Research On Thermal Insulation Of Cold Clothing Based On Simulation Test

The static thermal resistance under the environment of 20 ?,relative humidity 65%,natural convection(wind speed <0.1 m/s)is evaluated the thermal insulation performance of clothing.The thermal resistance of cold clothing is affected by the wind speed,temperature,relative humidity and air gap.The daily wind speed and temperature are higher,so the original method is limited.So,to test the thermal resistance of the cold clothing under the actual temperature and wind speed is necessary.In addition,the relationship between the combination of the inner and outer fabrics and the middle insulation material and the insulation performance of the finished product was discussed to provide a basis for the cold clothing design.Simulate common cold clothing' structure,and combine the coat,2 kinds of down feathers with different thicknesses and kapok batt with 4 kinds of fabrics with different air permeability to test the thermal resistance in an artificial climate warehouse.The main research contents and conclusions were as follows:1.Combine 4 insulation materials and 4 surface fabrics to become16 kinds of simulated cold clothing,which were tested at different wind speeds and temperatures,the conclusions were obtained:(1)thermal resistance of cold clothing was highly affected by the thickness and the fiber stacking structure;(2)The thermal resistance increased with the increase of the wind resistance of the outer fabric,and the range was related to insulation;for the kapok floc and woolen velvet products with a small pore size,the thermal resistance varied little with the outer fabric;for down feathers with large pore sizes,the thermal varied a lot;(3)When there was no air gap under the clothing(the clothing was close to the body),the thermal resistance was negatively correlated with the wind speed and the temperature,and the wind speed at low temperatures had a greater impact on the thermal performance;the thermal resistance in windy environment was less than the thermal resistance during natural convection in the laboratory.2.To study the effect of the air gap under the cold clothing on the thermal resistance,combine1 inner fabric,2 thermal insulation,and 3 surface layers to obtain 6 combined textiles with or without air gap,the results showed that:(1)The air permeability of the combined textiles was slightly smaller than the air permeability of single-layer material.When the three-layer combination was used,the inner and outer layer fabrics were reduced.The air permeability of any layer could significantly decrease the air permeability of the assembly to improve the convective thermal resistance.(2)The relationship between the air gap thickness and the thermal resistance of the cold clothing was obviously affected by the wind resistance;for cold clothing with good wind resistance,the thermal resistance increased first and then decreased when the thickness of the air gap increased.When the air gap thickness was 11.3 mm,the thermal resistance was the largest;when the air permeability was relatively large,the thermal resistance decreased when the air gap thickness increased.(3)Under static conditions,the thermal resistance of the cold clothing increased with the thickness of the air gap;Under dynamic conditions,the contribution of the air gap to the thermal resistance was affected by the combination of its wind resistance,structural compactness,and the wind speed.When the wind speed was low,the air gap made a large contribution to the thermal resistance;for cold clothing with poor wind resistance,after the air gap was added under the strong wind,if the insulation layer was a compact structure,the air gap provided a positive insulation effect,and if the insulation layer is a fluffy,and the air gap provided negative insulation;(4)The thermal resistance of the air gap(excluding the thermal resistance of the clothing)was affected by the environment and air permeability.The thermal resistance of the air gap was positively correlated with the temperature;under static conditions,the thermal resistance of the air gap was nearly constant;under dynamic conditions,for cold clothing with good wind resistance,the change of the thermal resistance of the air gap with the increase of wind speed was small;for cold clothing with poor wind resistance,the thermal resistance of the air gap decreased significantly.