Numerical Simulation And Energy Saving Analysis Of MVR Falling Film Evaporator

The evaporation condensation process in chemical industry, metallurgy,medicine, desalination, waste water treatment, pharmaceutical, food and other industrial production is widely used. However, the process of evaporation and concentration of energy consumption is very high, with the rising price of energy,energy saving and consumption reduction of evaporation process is very important.MVR technology energy-saving potential is huge, multi effect evaporation technology,TVR evaporation technology will gradually replace the traditional. Will become the development direction of evaporation technology. The characteristics of flow and heat transfer characteristics of the topic for the MVR of falling film evaporator is discussed by theoretical analysis and numerical simulation.The research work according to the heat transfer and fluid mechanics basic theory, two kinds of heat transfer model is established through the vertical tube falling film evaporation process, two kinds of model for each film by simple gravity model(model I) and film by gravity and the two steam shear force model(model II). In the calculation model was simplified reasonably, on the basis of through discretization of governing equations and numerical solution method of reasonable, The use of VB language application software for the calculation of the evaporator tube,Falling film evaporation heat transfer characteristics of development. Using classic data from case verified software outputs the result is reasonable.Analyzed the change rule of the thickness of liquid film, heat transfer coefficient along the flow direction of the evaporation tube using the software of quantitative development, effect of two kinds of models on calculation results were compared.The results show that the calculation model is in model I, II the results more consistent with practical. Further quantitative analysis of the influence of calculation of falling film evaporation tube segment number of calculation results. The results show that the calculation more segments, calculation precision is higher, but the segment number is greater than the 5~6 segment, the calculated result has little change.The development of application software carried out in actual engineering(in a falling film evaporation engineering dilute 10 t/h solution, for example) indicates that the development of the software is successful. More on the shortcomings of current MVR systems, a new type of process and process is put forward, and a qualitative analysis of the superiority of the new technology. Finally, puts forward the problems in the development of calculation software and suggestions for improvement.