Hot environmental warm body dummy simulates human safety evaluation analysis

High-temperature environment is common in a scene such as heat treatment operation in industrial production and emergency rescue in emergency rescue. Human body safety in high temperature environments is an important part of public safety research. It is necessary to consider "human-clothing-environment" as a heat system. This system relates to a plurality of physical processes such as thermal radiation between environment and clothing, thermal conductivity inside the apparel, and a plurality of physical processes such as hot logistics and thermal radiation between humans.

Two kinds of human body safety research in high temperature environments, mainly including thermal reaction modeling calculations and live or human simulation experiments: 1) The modeling method of thermal reaction is based on thermal physics principles, the human body-clothing - The thermal reaction calculation model of the environment is calculated by numerical iteration 1. In 1971, the STOLWIJK model application negative feedback control theory established the human thermal reaction model of the 6-section 25 unit, which is considered to be a breakthrough in the human thermal reaction model 2. Huizenga et al. Established a Berkeley model of human physiology and comfort evaluation in a normal temperature complex thermal environment, and 7 improvements in the Stolwijk thermal reaction model, improved the accuracy of simulation calculations 3. Tanabe et al. Based on multi-point heat regulating and radiation model and calculating fluid mechanics, establishing a thermal comfort evaluation method of clothing, and considering temperature non-consistent environments 4. Han Xuefeng et al. Established a multi-layer heat transfer numerical model based on 20-part district sweating heating body dummy equipment. The heat physical parameters of each partition were determined by experiment, etc., establish a thermal balance equation group, and realize the dummy in a given person Temperature changes under thermal stress, and simulation of thermal exchange of clothing 5. The thermal reaction modeling calculation method can simulate the change in body temperature, sweating, breathing, heart rate, etc. in the thermal environment, and has the advantage of time consuming and low cost. Although this method has made great progress, there is still a limitations: considering the fine complex details of the human - environment interaction, such as air turbulence, local air disturbance, temperature and humidity, uneven temperature radiation in the surrounding surface, multi-layer clothing The thermal and material exchange of the system, the evaporation, liquefaction, moisture migration caused by various physiological regulation of the human body, and the effect of human motion on the thermal reaction 6. 2) Method for simulation experiments in live or human body. The real person is difficult to perform under the extreme conditions, and a large number of real people can sum up the thermal reaction law of the human body, improve the cost of the experimental study of the real person; the human simulation experiment study will have a fake person such as heat, sweating. As a core device, the thermophysis response of the human body 7 is simulated 7. Psikuta et al. Experiment and modeling physiologically adjusted fake people with physical and heat, sweating, etc. in normal temperature, but only studied the single human model, not systemic 6. CoCA et al. Is a research tool to investigate the effects of firefighters in the performance of protective equipment 8. Zhen Yuhong et al, developed a sweating in the test system based on the 3D size data of human experiment and human body in the middle and hot humid environmentAnd test and evaluate the thermal wet performance of the clothing 9. By the technical limit, most of the human simulation equipment cannot act on body temperature, sweating, etc. according to the thermal stress of the environment, regulate 10, or only partial instead of body model. However, since the human simulation experiment has the equipment stability, the experimental results can be repeatedly reproducible, and the experimental assessment of accuracy is accurate, it has become a hot spot method for human safety evaluation in high temperature environments.

This paper establishes human safety evaluation methods combined with human body in high temperature environments. Place the hemity dummy in a closed high-temperature environmental experimental cabin, measure the environmental parameters around the human body in real time, and use the thermal reaction model to calculate the human body thermophysiological reaction under the environmental parameter, through the heat of the warmer dummy, sweating The function of this time is realized, and the thermal reaction interaction of the human body is achieved. In addition, through the observation of the changes in the thermophysiological parameters of the human body during the experiment, the safety state of the human body is judged according to the research results of medical students.




