Papers by Keyword: Vaporization

Abstract: This work is devoted to finding of a solution of the actual problem of modern solar power engineering that consists in incomplete conversion of the Planck spectrum of solar radiation using photoelectric conversion. Concentrated solar power being an alternative faces other limiting features such as high cost of building and maintenance, large areas occupied by these plants, the need of precise adjustment of mirrors-lenses systems and also its detrimental effect on nature, birds in particular. An intensification of vaporization from the surface of water can become a solution. In this work a thin layer made of graphene nanoflakes was used as an absorbing media for solar radiation that intensifies evaporation. Also it acts as a catalyst for transmission of water through porous substrate that was made of wood. Results for these experiments were compared with evaporation from free surface. The possibility of using of these porous substrates for the purpose of desalting and purifying water was also experimentally studied.

Abstract: To describe the explosive flow in thin tubes the model of vapor-liquid mixture with heat and mass transfer in two-dimensional axisymmetric formulation is employed. The phase transformation is significantly amplified with increasing of initial saturation temperature. The radial expansion of the jet outflow occurs due to the intensification of vaporization from cylindrical to conical form and parabolic form for supercritical initial state. Another problem applied to the outflow of a detonation wave in liquid filled with chemically active gas bubbles from the thin cylindrical tube. Modeling shows the important role of the opening angle of the outflow jet, which can either support the detonation or put it down.

Abstract: An tungstate ionic liquid (IL) 2-(1-propyl-3-methyl-imidazolium) ([C₃mim]₂[WO₄]), was prepared. The density and surface tension of the IL were determined in the temperature range of (293.15 to 343.15) K. Using Kabo’s method and Rebelo’s method, the molar enthalpy of vaporization of the IL, Δ_l^gH_m⁰ (298 K), at 298 K and, Δ_l^gH_m⁰ (T_b), at hypothetical normal boiling point was estimated, respectively.

Abstract: It takes the C26:33L6 engine as an example to simulate the LNG vaporization system on LNG powered ships. It establishes the dynamic mathematical model of the three-way valve, the vaporizer, the heater and the heat exchanger in LNG vaporization system. Then, the simulation model was established based on MATLAB. At last, it analyzes the LNG temperature at the heater outlet under different loads using the PID control in order to make LNG temperature stable to the engine.

Abstract: The influence of inlet air temperature on penetration, vaporization and combustion of atomized liquid fuel droplets which is sprayed in a stream of turbulent swirling air flow stream located inside taper can gas turbine combustion chamber has been simulated using the commercial Computational fluid dynamics code star CD. It was observed that the variation of inlet air temperature plays a significant role on penetration, vaporization and combustion. The results were presented with help of plot of average temperature and contour plots of turbulent kinetic energy.

Abstract: Modern internal combustion (IC) engines employ a variety of injection techniques for preparing a combustible mixture of fuel and air. In a fuel injection-based system, the vaporization of the atomized hydrocarbon fuel droplets has significant influence on engine performance and emissions. The entropy generation associated with droplet vaporization is particularly important as it is directly related to the destruction of exergy i.e. the potential to produce useful work. Since a fuel spray could involve millions of droplets, solving the entire set of governing equations for individual droplets in a spatiotemporally discretized domain is impractical. The present work explores the utility of a simple phenomenological model in predicting the entropy generation history. The results indicate that this model ensures computational efficiency without much sacrifice in accuracy.

Abstract: Simulation of the launching process in concentration water injection launcher, and get the parameter variations during the launch process, compared with traditional engineering algorithm, verify the reliability of the simulation results, given a new research method of interior ballistics on this launch system. This simulation has very important meaning for the temperature and pressure checking at the Beginning of the design. The simulation results show that,after the flow field stable,the average temperature and pressure in low-pressure chamber and the sabot are very close. This article uses the FLUENT software, use Mixture two-phase flow calculation model to solve the gas-liquid flow field, use the dynamic mesh and UDF program to simulation the flow field.

Abstract: Both treatments and leaching tests of an Mg slag sample containing F of 2.15% from an Mg factory in northwest China were conducted in the present study, focusing on problems of F pollutions. By treating at 1000-1200°C in a muffle furnace, F leaching was decreased to a minimum level of 0.49-2.85 mg/l from the Mg slag with an original F leaching of 13.9 mg/l. The F leaching values increased to 4.83-95.5 mg/l, while treating the slag samples in a vacuum furnace. The treatments of Mg slag may thus be carried out in oxidizing atmosphere and under 1200°C to minimize fluorine pollutions and to improve environmental performances of the Pidgeon process.

Abstract: Pidgeon process is used by more than 300 plants in China to produce magnesium (Mg) metal. Fluorite, ranging 2-3%, is often mixed in raw materials to catalyze the Mg production. The Mg slag from the production then contains F of several mass percent. When the Mg slag is used in construction or treated for recycling, possible F pollutions are of concerns. The present study used slag samples containing F of 0.98-2.15% from an Mg factory in northwest China. Both treatments at 1000-1400°C and leaching tests before and after the treatments were conducted for the slag samples. The study results show influences of the treatments on mineral compositions of the samples, which controlled F contents in both the slag samples and leachates. The results are reported and discussed. Some suggestions are also presented to minimize fluorine pollutions and to improve environmental performances of the Pidgeon process.

Abstract: Power reduction when converting a gasoline engine to propane can be mitigated by designing an injection system so the heat required for evaporation of the propane is drawn from the intake air. Air is cooled and densified, resulting in volumetric efficiency increase. LPG sprays were imaged using Mie and LIF imaging techniques from a port fuel injector, and from long and short connecting pipes. Images were taken in an optically-accessed pressure chamber at atmospheric pressure and fuel pressures of 1.5 MPa. Images of the pipe-coupled injection spray show significant evaporation in the pipe, whose amount depend on the length and diameter of the pipe. The duration of the LPG pulse at the manifold end is, for 300mm pipes, five times the original duration at the injector, and even greater for 600mm pipes. The narrow sprays and the amount of evaporation that occurs before the fuel enters the manifold explains the differences in engine torque and in-cylinder mixture temperature with the different systems.