel. The discretization of convective flux and source term are similar with Newtonian fluid. For the discretization of diffusion flux, viscosity will take the value calculated from the flow field of previous iteration so as to avoid the complexity caused by the complicated viscosity expression as a function of shear rate. Then the discretization of momentum equation is similar with that of Newtonian fluid with variable viscosity and SIMPLE algorithm can be used to resolve the pressure-velocity coupling. With this algorithm, blood flows in a T-typed bifurcation are simulated. The simulation results of Casson fluid are more consistent with experimental data than that of Newtonian fluid, which indicates that using Casson model to simulate non-Newtonian characteristics of blood flow is successful and necessary.
This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is complete...
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This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is completely determined by the basic reproduction number Ro. If Ro ≤ 1, the diseasefree equilibrium is globally stable and the disease dies out. If Ro 〉 1, a unique endemic equilibrium is globally stable in the interior of the feasible region and the disease persists at the endemic equilibrium. Numerical simulations are presented to illustrate the results.
Based on the wavelet analysis theory of signal singularity detection, the critical heat flux (CHF) and minimum film boiling starting point (qmin) of boiling curves can be detected and analyzed by using the wavelet mul...
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Based on the wavelet analysis theory of signal singularity detection, the critical heat flux (CHF) and minimum film boiling starting point (qmin) of boiling curves can be detected and analyzed by using the wavelet multi-resolution analysis. To predict the CHF in engineering, empirical relations were obtained based on genetic algorithm. The results of wavelet detection and genetic algorithm prediction are consistent with experimental data very well.
To investigate the size effect on the characteristics of boiling heat transfer, boiling behavior of FC-72 in heated vertical miniature circular tubes immersed in a liquid pool was experimentally studied. Two AISI 304 ...
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To investigate the size effect on the characteristics of boiling heat transfer, boiling behavior of FC-72 in heated vertical miniature circular tubes immersed in a liquid pool was experimentally studied. Two AISI 304 stainless steel tubes with inner diameters of 1.10 mm and 1.55 mm correspondingly, were heated by swirled Ni-Cr wire heaters and sealed in Lucite blocks by silicon adhesive. Both the top and the bottom ends of the circular test sections were open to the liquid pool. The boiling curves and heat transfer coefficients were obtained experimentally. The boiling behaviors at the outlets of the miniature tubes were also visualized with a digital video camera. Experimental results show that the tube geometry has a significant effect on the boiling characteristics. Vapor blocking at the outlet of the smaller circular tube with a diameter of 1.10 mm caused severe boiling hysteresis phenomena. The CHF decreased with reducing in tube size.
With the booming coal industry and the increasing production of semi-coke, a large number of small particles and powder pyrolysis semi-coke are urgent to be exploited. Co-firing semi-coke with coal is a potential appr...
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