Research On Optimal Design Of Temperature Control Incubator Based On Temperature Field Simulation

This topic mainly takes the typical temperature-controlled logistics packaging box as the research object,and uses the computer finite element simulation as the research tool to establish the coupling temperature field of the cold storage type incubator and the melting temperature field of the phase change coolant,and explore the pre-cooling temperature of the cold storage agent.The influence of the temperature control effect of the incubator is optimized to optimize the pre-cooling temperature of the coolant under different actual conditions to prolong the holding time of the log tank.At the same time,the numerical model is used to study the influence of different thermal insulation materials on the temperature control effect of the thermal insulation box.The optimization design of the thermal insulation material provides a reference for practical application.In this study,the medium-sized EPP incubator(26L)with the highest frequency of recycling was selected as the research object.The temperature range of 0℃～8℃ was used as the heat preservation interval.The CFD finite element simulation software was used to simulate the flow field in the incubator.And simulation experiments,the results are as follows:(1)Establish a numerical model of the EPP incubator and verify its reliabilityThe geometric model of the box and the coolant was established using SCDM software,and the finite element numerical model of the EPP insulation box and the phase change coupling model of the refrigerant were established based on Fluent.The law.Through the verification experiments,the consistency between the simulated and actual values of the instantaneous temperature and holding time at the same test points were respectively verified,and it was confirmed that the numerical model can objectively predict the temperature distribution inside the incubator,and provide data for subsequent simulation experiments.support.(2)Study the effect of the pre-cooling temperature of the cold storage agent on the temperature control effect of the insulation box under different external temperaturesBased on the temperature field model of the EPP incubator,under the external conditions of 23℃,30℃,and 40℃,get the relationship between the different pre-cooling temperature to the temperature rise rate and the relationship between the temperature return time.In the end,a rule was obtained that when the pre-cooling temperature of the coolant was lower than a certain threshold,the circulation of air flow inside and outside the box would be intensified and the heat exchange with the external environment would be accelerated,but the insulation effect would be weakened or even worse.At 23℃,the temperature of the regenerative temperature is below 50min,and the pre-cooling of the regenerator is-4℃.The pre-cooling of the regenerator above 50min is-9℃.It is best to precool the refrigerant at-9℃ at 30℃.Pre-cooling of the cold storage medium at a temperature of 40℃ below 20min is-7℃;precooling of a cold storage medium at a temperature of 20min or more is-12℃.(3)Simulation experiment on the effect of different insulation materials on the temperature control effect of the insulation boxFive kinds of insulation boxes of three types of materials,EPS,EPP,and XPS were selected,and a finite element temperature field simulation experiment was performed based on Fluent.The temperature field cloud diagrams and temperature distribution maps of the insulation boxes of different materials were obtained.The insulation effect:XPS(30kg/m3)≈ low-density EPS(12.8kg/m3)>low-density EPP(31kg/m3)>high-density EPS(23kg/m3)>high-density EPP(54kg/m3),indicating that the quality of the insulation effect depends largely on whether it is good or bad Depending on the level of thermal conductivity.For the optimal selection of insulation materials,if the temperature control performance of the insulation box is pursued,but the mechanical properties and recycling requirements are not high,the price can accept about one hundred yuan,and the XPS box can be selected;if the required cost is minimized,its mechanical properties are not considered For recycling and environmental protection,an EPS box should be selected;an EPP box should be selected in consideration of its insulation performance,physical and chemical properties,and environmental friendliness.