To improve the cognition of humidity regulation characteristics, the flow field data of fresh-keeping environment when ultrasonic humidification device works were collected and resh-keeping transportation envelope based on the structure of differential pressure principle and equipped with oranges was studied. A three-dimensional turbulence model of 1/4 ratio envelope was established and numerical simulation of ultrasonic humidification is obtained using hole and component transmission models and fluent software, combined with SIMPLE algorithm with wall function method. The temperature and humidity changes in the compartment body were analyzed. The results showed that ultrasonic humidification could increase relative humidity from 70% to 90% in compartment body within 212 seconds. Temperature and humidity field distribution in compartment body was uniform while the difference of temperature was less than 1 ℃ and the difference of relative humidity was no more than 3.5%. The humidification process showed a little influence on temperature. The difference of relative humidity of different goods surface was less than 3% and water vapor in goods area diffused faster. Experimental validation showed that test results were in good agreement with simulation results. The results had a certain reference value for optimizing humidification of fresh-keeping transportation equipment.
