Research On Dehumidification Characteristics Of Ultra-low Temperature Manipulator Cold Storage Air Management System

With the development of biomedical technology,the research and development of ultra-low temperature manipulator cold storage is put on the agenda.When the manipulator cold storage frosts,there will be problems such as the decrease of refrigeration efficiency,the recognition error of manipulator,the movement obstruction and so on.In this paper,an air management system is designed for the ultra-low temperature manipulator cold storage to reduce the harm of frosting.ANSYS Fluent is used to analyze the refrigeration dehumidification and adsorption dehumidification in the system.In this paper,a combined air dehumidification system is designed and built,and the experiment of adsorption dehumidification process is carried out.The experimental results show that insufficient cooling time will cause a sharp rise in the outlet dew point when the working state of the adsorption tower is switched,and extending the cooling time can reduce the fluctuation amplitude of the outlet dew point.Taking the two adjacent fins and refrigerant pipes in the evaporator inlet area of the refrigeration dehumidification system as the research object,the numerical analysis of the dehumidification process is carried out by using ANSYS fluent and Lee model.The results show that there is backflow on the leeward side of the pipe,the air temperature is lower,and the condensate is mainly distributed on the leeward side.The phase change heat transfer process of wet air inlet velocity in the range of0.5 ? 2 m /s is simulated.It is found that the heat transfer and heat transfer coefficient of pipe and fin increase with the increase of flow velocity,and the average moisture content at the outlet increases rapidly at the inlet velocity of 0.5 ? 1.0m/s,and then slowly.When the inlet velocity is 0.5 m/s,1.0 m/s and 1.5 m/s,and the wall temperature is 268 ? 278 K,it is found that the influence of the wall temperature on the dehumidification effect at low velocity is greater than that at high velocity.In this paper,the UDF of energy and mass transfer in adsorption process is compiled,coupled with ANSYS fluent porous media model,and the adiabatic,non thermal equilibrium and non steady mathematical model is established.The results show that the adsorption rate of the adsorbent gradually decreases with the increase of time,and the adsorption capacity gradually loses after adsorption saturation,and the outlet moisture content changes in the adsorption time of 2921 s;The temperature field of gas-solid two-phase cannot reach instantaneous equilibrium,the closer to the inlet,the greater the temperature difference.With the increase of axial distance,the temperature difference decreases.The results show that the larger the particle diameter is,the more uneven the adsorbent utilization is and the shorter the effective adsorption time is.The adsorbent with 4 mm Diameter should be preferred.The influence of adsorption temperature on the adsorption performance was studied.By comparing the simulation results with the initial adsorption temperatures of 290 K,320 K and 340 K,it was found that high temperature would reduce the adsorption performance of the adsorbent,prolong the mass transfer zone,increase the outlet moisture content,and maintain the temperature at 280 ? 290 Kduring the adsorption process could reduce the influence of high temperature.The smaller the ratio of height to diameter,the more uneven the utilization of adsorbent and the shorter the effective adsorption time.