Application of Heaters Dummy in Apparel Hot Wet Comfort Comfort Test

Thermal dummy is an instrument equipment that simulates the human body and environmental hot and humid exchange, and can scientifically evaluate the overall thermal performance of clothing in clothing in clothing hot and humidity, and avoid human body differences in real people. The impact; high experimental accuracy, repetitive, is recognized as an essential means for apparel effects.

Heaters of the warmers

Warmorers are used to simulate The thermal wet exchange process between the human body, clothing and the environment, the performance state of the fake person can be described by surface temperature, heat generating, thermal resistance, and wet resistance. Before experimenting, the accurate and reasonable test scheme and parameters have important significance to grasp the test law and accurate evaluation of clothing hot and humidity.

1, thermal resistance

According to human thermal balance theory and clothing hot wet transmission principle, when sweating, clothing and environment When it is in thermal balance, the production of the fake person is equal to the heat dissipation of the garment 10, ie Q QT + QE (1), Q is the heat-transport flow (W) of the dummy; Qt is the human body through the garment surface. Non-evaporated thermal flow (W); QE is the human body through the evaporative heat flow (W) of the garment surface.

The heat fluid resistance generated due to temperature gradient is referred to as thermal resistance due to temperature gradient.

The total thermal resistance RCT of the clothing has two parts, part of which means the effective thermal resistance value of the clothing, and the other part is to install the surface air layer thermal resistance RCTO, which is exposed. The thermal resistance measured under the same environment conditions, that is, RCT RCF + RCTO.

Considering the impact of the human body surface area increases the thermal transfer characteristics of clothing, the basic thermal resistance of the garment is RCF Rc - (RCTO / FCL)

In (3), the clothing area factor FCL is the ratio of the clothing surface area and the body's net body surface area.

The total thermal resistance of clothing refers to the thermal resistance from the skin surface to the environment, including the impact of the surface area and the impedance of the surface air layer of the body; the effective thermal resistance of the garment is from the skin To the thermal resistance of the surface of the clothing, the influence of increasing body surface area; the basic thermal resistance of clothing is from the thermal resistance of the skin to the surface of the garment, excluding the impact of increasing the increasing human body surface area after dressing. Therefore, for clothing insulation performance, the thermal resistance type and test indicators must be explicitly characterized and comparable to each other.

Warm fake people measuring 3 models of thermal resistance: constant skin temperature, constant heat flow and hot comfort. At the same time, clothing thermal resistanceThere are three models: parallel mode, serial mode, and global mode. Table 1 lists more than three modes.

When calculating the thermal resistance of the garment, in addition to calculating the total thermal resistance of the garment, the local thermal resistance of the costume is also important, because the local thermal resistance can truly express the clothing Some body insulation performance. For clothing of the same fabric, local thermal resistance can also distinguish the subtle differences caused by the clothing structure, which is more advantageous to improve the design of clothing structure.

2, wet resistance

An important factor affecting clothing comfort is the moisture absorbing resistance of clothing, that is, the wet resistance of the clothing.

The total wet resistance of the clothing refers to the wet resistance of the skin surface to the environment. It is similar to dry-based heat transfer, but also considering the increase in human body surface area and wet resistance of the air layer of the garment surface.

Test standards for warmers

Dummy's hot humidity The evaluation of test standards and comfort in terms of test mainly includes clothing thermal resistance, wet resistance testing and comfort evaluation. At present, the test technology of the warm body fake people is quite mature, Table 4 is the international test standard for thermor dummy.

Limitations of warmer dummy test

Testing in warm body fake In the hot and humidity test of clothing, the dummy is an intrinsic factor, and the accuracy of the final test results are left and right. Good precision and simulation performance of the warm body dummy, and the stable dressing conditions and test environment conditions, it is a basic guarantee for obtaining the real test results of the clothing hot wet performance index. However, the fake person is the simulated human heating and sweating mechanism, and there is a certain limitations in technology, which is worth studying.

1, the repetitiveness of the fake people Since the inventions of the sweat, the performance of the sweatythum The dummy system has always been a challenge for researchers. Although there are a variety of forms of warmers, but due to the difference in design, there is a considerable difference in the form of the dummy, resulting in a large change in the results of the same apparel using different dummy tests. At present, the prostitutes have fewer in the world, and all countries have their own characteristics, their body type, material, segmented structure, temperature control method, The sweating method and the experimental method are different, resulting in different clothing utilization There is a big difference in the test results of the warm body fake, limiting the promotion of the dummy.

ingvarholme # 39; R 14 points out that for wet resistance experiment, the variation coefficient is larger, single layer clothingThe variation coefficient of the test results reached 50%, while the variation of variation of multi-layer clothing test results exceeded 100%; 4%, and the variation coefficient of the test results between different laboratories is 5% to 10%, so most of the heaters are currently used for qualitative analysis and comparison. 2, the dummy simulates the problem of sweating

Since the 1980s, the researchers have carried out the exploitation system of the dummy. In addition to researching the sweating of the new structure, the main idea is concentrated on how to pass water into the skin through the pipeline, so that the simulated skin is kept in water. The existing sweating warm body dummy is divided into two basic modes of active sweating and passive sweating. The active sweating system uses a precise amount of water supply system, which is usually combined by the pump and valve, and the water supply can be set in advance, such as 100, 200 g / h, etc., and maintain a constant air supply in the entire experiment, it is Control the skin surface moisture of the dummy skin. The passive sweating system is only the sweat dissipation of the dummy, not quantitatively supply. This water supply method can be seen in the warm body dummy Walter, and the water tonic will automatically change with the different perspective ability of the clothing.

However, no matter which sweat mode is used by the warm body dummy, the fake people simulate the body sweating can be divided into two kinds, one is a completely simulated human body. The sweating state, including the situation of sweating under vigorous exercise, which belongs to the simulation of bionics, but most of the real people sweating does not meet the dummy as the equipment for the equipment of the equipment. For example, the amount of sweat drops along the limbs will not be used to calculate the moistureproof capability of the garment. At the same time, the liquid sweat invaded the garment will seriously affect the insulation of the garment, so the fake people simulate the most ideal state of sweating is Uniformly releases gaseous sweat. So it is necessary to keep the humidity of the dummy skin and do not want the sweat to invade the clothing, which is high for the design and material of the fake human skin.

In addition, in motion state, the body of the body is different. In the coverage area of the apparel, there is also the highest in the underarm and the chest, and the other parts are also different. Therefore, the sweat of the entire human body is considered to be unable to reflect the sweating of the human body, so how to better set the prostitute's sweat to truly simulate the status of live people, it is urgent to solve problems.

Conclusion

Most of the current heaters dummy research is limited to single-layer clothing The human body-apparel-environmental system, it is recommended to consider multi-story clothing systems in the future. After all, we will wear multi-layered clothing in most cases, and the warm body dummy has someQuestion, even if you can sweat, it is just a certain approximation of the human complex heat regulating system. It has a certain difference with the true regulation system of humanity. The test results must be compared with live experiments and conduct comprehensive comprehensively evaluations.I believe that the warmers in the future will be more mature, more widely used in textile and apparel, occupational health, environment, fire, traffic safety, aerospace and other fields. More about:

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