Papers by Author: Rui Tian

Abstract: A full size 3D numerical simulation of gas liquid two-phase flow in a submerged membrane bioreactor was carried out. The standard k-ε turbulence model and Euler multiphase flow model of fluent were used. The effect of changed aeration conditions in the reactor on the gas holdup and gas-liquid velocity distribution in the reactor was studied. The simulation results were shown that, at the same aeration rate, the liquid and gas velocities of 1mm hole aerated at the membrane surface increased faster than 2 mm and 3mm aeration holes; At the same aeration hole , with the increase of aeration rate，the liquid and gas velocities at the membrane surface increased; At the 1mm aeration hole and 5.5m³/h aeration rate, the vortex area was larger and gas holdup was higher, so that gas and liquid were contacting well and the membrane surface scouring effect was better; The Simulation also shown that local gas holdup was lower at close to the wall at the bottom of the reactor, this was not conducive to the growth of microorganisms in the activated sludge, the need to further optimize the structure of aeration and reactor.

Abstract: According to the resource characteristics of Chinas western alpine region, the thermal equilibrium experiment and analysis of solar digester is studied in this paper. Under the simulation conditions, the experiment showed that preheating time of solar digester will be shorter with the heat temperature increasing, and the shortest preheating time is 35 min. At the same time the calculation result showed the effective thermal efficiency in preheating stage is gradually increased from 75.7%, 84.6% to 99.3%. In order to maintain the digester thermostat 860 kJ/m³/h heat should be provided to the digester. The digester temperature can be maintained above 33°C within 10 hours in the case of a low humidity in summer. The auxiliary heat sources and additional insulation layer added to the system should be considered in the case of winter and high humidity day in summer.

Abstract: In order to verify the correspondence of numerical simulation and experimental results in the electric heating biogas digester system, an electric heating biogas digester experimentdevice was established, and according to the experimental conditions, software Fluent was used to simulate the process of the heat transfer in the system. Before simulation, analyze theexperimental data through the calculation of heat balance and modify it, then use the modifiedexperimental data, compile UDF to characterize the dynamic boundary conditions, choosestandard turbulence model through the Raleigh number, numerical solving the process. Numericalsimulation results show: simulation process basically reflects the experiment, the simulation dataand experimental data are good agreement, and error within 1%. It is concluded that thenumerical simulation analysis is accurate, method is reliable.

Abstract: A model of BP neural network for road traffic noise prediction was established by using some road traffic parameters in this paper. Then use this model to predict equivalent continual sound level of road traffic noise, After an overview about the neural approach, the learning; and production phase results are shown and contrasted with the measured data. They point out how good is the approach proposed to model noise pollution in urban areas.

Abstract: Investigated at the intersection of zhongshan east road and xilin road in Hohhot, the total quantity of vehicle in morning, noon and evening peak hours is 19,793. Pollutant concentrations and weather parameters are investigated, vehicular emission density in the intersection is calculated by the Nichoson box model, and each pollutant concentration in the intersection is measured by the exhaust gas analyzer. The result shows that the concentration of CO in the intersection is still lower than the limit value, but the concentration of NOX is far higher than the limit value. Pollution is very serious.

Abstract: Membrane bioreactor flow field distribution directly affect effective control of the membrane pollution,and affect the membrane flux greatly. The experiments of membrane bioreactor liquid are measured by using PIV that the measurement areas include membrane bioreactor upper, middle and lower. The experimental data obtained velocity field information through the PIV software analysis. The experimental result indicates that middle of the membrane bioreactor flow field is the most unstable. The experimental measurement result provide membrane bioreactor structure the optimized design, effective control of membrane pollution and raise the membrane flux.

Abstract: natural draft counter flow cooling tower heat and mass transfer numerical simulation has been widely used to optimize the cooling tower design and to improve the thermal efficiency, but in published papers, a few important problems is not attracted attention, such as how does impact grid density to the calculation results; how does impact change of atmospheric density to the calculation results; drop diameter is an important parameter in numerical simulation, but it is not a exact experimental data, it is important to discuss how does impact drop size to the calculation results. This paper will explore and analyze these issues in the numerical simulation.

Abstract: The data of four sets of the sun radiation testing system in Hohhot was processed by the method of standard deviation to get the highest relative accuracy as a model with data. By comparing the measuring value with the calculating value of clear-sky solar radiation model established, it is found the model is only fit for the sunny day, moreover the lager percentage of sunshine is, the model is more appropriate. This model can meet the practical needs of general engineering and also can be used in the analysis of building energy efficiency

Abstract: The solar thermal collector performance evaluation system is designed for the actual needs of tests for industrial production and scientific research, which is adequate for stable efficiency, time constant, incident angle modifier and pressure drop measurement on either end of the thermal collector.

Abstract: In this paper, it has studied membrane fouling experiments at a certain temperature conditions and with untreated tap water as thermal mass, which applied unique multi-layered stacked air-gap membrane distillation module. It has analyzed the original membrane flux and conductivity changes in the experiments, and carried out SEM and EDS analysis before and after acid washed fouling membrane. The results show that: New type membrane module will produce fouling even at lower temperatures. Membrane surface was covered by a lot of uneven accumulation granular pollutants and cuboid crystals, so the mass flux reduced. Fouling membrane washed with 5 % hydrochloric acid solution was removed inorganic scale. The flux recovered to the initial value.