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Common types of Comfortable Thermal Manikin

2021-09-28 11:48
Comfortable Thermal Manikin is an instrumentation that simulates the heat exchange process between the human body and the environment. According to the heat dissipation characteristics of various parts of the human body, the warm body dummy is generally divided into head, chest, back, upper limbs, hands, abdomen, legs and feet. Warm body dummy is a new biophysical test method gradually developed from the 1940s, and is widely used in the fields of clothing, occupational health, environment, firefighting, petroleum, traffic safety, aerospace, construction, etc. Common types of warm body dummies include.

1、Warm body prosthetic head and prosthetic limbs

In recent years, domestic and foreign scholars have developed warm body prosthetic head, prosthetic hands, prosthetic feet, etc., which are mainly used in helmets or headgear, gloves, shoes to evaluate and guide product development. The warm body prosthesis head consists of head, face and neck, and the three parts are heated separately and controlled independently. In order to simulate sweating, the prosthetic head includes 25 sweating holes distributed on the face and head, distilled water located in the water tank above the prosthetic head is fed into the prosthetic head through a pipe, and the sweating volume is controlled by a separate valve up to 70 g/h. The prosthetic head can work in constant temperature and constant heat mode, and the test results indicate the thermal comfort performance of the helmet by the degree of temperature drop on the face. The warm prosthetic hand consists of eight blocks, namely thumb, index finger, middle finger, ring finger, little finger, palm, back of hand and wrist. The heat supply of each block is controlled by computer. The warm body prosthetic hand is placed inside a small box, and the wrist is exposed outside. In real life, the hand is always moving, especially outdoors, so a certain airflow is introduced inside the box, and finally the heat transfer coefficient and local heat transfer coefficient of the glove are used to express the thermal insulation performance of the glove. The heat transfer coefficient is lower in the palm and back of the hand, followed by the index finger, middle finger and ring finger, and highest in the thumb and pinky finger. The heated prosthetic foot consists of eight pieces, namely the toes, sole, heel, mid-foot, ankle, lower calf, mid-calf, and protective segment. To simulate sweating, the prosthetic foot includes five sweat glands, located in the toes, sole, ankle, instep, and lateral ankle. A cotton sock was placed on the dummy foot in order to allow water distribution to the whole foot. The evaluation indexes are thermal resistance, moisture resistance and moisture permeability index. If connected to a pneumatic piston, it can also imitate human walking.
Comfortable Thermal Manikin

2、Dry state warming dummy

Dry state warming dummy can work in three ways: constant temperature method, variable temperature method and constant heat method. Constant temperature method is to control the body surface temperature of each anatomical section of the Comfortable Thermal Manikin in the set range, so that the Comfortable Thermal Manikin into a dynamic thermal equilibrium state, in order to get stable experimental results, the way used to measure the thermal resistance of clothing; variable temperature method is based on the thermal regulation model of the human body in a cold environment, simulating the change in body surface temperature of real people in different environments, the steady-state body surface temperature is not a set value, but the same as real people The result of natural equilibrium, the same can be obtained very similar to the thermal resistance of the garment measured by the constant temperature method, and the variable temperature method has the significance of physiological evaluation that approximates the real person [18]; the constant heat method is based on the thermal resistance of the garment and environmental parameters, with a set value of heat flow to observe the differences in heat dissipation in various parts of the body, when the body surface temperature gradually decreases until it is stable. Including static warming dummy and dynamic warming dummy.

3, sweating warm body dummy

Because the dry state warm body dummy can only simulate the physiological response of the human body in the non-evaporative heat dissipation range, people have developed a sweating warm body dummy. Early sweating warm body dummy is covered with a layer of cotton fabric or other moisture-permeable underwear to simulate human skin, first distilled water sprayed onto the simulated skin, and then put on the clothes, so that the average body surface temperature of the dummy rose to a certain level, the control system every 5 minutes on the dummy body surface temperature, environmental parameters and heating power recorded once, and calculate the evaporation resistance of clothing, in the simulated skin began to dry The test is completed before the simulated skin starts to dry. Because this process is a quasi-steady-state process, usually for a short time, mainly relying on the operator's subjective judgment of which the relatively stable evaporation resistance value as the test results, so this method can not be very accurate, repeatable measurement of the evaporation resistance of the garment.