Construction of the experimental platform
Experimental platform includes people - machine-environmental simulation subsystem, parameter measurement subsystem and data acquisition / transmission / Processing the subsystem 3. Man-Machine-Environmental Simulation Sub-system Manufactured a specific thermal stress environment by high temperature cabin and hot radiation plate, using the Newton heater dummy to simulate the thermophysical response behavior of the human body, and wear heat protective clothing for the dummy, and then form people - machine-machine-machine- The thermal reactive system of the environment. Basic parameters such as temperature, humidity, and the equivalence of the environment, etc. measure the thermophysiological parameters of the temperature, humidity of the sub-system measured by the parameter. The data acquisition / transmission / processing subsystem consists of data acquisitionr, dummy control software thermogradac, and human body thermal reaction calculation model, and receives real-time measurement results of parameter measurement system, calculates the thermogravure response behavior of the dummy, and transmits the corresponding instruction to NEWTON warm fake people, as a basis for the thermophysis response of human body dummy in the human body.
Thermor dummy is analog equipment for human physiological behavior, and is used to apply to clothing comfort. This experiment is based on the Newton heater dummy produced by Northwestern China, with the heat response results of thermophysiological simulation calculation, and simulates the physical reactions such as body heat and sweating in the thermal environment. Newton warm fake people include dummy and skin layers, external systems, environment sensors, and control software. Among them, the fake person and the skin layer are the external structure of the human body, and in the skin layer, the internal controller and capillary are in the skin layer, as a micro-action unit of the simulated human body heat, sweating; the external system is physiologically heat, sweating and other physiology The corresponding external control box composition, the role of the organs corresponding to the human physiological function.
2, Experimental Scheme
The main idea of human safety research experiments in hot environment is: placing a warm-acting dummy and hot radiation plate in a closed thermal environment experiment cabin, manufacturing a particular thermal environment through hot radiation plates. , Measurement system and environmental parameter measurement system and environmental parameter measurement systemThe system obtains the relevant parameters, and the thermal stress is calculated by the data processing system to obtain the thermophysis response of the dummy under the thermal stress, and the heaters are transmitted to the warm body fake. By real-time fake people's biological parameters, two indicators of body temperature and sweating rate, judge the safety status of the human body. In order to facilitate the research of safety evaluation methods, there is no hot protective clothing in the experiment, but only sweat the skin, with the thermal resistance of sweating skin, the wet resistance parameters replace the heat and wet performance parameters of the hot protective clothing.
The main process of the experiment is: 1) Turn on the heat radiation board, the temperature increase in the cabin; Through the evaporation of sweat; 4) Judging the human safety state by body temperature and sweating, the relevant parameters are greater than the safety threshold, which enters the dangerous state, which is greater than the limit threshold, otherwise it is in a safe state. 3. Calculation of physiological indicators
In the data acquisition / transmission / processing system, embedding the human thermophysiological reaction calculation model, with real-time environment and human hot wetting parameters
are input, iterative calculations The thermophysis response of the human body is obtained. The calculation model uses the model recommended in ISO 7933, the main calculation formula is 11:
1) Calculate the maximum evaporation heat flow EMAX (W / M2) required for the skin surface EREQ (W / M2): EMAX PSK-PARCL, (1) EREQ M-DEQ-W-CRES-RRES-CR. (2)
Where: PSK and PA are saturated vapor pressure corresponding to skin surface temperature and ambient temperature, KPa The RCL is the wet resistance of the skin layer and the garment, M2kPa / W; M is a metabolic rate, W / m2; DEQ is a storage rate, W / m2; W is the human body, W / M2; W is the body temperature, W / M2; W is the human body The external power, W / m2; CRES and RRES are the heat convection rate and heat evaporation rate of breathing, respectively, and W / m2; C and R are thermal pair flow rate and thermal evaporation rate of the skin surface, respectively, W / m2. In the above parameters: PSK, PA, RCL is worthy of measurement; M, W According to the actual situation; other parameters are:
DEQ CSPTCR, EQ, I-TCR, EQ, I-1 · 1-αi-1 (3) CRES 0.01516mTex-TA, (4) ERES 0.00127m59.34 + 0.53TA-11.63Pa, (5) C + r TSK-Taicl. (6)
Where: i is i Time-step, each time step size of 1 min; CSP is human body heat capacity, W / (m2 · k); TCR, EQ, I is the human core temperature, ° C when equilibrium corresponding to the metabolic rate;αi is the skin - core quality parameters; TEX, TA, TSK are exhaled gas temperature, ambient temperature and skin temperature, ° C.
2) Calculate the expected sweating rate Si (W / m2),
Si Si-1 · E-110 + SREQ1-E-110. (7)
where SREQ is the desired sweating Rate, W / M2, its value is determined by EREQ and EMAX.
3) Calculate the rectal temperature Tre, I, ° C,
TRE, I TRE, I-1 + 2TCr, I-1.962TRE, I-1-1.319. (8)
, TCR, i is the core temperature of the human body, ° C,
TCR, I 11-αi2dicsp + TCr, I-1-TCR, I-1-Tsk, I-12αi-1-TSK, Iαi2.
(9) In medical students, the rectal temperature of the human body is used instead of the core temperature 12. Thus, the environmental parameters can be measured by setting human parameters, and the sweating rate and rectal temperature required in the thermal environment can be calculated.
Second, Experimental Results and Analysis

