阅读说明：本技术 一种测定泄漏喷射火撞击钢板表面传热特性的装置及方法 (Device and method for measuring heat transfer characteristics of surface of steel plate impacted by leaked jet fire ) 是由 蒋军成 *** 尤飞 周魁斌 张乐 聂璇 吴月琼 倪磊 于 2020-05-13 设计创作，主要内容包括：本发明涉及一种测定泄漏喷射火撞击钢板表面传热特性的装置,包括钢板支撑装置、喷射火模拟装置、测量装置和燃气安全检测装置；钢板支撑装置包括铝合金框架和钢板,喷射火模拟装置包括实验气瓶、减压阀、金属软管、不锈钢管、气体质量流量控制器、阻火器、燃烧器和点火器,测量装置为若干热电偶、红外热成像仪和热流传感器,燃气安全检测装置为可燃气体检测报警器。优点：系统研究燃气管道泄漏诱发喷射火撞击钢板的传热特性,以及喷射火火焰壁面碰撞时温度和热流的分布规律,为射流火焰撞击传热的深入研究提供更为准确可信的数据支持和理论基础。(The invention relates to a device for measuring the heat transfer characteristic of a leaked jet fire impacting steel plate surface, which comprises a steel plate supporting device, a jet fire simulating device, a measuring device and a fuel gas safety detection device, wherein the steel plate supporting device is provided with a plurality of through holes; the steel plate supporting device comprises an aluminum alloy frame and a steel plate, the injection fire simulation device comprises an experiment gas cylinder, a pressure reducing valve, a metal hose, a stainless steel pipe, a gas mass flow controller, a flame arrester, a burner and an igniter, the measuring device comprises a plurality of thermocouples, an infrared thermal imager and a heat flow sensor, and the gas safety detection device is a combustible gas detection alarm. The advantages are that: the system researches the heat transfer characteristic of the jet fire impacting the steel plate induced by the leakage of the gas pipeline and the distribution rule of temperature and heat flow when the flame wall surface of the jet fire collides, and provides more accurate and credible data support and theoretical basis for the deep research of the jet fire impacting heat transfer.)

1. A device for measuring the heat transfer characteristic of the surface of a steel plate impacted by leaked jet fire is characterized by comprising a steel plate supporting device, a jet fire simulating device, a measuring device and a fuel gas safety detection device; the steel plate supporting device comprises an aluminum alloy frame and a steel plate, the steel plate is rotatably arranged on the aluminum alloy frame, and sensor measuring holes are arranged on the surface of the steel plate along the horizontal axis and the vertical axis; the device comprises a gas cylinder, a pressure reducing valve, a metal hose, a stainless steel pipe, a gas mass flow controller, a flame arrester, a burner and an igniter, wherein the gas cylinder is connected with the pressure reducing valve; the measuring device comprises a plurality of thermocouples, an infrared thermal imager and a heat flow sensor, the surface of the steel plate is provided with the plurality of thermocouples, and the infrared thermal imager and the heat flow sensor are arranged behind the steel plate; the gas safety detection device is a combustible gas detection alarm and is arranged at an experimental gas cylinder, a burner and each pipeline joint.

2. The device for measuring the heat transfer property of a leaked jet fire impacting a steel plate according to claim 1, wherein the steel plate supporting device comprises an aluminum alloy frame, a steel plate, ceramic fiber cotton and a plugging body, the size of the steel plate is 1m × 1m × 0.005.005 m, sensor measuring holes are arranged along the horizontal axis and the vertical axis of the surface of the steel plate, the hole spacing and the diameter are respectively 8cm and 25mm, the bottom frame of the aluminum alloy frame is a hollow rectangular frame with the side length of 1.20 × 1.05m, the vertical support is two parallel hollow rectangular frames with the size of 1.20 × 1.05.05 m, the aluminum alloy frame is connected through an aluminum alloy rod with the length of 15cm, then the vertical support is integrally fastened on the bottom frame through a T-shaped nut and an inner hexagon bolt, a vertical rod of the vertical support is provided with a bulge at the bottom, the bulge can be clamped in a groove of the bottom frame, and can move in the groove to drive the steel plate to freely rotate, so that differentθ(ii) a The whole aluminum alloy frame is wrapped by high-temperature-resistant ceramic fiber cotton, so that the fireproof and heat-insulating effects are achieved.

