An under-clothing air flow thermal protective performance evaluation device

Abstract

The application discloses a device for evaluating the thermal protective performance of airflow fabric under clothes, which comprises a control system (1) for providing a heat source, a cylindrical skin simulator (9) and an airflow monitoring system (14) under clothes; the upper end of the cylindrical skin simulator (9) is provided with uniformly distributed fabric clamping devices (11), the fabric clamping devices (11) are provided with sliding rails (12), the sliding rails (12) are fixed with the cylindrical skin simulator (9), the surface of the cylindrical skin simulator (9) is embedded with skin simulation sensors (10), the skin simulation sensors (10) are electrically connected with a data acquisition and processing system (17), and the surface of the cylindrical skin simulator (9) is provided with a fabric warp heat shrinkage scale (24); the airflow monitoring system (14) under clothes is used for monitoring the airflow velocity and temperature in a human clothing system and is connected with the data acquisition and processing system (17). The device can accurately predict the thermal protective performance of a dressed human body under different airflow conditions under clothes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of evaluating the thermal protective performance of flame-retardant fabrics, in particular to an undergarment airflow fabric thermal protective performance evaluation device. BACKGROUND

[0002] In the "human-clothing-environment" system, the factors affecting the thermal protective performance of clothing are very complex, mainly including the clothing itself, the air layer under the clothing, and the external heat source. The basic performance, thermal physical parameters, and structural characteristics of flame-retardant fabrics will affect the heat transfer inside the fabric. When the flame-retardant fabric is made into a garment and worn on the human body, the air permeability of the fabric, the movement of the human body, and the like will affect the heat transfer in the form of airflow under the clothing.

[0003] In experimental research, small-scale tests are widely used. Usually, it is assumed that the heat transferred by the heat source to the surface of the fabric is one-dimensional, and a copper heat flow meter different from the skin properties of the human body is used as a skin simulator, which cannot truly simulate the actual use. The human torso and limbs are approximately cylindrical, so cylindrical tests at the fabric level can be performed to simulate the direct contact between the fabric and the human body or the presence of an air layer. In ordinary bench tests, the horizontal air layer is simulated, i.e., the air layer is parallel to the ground. This experimental method cannot reflect the influence of gravity on air flow.

[0004] When in a fire environment, few people will remain stationary, and firefighters and others are in a state of motion. Due to the displacement between the clothing and the skin during movement and the influence of part of the environmental wind, the air in the air layer under the clothing will no longer remain stationary, but will produce different degrees of undergarment airflow. The flow rate of the undergarment airflow can be calculated from the environmental wind speed, the movement amplitude, and the like. Ordinary bench tests can only simulate the air layer in a stationary state, but cannot simulate the flow of undergarment airflow, i.e., the heat exchange between the local space under the clothing and the surrounding hot or cold air. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an undergarment airflow fabric thermal protective performance evaluation device that can accurately predict the thermal protective performance of a local garment when a dressed human body is in motion.

[0006] The technical solution adopted by the present application to solve the technical problem is: an undergarment airflow fabric thermal protective performance evaluation device, comprising a heat source control system, a cylindrical skin simulator, and an undergarment airflow monitoring system, wherein:

[0007] The heat source control system comprises heat source support one and heat source support two connected by connecting rods, and a heat source control console; a heat source fixing plate is fixed on the heat source support one, a radiation heat source is installed on the heat source fixing plate, and the radiation heat source is electrically connected with the heat source control console; a heat source pre-shielding plate is fixed on the heat source support two, and a shielding plate clamping groove is provided on the heat source support two, and the heat source pre-shielding plate is embedded in the shielding plate clamping groove;

[0008] The upper end of the cylindrical skin simulator is provided with uniformly distributed fabric clamping devices, the fabric clamping devices are provided with sliding rails, the sliding rails are fixed with the cylindrical skin simulator, the surface of the cylindrical skin simulator is embedded with skin simulation sensors, the skin simulation sensors are electrically connected with the data acquisition and processing system, and the surface of the cylindrical skin simulator is provided with a fabric warp heat shrinkage scale.