Human hot comfort time TSK 34 ° C 12, set this value as the initial value of the human skin temperature. The temperature TRAD of the heat radiation plate is set to 30 ° C, 32 ° C, 34 ° C, 36 ° C, 38 ° C, 40 ° C, and investigate the thermophysiological changes in the human body in the experiment 4 H, and judge the human body by body temperature and sweating. Security status.
1, rectal temperature change
The change in rectal temperature TRE during the experiment is shown in Figure 4.
1) The higher the thermal radiation temperature TRAD, the faster TRE is increased.
2) When the TRAD is 30 ° C and 32 ° C, TRE will decrease first, and finally reach a more stable value, indicating that the human body can adapt to the thermal radiation; when Trad 34 ° C, TRE is still still there Wave, indicating that this thermal radiation temperature is a critical condition of the human body to the thermal environment, which is consistent with the TSK stable value of 34 ° C; when the TRAD is 36 ° C, 38 ° C, TRE is first growing faster, until The ISO 7933 model is effective calculated critical value Tre 40 ° C (corresponding time t1 98 min), and the thermal response law of the human body has not been calculated using ISO 7933 model.
3) When the TRE reaches a dangerous value, the human body enters the corresponding dangerous state. The danger limits of rectal temperature are physiological sunsimitations 38.5 ° C, safety upper limit 38.9 ° C, tolerated upper limit 39.4 ° C 13.
2, sweating rate change
Analyze the change law of sweating rate S during the experimentTo determine the human body security.
1, the higher the TRAD, the faster S growing;
2, when the TRAD is 30 ° C and 32 ° C, the S will decrease and then decrease, and finally reach a more stable value, indicating that the human body can be adapted Thermal radiation environment; when trad 34 ° C, S is finally fluctuated, indicating that this thermal radiation temperature is a critical condition of the body's adaptation of the thermal environment; when TRAD is 36 ° C, 38 ° C, 40 ° C, S is faster After stabilizing the limit. The control TRE curve can be found that TRE 40 ° C, that is, the experimental time TL 108 min, the thermal response regular of the human body has not been calculated using the ISO 7933 model. At this time, SL 375 ml / (m2 · h), is also calculated The limit value of the sweating rate is obtained.
3, when S is greater than 0.01% (246.33 ml / (m2 · h)), the human body is in a dangerous state of the sweating rate judgment 13.
When the human body can adapt to the heat radiation environment, the dangerous time has gradually shortened with the increase in the temperature of the thermal radiation; when the human body cannot adapt to the heat radiation environment, the dangerous time is basically the same. This shows that when the intensity of the thermal environment exceeds the human regulation capability, the sweating ratio of the human body has a corresponding limit value, and the sweat rate changes around the limit.
4, the total number of people with the human body exists. When the total lost amount σ s exceeds this limit, the human body is in a dangerous state of lossless. When σ s reaches 2% (1.4 kg), it enters the dangerous state; when σ s reaches 5% (3.5 kg) of body weight, the heat hazard state 14.

Aiming at a single theoretical calculation or experimental simulation of the limitations of human safety problems in high temperature environments, this article applies sweating warm body dummy as core equipment , Established a human thermal safety evaluation model combined with the theoretical calculation and experimental simulation. The model can react to the thermal environment, judge the thermal safety state of the human body through the change in body temperature and sweating rate, thereby achieving auxiliary decision function for human safety protection in high temperature environments.
The safety evaluation method also has a certain enough, mainly: 1) The body surface temperature value is weighted by the body surface temperature of 20 borders, and the sweat is performed according to the weight after weighted body surface temperature. Adjustment. More precisely, each of the bosses should be treated, ie, according to the surface temperature of each of the bosses, respectively, and adjust the sweat rate. 2) Experiments in the closed thermal environmental laboratory, the temperature and humidity in the middle of the inside of the experiment change, because this change is directly related to the real-time heat generation rate and sweating rate in real time, so that the experimental results are difficult Unable to consider the theoretical model calculation results of the dummy active thermal response adjustment to

. The next step should be carried out in a constant temperature and humidity environment box, and the results of the experimental results are compared with the theoretical model.The safety evaluation method makes improvements.3) In this experiment, in order to simplify the method, the heater dummy is not hot protective clothing, only the thermal resistance of the protective clothing is replaced by the thermal resistance of the sweat skin attached to the outer layer of the fake.Obviously, the hot and humidity value of sweating skin is much smaller than the corresponding parameters of the thermal protective clothing.The next step should carry out the thermal safety experiment of the high temperature environment after protective clothing.