3. The apparatus of claim 2, wherein the steel plate supporting means further comprises a blocking body, the blocking body is a solid cylinder of the same material as the steel plate, and has a diameter and a thickness of 25mm and 5mm, respectively; when measuring the heat flux of steel sheet surface target position department, the measuring aperture of other positions department is carried out the shutoff with the shutoff body, prevents that the flame from scurrying out and roast peripheral experimental apparatus during the experiment, or causes the danger to personal safety.

4. The device for measuring the heat transfer characteristic of the leaked jet fire impacting the surface of the steel plate as claimed in claim 1, wherein the jet fire simulation device comprises an experimental gas cylinder, a pressure reducing valve, a metal hose, a stainless steel pipe, a gas mass flow controller, a flame arrester, a burner and an igniter, the experimental gas cylinder is made of 30kg standard high-purity canned propane, the pressure reducing valve is connected with the experimental gas cylinder and used for adjusting outlet pressure, the input pressure of the pressure reducing valve is 3Mpa, and the adjusting range is 0-0.16 Mpa; the stainless steel pipe is connected with the pressure reducing valve through a metal hose, the outer diameter of the stainless steel pipe is 16mm, and the wall thickness of the stainless steel pipe is 0.8 mm; the gas mass flow controller is a digital mass flow meter, has a flow range of 0-50SLPM, is arranged at the middle section of the stainless steel pipeline, can quickly and accurately measure the mass flow, the volume flow, the pressure and the temperature of gas in the pipeline, and can adjust the gas flow; the flame arrester is a ferrule type flame arrester for a combustible gas pipeline, has the nominal pressure of 2.5Mpa, is arranged at the tail end of the stainless steel pipeline, and can prevent the externally-sprayed flame from entering the pipeline or prevent the flame in the pipeline from spreading; the combustor is connected with the flame arrester through the metal hose, the igniter is an electronic pulse ignition gun, continuous electric sparks can be generated, the total length is 50cm, and the success rate, the stability and the safety during manual ignition are guaranteed.

5. The apparatus as claimed in claim 4, wherein the burner is made of two sections of k110 steel with equal outer diameter, the total length is 150mm, the section of the front section has a circular, triangular, rectangular or rectangular inner diameter, the length is 30mm, the inner diameter of the rear section is 10mm, the length is 120mm, and the outer thread of the end is convenient for installation and is used for simulating the diameter and the shape of the leakage port of different pipelines.

6. The apparatus of claim 1, wherein said measuring means comprises a type K thermocouple, a type N thermocouple, a type S thermocouple, an infrared thermal imager, and a Gardon type heat flux sensor; according to the propagation characteristic of the jet fire on the surface of the steel plate, 26 thermocouples are arranged at the position 1cm away from the front surface of the steel plate at equal intervals, wherein 7S-type thermocouples, 11N-type thermocouples and 8K-type thermocouples are sequentially arranged along the vertical axis and the horizontal axis of the surface of the steel plate from inside to outside and are fixed by vertical and horizontal supports to form a thermocouple tree, the diameters of the thermocouples are 2mm, the insertion depth of the horizontally arranged thermocouples is 60cm, and the insertion depth of the vertically arranged thermocouples is 55 cm; the measuring range of the infrared thermal imager is-20-650 ℃, and the infrared thermal imager is arranged behind the steel plate; the selected ranges of the Gardon type heat flow sensor are 0-10kW/m respectively²And 0-50kW/m²When measuring the flame heat flow through steel sheet surface measuring hole, the sensor response face keeps flushing with the steel sheet surface, when measuring flame radiation heat flow, should install the sapphire window additional before the sensor response face, when measuring the total heat flow of flame, should demolish the sapphire window before the sensor response face, and heat flow sensor need keep the constant temperature through the water-cooling in whole measurement process.

