Study On Heat And Mass Transfer Absorption Performances Of Absorber With Vertical Tube Bundle And Metal Wire Mesh

Under the theme of energy saving and environmental protection, energy resources become increasingly tense and the situation is even more severe. Under this background, it is well known that absorption refrigeration system can directly use low grade energy, such as industrial waste heat and solar energy and other low grade energy, so it has attracted more and more attention. NH3-Li NO3 and NH3-NaSCN, as two new working pairs, compared to the LiBr-H2 O absorption refrigeration system, it can obtain lower evaporation temperature; Compared to NH3-H2 O absorption refrigeration system, it doesn't need distillation device.Absorber is the core of the whole refrigeration system, and its absorption ability directly determines the trend of the refrigeration performance of the whole system. Therefore, it is necessary to design reasonable structure of the absorber, and study its absorption ability when it is filled with NH3-LiNO3 and NH3-NaSCN working pairs, identify the step optimization method. And finally, we can find out the method of optimization design.This paper summarizes the theoretical basis of falling film flow and this two new working pairs. Reference to the domestic and foreign relevant experimental system, the workgroup design and set up a experiment system, which includes data acquisition and control. By controlling the absorber solution entrance parameters and cooling air entrance parameters, the workgroup tested the macro absorption performance of the absorber. The conclusion shows that the spray concentration, spray temperature, spray flow rate, absorption pressure and cooling air volume have a great influence on the absorption ability; As the spray flow rate increases to 0.014kg/(m·s), the influence gradually becomes smaller; As the absorption pressure increased from 210 Kpa to 335 Kpa, NH3-LiNO3 and NH3-NaSCN heat and mass transfer coefficient can be increased 18% and 20%. By setting up tube falling film flow physical model and mathematical model of the vertical tube, and dividing grid nodes of the liquid film flow area and setting boundary conditions, an iterative calculation is made. The velocity field, temperature field and concentration field of the whole flow field are obtained by the previous calculation, the concentration difference on both sides of the liquid membrane is close to 13%, and the temperature difference is close to 6, so we can study the mechanism of heat and mass transfer process from the microscopic point of view. The conclusion shows that the mass transfer process is mostly occurred in the upper portion of the falling film absorption and near the gas-liquid interface side.This paper mainly studied absorber of heat and mass transfer process through the experimental study and numerical simulation, explored the most important influencing factors on the absorption ability, and calculated the heat and mass transfer performance of the two new working pairs. Finally, this paper also analysis the shortcomings of the test-bed, provides a theoretical basis and experience for the future design of the absorber and the overall system.