[0009] The undergarment air flow monitoring system comprises a hot-wire anemometer and a T-shaped thermocouple fixed on the cylindrical skin simulator and electrically connected with the data acquisition and processing system.

[0010] Further, the undergarment air flow simulation device comprises a temperature and speed adjusting fan, a pressure adjusting switch and a temperature adjusting switch are arranged on the temperature and speed adjusting fan, and the undergarment air flow simulation device is connected with a hose for conveying air flow to the undergarment space.

[0011] Further, the cylindrical air layer control support with different diameters is sleeved on the periphery of the cylindrical skin simulator.

[0012] Further, the heat source pre-shielding plate is provided with a shielding plate handle.

[0013] Further, the sliding rail is provided with a scale.

[0014] Further, three skin simulation sensors are arranged on the axis of the cylindrical skin simulator facing and away from the radiant heat source.

[0015] Advantages

[0016] The present application can control the thickness of the air layer under the undergarment through the sliding rail, convey air flow with different temperatures to the undergarment space, and make the heat exchange under the undergarment closer to the state of the human body during movement. According to the different step speeds of the human body, the flow rate of the air flow under the undergarment is calculated, the speed and temperature of the fan are adjusted, and experiments are carried out. The air layer simulation of the device is more in line with the actual situation of the dressed human body. At the same time, the flame-retardant fabric will shrink due to heating during heat exposure. The existing device cannot simulate this phenomenon. The device can simulate the heat shrinkage of the fabric along the warp direction by setting the lower boundary of the fabric to freely sag. The present application can realize the prediction of the overall thermal protection performance of the flame-retardant clothing of the human body during movement in the fire scene, improve the accuracy of the prediction of the overall thermal protection performance, and reduce the cost of the prediction of the overall thermal protection performance. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the present application;

[0018] Figure 2 is a schematic diagram of the cylindrical skin simulator of the present application;

[0019] Figure 3 is a schematic diagram of the air layer control support of the present application;

[0020] In the figure: heat source control system 1, heat source support 1 2, heat source fixing plate 3, radiant heat source 4, heat source pre-shielding plate 5, shielding plate clamping groove 6, shielding plate handle 7, heat source control console 8, cylindrical skin simulator 9, skin simulation sensor 10, fabric clamping device 11, sliding rail 12, fabric sample 13, undergarment air flow monitoring system 14, hot-wire anemometer 15, T-type thermocouple 16, data acquisition and processing system 17, high-temperature-resistant hose 18, undergarment air flow simulation device 19, pressure regulating switch 20, temperature regulating switch 21, temperature and speed regulating fan 22, air layer control support 23, fabric warp heat shrinkage scale 24, heat source support 2 25. DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0022] Flame-retardant fabrics are commonly used in thermal protective clothing such as fire-fighting clothing, and thermal protective clothing is a necessary protective barrier for special operating personnel, so it is of great significance to evaluate the thermal protective performance of thermal protective clothing. Since the thermal exposure test of the fabric has a destructive effect, the thermal exposure experiment of the whole garment is more costly and has limited environmental simulation, so it is of practical significance to accurately predict the thermal protective performance of the whole garment and the burn situation of the human body in the actual wearing state only by testing the thermal protective performance of the flame-retardant fabric.

[0023] The present embodiment provides a device for evaluating the thermal protective performance of undergarment air flow fabric, which simulates the human calf with a cylindrical skin simulator, can consider the longitudinal air layer situation of the actual dressed human body, simulate the airflow situation in the local undergarment space of the human body when the human body moves, i.e. the airflow situation in the fabric air layer system, and can control the distance between the radiant heat source and the fabric and the air layer thickness between the fabric and the sensor, and simulate the shrinkage degree of the fabric along the warp direction, so that the test results are closer to the actual situation, and the accurate prediction of the overall thermal protective performance of the garment is realized.

