Study On Heat And Mass Transfer Performance Of Modular Contactor For Dehumidification And Humidification

With the improvement of people’s living standard,people pay more and more attention on the comfort of indoor environment.Indoor air quality affects people’s work efficiency and quality of life.Temperature and humidity in proper range make people’s daily life and work environment be in a state of comfort.The bad air quality reduces people’s comfort,and even affects people’s health.Low indoor air humidity makes people feel dry and beeasy to suffer from respiratory diseases.The immunity also declines,so the control of air humidity is particularly important.In this paper,a modular hollow fiber membrane contactors is designed and fabricated.It reforms the structure of the conventional hollow fiber membranemodule.It shows advantages in reducing the manufacturing cost and maintenance cost with module’s performance unchanged.The major work in this study is as following:1.A hollow fiber membrane module with semi-random,semi-regular structure was designed and manufactured by using the self-developed hollow fibers.In this paper,five hollow fiber membrane modules with different packing densitieswere selected for experiments and numerical simulation.The water is used to humidify the air through heat and mass transfer between two sides of membrane.The air and the water are contacting in cross flow pattern.The packing density of small elements in the assembled hollow fiber membrane module was 35%and 50%,respectively.2.Based on theobservation,the elements showa dual scale characteristics.A predictive model is built according to this characteristics and it is validated against with the experiment data.Experimental results and simulation results show that the model shows accuracy in certain range of working condition.3.The humidification performance of different elements and pressure drop are simulated with the numericalmodeland are tested via the experiment platform.The result shows that the increase of air flow rate increasesthe mass transfer coefficient of the elements,but the humidification efficiency is reduced and the pressure drop increases.The increase of inward area introduces the negative effect to the performance of the element.A set of optimum running and geometry parameters for this novel contactor are suggested as following:packing density=0.5,Re=0-100,S_w=20 mm,S_T=32 mm.4.Compared with other types of membrane contactors,the new type hollow fiber membrane module is of high maintainability,simple design and good scaled-up performance.