Research On Enhancement Of Heat Transfer And Shell Side Flow Field For Recombinant Tobacco Concentrated Heat Exchanger

In the process of Reorganization tobacco production extract heat exchange steps has an important influence on the quality of the tobacco slice, must be considered of heat transfer efficiency and performance, the shell side of heat exchanger geometric structure directly affect the performance of heat exchanger, shell side of heat death zone will affect the heat transfer performance, a high temperature will lead to side fouling phenomenon inside the tube area, increase the thermal resistance of heat exchanger. For the heat transfer process of tobacco extract, in this paper, uses ultrasonic anti-fouling heat transfer enhancement methods and CFD technology, study of heat transfer ultrasonic cavitation anti fouling experimental, and from heat exchanger shell side flow distribution and temperature distribution starting to simulate and optimize of shell-side heat exchanger geometry to solve restructuring concentrated tobacco the efficiency and performance of the heat exchanger to provide technical support.(1) Analysis of the mechanism of tobacco extract in the heat exchanger fouling, using ultrasonic cavitation effect to study the anti-fouling, increasing the model cavitation in the shell and tube heat exchangers, simulating different ultrasound frequency of beam tubes bubble volume fraction distribution, bubble volume fraction higher than the previous cycle peak in each vibration cycle, the role of cavitation will be getting stronger; the ultrasonic device installed in comparative experiments on the device to get the tobacco extract physical parameters shorter rise time, significantly improving the efficiency of heat transfer equipment.(2) Establishing and analyzing heat exchanger geometric structure flow field model, discussing the different turbulence models in the applicability of the heat exchanger CFD calculation process. Results show that the spalart-allmaras one-equation turbulence model has obvious defects in the numerical simulation of heat exchanger performance, standard k-ε turbulence model and k-ε turbulence model achieve to better applicability, through to investigate total heat exchanger and shell drop, CFD calculations can be achieved closest with the Bell-Delaware equations design theoretical value under the realizable k-ε turbulence model, stronger than the other two models numerical simulation capability.(3) With the baffle block cut rate decreases, the fluid flow area of the main focus on the longitudinal extension of the deflector of the window, the fluid flow change position increasingly close to the next baffle, while gradually increasing the recirculation zone, mainstream area velocity flow rate is much higher than other regions, velocity distribution inhomogeneity more prominent, using the better applicability realizable k-ε turbulence model to calculate, assessing the relevant data in the two case of cut rate, to obtain heat exchanger performance is the best in a block cut rate of 25%.