4、Breathing Comfortable Thermal Manikin

Breathable warm body dummies are mainly used for indoor work environment research and indoor air quality assessment [34~36]. The breathing Comfortable Thermal Manikin has the same body size as an ordinary person and consists of 25 heating zones, each zone is heated separately and controlled independently, and the dummy can change its posture and move freely to imitate the real situation of the human body in various offices, and the Comfortable Thermal Manikin is dressed in a tight-fitting way because the clothes can reduce the thermal radiation between the zones and the influence of the room air temperature on the heat transfer coefficient during correction, and then the clothes can reduce the thickness of the air layer between the clothing and the dummy surface to minimize the measurement uncertainty. The breathing warm body dummy can work in three ways: ① comfort mode, which simulates the dry state heat dissipation and body surface temperature of an ordinary person who maintains a comfortable state in a thermal environment; ② constant temperature mode, where the body surface temperature of the dummy is 34°C; ③ constant heat mode, which is used for the evaluation of the indoor temperature above
34℃ when the thermal environment is evaluated. The comfort mode can represent the actual temperature distribution of the human body and is widely used. Respiratory warming dummy has an artificial lung, consisting of a cylinder equipped with a piston, the piston is driven by an electric motor, the number of breaths is 10-12 times / min, breathing can be oral or nose breathing, lung ventilation capacity of 6 liters / min, the size and shape of the mouth or nose has an impact on the test results, the test, collect the air exhaled at 0.01m from the upper lip or near the face, by accurately measuring its concentration, the temperature and humidity to study the transfer of pollutants between bodies. The same test of the above parameters of the exhaled air of the Comfortable Thermal Manikin can evaluate the indoor air quality.

5、Warming dummy with water immersion

Submersible warm body dummy is based on the warm body dummy, plus a waterproof sealing device, so that the dummy has a waterproof function. Mainly used to test diving suits, water life jackets in the cold environment of the protection function. Test, the dressed dummy immersed in water, keep the water temperature constant, record the dummy skin surface temperature, ambient temperature and the heating power of each zone, calculate the total thermal resistance value of the diving suit, when the total thermal resistance value including underwear, diving suit, water and air thermal resistance. The experiment proves that the total thermal resistance of the diving suit obtained by the submerged warming dummy matches the total thermal resistance value measured with a real person, turbulence will greatly reduce the total thermal resistance of the diving suit, and the height of the water wave can also reduce the total thermal resistance of the diving suit. The thermal resistance values measured by the submerged warm body dummy can also be used to predict the endurance time of the suit in a given environment.

6、Numerical warming dummy

Warm body dummy due to the complex manufacturing process, and expensive, dummy experimental conditions such as the high cost of artificial climate chamber, only a few laboratories in the world have. The use of "virtual" dummies on computers for ergonomic studies can result in significant cost savings. Recently, due to the rapid development of computer computing speed, computational fluid dynamics (ComputationalFluidDynamics, CFD) technology has been increasingly used in various industries, the use of computer technology to simulate the human body has also become possible. In contrast to the traditional warm body dummy, this computer simulation of the dummy is called numerical warm body dummy, and the simulation of heat and mass transfer around the dummy is achieved by solving a series of partial differential equations. If specific environmental parameters and thermal properties of the clothing are input, the numerical warm body dummy can calculate all the heat dissipation such as conduction, convection, radiation and evaporation of the human body, and predict the local temperature and heat transfer coefficient of the human body, as well as the sweat distribution of each part, so as to evaluate the thermal comfort and air quality of an environment.

7、Small Comfortable Thermal Manikin

The small warm body dummy is mainly used to evaluate the thermal environment of newborns, especially low weight infants. It generally consists of six heating zones, namely, head, left upper limb, right upper limb, trunk, left lower limb, right lower limb, each zone is heated separately and controlled independently. To simulate the actual situation, the small Comfortable Thermal Manikin lies flat in the incubator, and its testing method is the same as that of the large Comfortable Thermal Manikin. Since the weight of infants is larger than the proportion of body surface area than adults, the dry state heat dissipation of small warm dummies is larger than that of large warm dummies, and its evaluation index thermal resistance is not much different compared with that of large warm dummies. 
Thermal environment test simulation manikin exchange heat from the external environment by simulating the real physiological mechanism. Combining the dummy monitoring results with the software data analysis results to get the different thermal comfort effect through the protective clothing on the manikin.

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