[0024] The heat source fixing plate is installed on the heat source support 1, and the radiant heat source is arranged on the heat source fixing plate, so that the radiant heat flux density can be adjusted through the heat source control console. The heat source pre-shielding plate is fixed with the heat source support 2 and located between the radiant heat source and the cylindrical skin simulator. The handle is arranged on the heat source pre-shielding plate and can be manually pulled out at the beginning of the test. The radiant heat source adopts a quartz tube which can generate radiant heat with different heat flux densities to simulate various fire environments in which oil chemical industry workers or firefighters are trapped.

[0025] The cylindrical skin simulator is used to simulate the cylindrical shape of the human lower leg, with 6 evenly distributed fabric clamping devices at the upper end, and a sliding rail on the fabric clamping device, which is fixed to the cylindrical skin simulator. A screw is provided on the sliding rail, which is loosened when the fabric clamping device is in a movable state. When the fabric sample is fixed on the fabric clamping device, the sliding rail position can be adjusted to the specified scale, and the screw is tightened to simulate the different air layer thickness between the garment and the human skin. Another air layer control bracket with different diameters is provided, which is sleeved on the outer periphery of the cylindrical skin simulator to ensure the stability of the naturally drooping cylindrical fabric. The naturally drooping fabric will shrink during heat exposure, which can be measured according to the warp heat shrinkage scale.

[0026] The undergarment air flow simulation system is used to generate different flow rates and temperatures of undergarment air flow, which is composed of temperature and speed regulating fan and high temperature resistant hose. The temperature and speed regulating fan can adjust the air speed and temperature by adjusting the voltage and resistance. The high temperature resistant hose can deliver the air flow generated by the fan to the undergarment space. The air flow parameters delivered to the undergarment space are monitored by the undergarment air flow monitoring system. The hot wire anemometer and T-type thermocouple are connected with the data acquisition and processing system, which can realize real-time monitoring of air speed and temperature.

[0027] During exercise, different parts of the body will produce different air flow rates due to the change of undergarment space volume. Before testing, the flow rate of undergarment air flow needs to be calculated according to the simulated part, air layer thickness, air layer volume and calculation. The undergarment air flow through the garment opening (air exchange between closed air layer and environment) can be approximated by the internal air speed and closed air layer thickness. The amplitude and pace of human movement will affect the air flow rate in the closed air layer by affecting the fabric sample radius change rate and the human body trunk system radius change rate.

[0028] The working process includes the following steps:

[0029] Step 1: Prepare a cylindrical fabric sample according to the required air layer thickness on the outer periphery of the cylindrical skin simulator;

[0030] Step 2: Calculate the undergarment air flow rate according to the required air layer thickness using formulas (1)-(2)

[0031] The calculation method of the average air speed v in the closed air layer is as formula (1):

[0032]

[0033] Where, r f is the radius of the fabric sample (m), r b is the radius of the body / cylinder part (m), and l is the height of the body part (m).

[0034] V exc = v.T.p (2)

[0035] where V exc is the air exchange through the clothing opening (m 3 / s), v is the average air velocity in the enclosed air layer (m / s), T is the thickness of the enclosed air layer (m), and p is the perimeter of the enclosed part of the body (m);

[0036] Step 3: Fix the heat source pre-shield plate 5 on the shield plate card slot 6, open the heat source control console 8 and wait for the radiant heat source to stabilize to the experimental value;

[0037] Step 4: Adjust the fabric clamping device 11 and the slide rail 12 to the fixed scale to obtain the required air layer thickness. According to the set air layer thickness, select the appropriate air layer control bracket 23, which is sleeved on the outer periphery of the cylindrical skin simulator, and fix the fabric sample 13 sewn into a cylindrical shape in step 1 on the fabric clamping device 11.

[0038] Step 5: Adjust the temperature and speed of the fan 22 switch to make the output meet the air flow rate obtained in step 2.

[0039] Step 6: Extract the heat source pre-shield plate 5 and start the formal heat exposure experiment. Record the temperature and heat flux density data reaching the skin by the simulated skin sensor 10, measure the heat shrinkage of the fabric along the warp direction according to the fabric warp heat shrinkage scale 24, and record the data by using the data acquisition and processing system 17.

[0040] Step 7: End the experiment after reaching the preset time, calculate the heat transfer inside the skin by using the collected data, and judge whether the burn and the burn grade are reached by using the burn prediction model.

[0041] After the end of a single experiment, wait for the device and sensor to cool down, and start the next round of experiment from step 1. When continuously testing the heat protection performance under the same heat flux density, the heat source correction process in step 3 can not be repeated.

[0042] The present application can control the thickness of the fabric sample and the air layer under the clothes through the sliding rail, and the air flow with different flow rates and temperatures is delivered to the space under the clothes, so that the space under the clothes is closer to the state of the human body during movement. The vertically arranged experimental device can better quantify the warp heat shrinkage of the fabric when the human body is upright, and characterize the thermal aging of the fabric. Different flow rates and temperatures of the fan correspond to the heat exchange process of the space under the clothes of the human body under different external environments and different movement amplitudes. During the test, the air flow under the clothes is accurately controlled, the overall thermal protection performance of the flame-retardant clothing in the movement state can be predicted, the accuracy of the local thermal protection performance prediction is improved, and the cost of the overall thermal protection performance prediction of the clothing is reduced. It has important significance for accurately predicting the burn of the human body.

Claims

1. A device for evaluating the thermal protection performance of under-clothing airflow fabrics, comprising a heat source control system (1), a cylindrical skin simulator (9), and an under-clothing airflow monitoring system (14), characterized in that: The heat source control system includes a heat source bracket 1 (2) and a heat source bracket 2 (25) connected by connecting rods, and a heat source control console (8); a heat source fixing plate (3) is fixed on the heat source bracket 1 (2), a radiant heat source (4) is installed on the heat source fixing plate, and the radiant heat source (4) and the heat source control console (8) are electrically connected; a heat source pre-shielding plate (5) is fixed on the heat source bracket 2 (25), and a shielding plate slot (6) is provided on the heat source bracket 2 (25), and the heat source pre-shielding plate (5) is embedded in the shielding plate slot (6); The cylindrical skin simulator is provided with uniformly distributed fabric clamping devices (11) at the upper end. The fabric clamping devices are provided with slide rails (12). The slide rails are fixed to the cylindrical skin simulator. The surface of the cylindrical skin simulator is embedded with skin simulation sensors (10). The skin simulation sensors are electrically connected to the data acquisition and processing system (17). The surface of the cylindrical skin simulator is provided with a fabric warp heat shrinkage scale (24). The under-clothing airflow monitoring system includes a hot-wire wind speed sensor (15) and a T-type thermocouple (16) fixed on a cylindrical skin simulator (9) and electrically connected to a data acquisition and processing system (17).

2. The device for evaluating the thermal protection performance of under-clothing airflow fabrics according to claim 1, characterized in that, It also includes an airflow simulation device under clothing (19), which includes a temperature- and speed-regulating fan (22), a pressure-regulating switch (20) and a temperature-regulating switch (21) on the fan, and a connecting hose (18) to deliver airflow to the space under clothing.

3. The device for evaluating the thermal protection performance of under-clothing airflow fabrics according to claim 1, characterized in that, It also includes cylindrical air layer control brackets (23) with different diameters, which are fitted around the cylindrical skin simulator.

4. The device for evaluating the thermal protection performance of under-clothing airflow fabrics according to claim 1, characterized in that, The heat source pre-shielding plate is equipped with a shielding plate handle (7).

5. The device for evaluating the thermal protection performance of under-clothing airflow fabrics according to claim 1, characterized in that, The slide rail is marked with graduations.

6. The device for evaluating the thermal protection performance of under-clothing airflow fabrics according to claim 1, characterized in that, The cylindrical skin simulator (9) has three skin simulation sensors (10) on the axis facing away from the radiant heat source and on the axis away from the radiant heat source.

Images