7. The apparatus according to claim 1, wherein the gas safety monitoring device is a combustible gas detection alarm; a combustible gas detection alarm is arranged below the experimental gas cylinder, the burner and each pipeline joint, the sensor is a semiconductor, the detection concentration is 0-10000ppm, the combustible gas concentration in the surrounding environment can be continuously monitored, and once the combustible gas concentration reaches the alarm preset value, an acoustic/optical alarm is given out.

8. The method for measuring a heat transfer characteristic of a device for measuring a leakage jet fire striking a surface of a steel sheet according to claim 1, comprising the steps of:

1) simulation of pipe leakage ignition to form a jet fire: opening a combustible gas monitoring alarm in advance, then opening a gas cylinder valve and a pressure reducing valve, slowly introducing gas into a pipeline, setting the gas mass flow required by the experiment through a gas mass flow controller, and immediately carrying out continuous manual ignition at a burner nozzle by using an igniter when the reading of the gas mass flow controller is stable until stable jet fire is formed;

if the ignition fails, the set value of the gas mass flow controller returns to zero, the pressure reducing valve and the gas cylinder valve are closed, and the indoor ventilation is carried out;

in addition, the diameters and the shapes of different leakage openings of the gas pipeline can be simulated by replacing the burner;

2) simulation of the impact of the jet fire on the steel plate and the impact angle: vertically placing a steel plate supporting device at a certain distance in front of a nozzle of a combustor, wherein the center of a steel plate is always aligned with the central axis of the nozzle, and ensuring that the jet fire impacts the steel plate by adjusting the distance between the steel plate and the nozzle of the combustor;

in addition, different impact angles of the jet fire can be simulated by rotating the vertical rod;

3) and (3) measuring heat transfer characteristic parameters of the steel plate impacted by the jet fire: by arranging thermocouple trees along the vertical and horizontal axes of the surface of the steel plate according to the requirements, the near-wall reference temperature can be measuredA value of (d); the temperature of the back surface of the flat plate can be measured by arranging the thermal infrared imager at a proper position behind the steel plate according to the requirementsA value of (d); by arranging the heat flow sensor at the target position on the surface of the steel plate according to the requirements, the measurement is respectively carried out under the two conditions of adding and not adding the sapphire windowAnd

Technical Field

The invention discloses a device and a method for measuring the heat transfer characteristic of a steel plate surface impacted by a leakage jet fire, and belongs to the technical field of fire safety.

Background

The gas pipeline is cracked and leaked due to corrosion, stress damage, damage to valves and accessories and the like, and if the leaked gas meets a fire source at the crack, the leaked gas is ignited to form jet fire. The jet fire is a common accident type after the gas pipeline leaks, the flame length of the jet fire is from several meters to tens of meters or even hundreds of meters, and the jet fire releases a large amount of heat, thereby causing great threat to the safety of personnel and property around the pipeline. When the flame of the jet fire directly contacts the surface of equipment or a building, and the influence of heat radiation on adjacent equipment or the building further expands the accident range and aggravates the accident damage degree. For example, in Belgium in 2004, a natural gas pipeline of Ghislenghien leaks and explodes to cause a jet fire, so that nearby vehicles catch fire in the range of about 150-. Therefore, the research on the heat transfer rule between the jet fire generated after the gas pipeline leaks and the surface of the surrounding structural material has great significance for preventing and controlling the jet fire accident hazard of the gas pipeline.

At present, the steel material is still the most main structural material in the industry, and the research on the surface heat transfer process of the existing steel material mostly focuses on the water cooling heat exchange of the surface of the steel material to obtain the ideal performance of the steel material. No report is found about the measurement method and device for the heat transfer characteristic of the jet flame directly impacting the surface of the adjacent steel structural material in the industrial jet fire disaster process. For example, chinese patent CN105445319A discloses a method and apparatus for determining the surface water-cooling heat transfer coefficient of a steel plate, which utilizes finite element simulation calculation to obtain the surface water-cooling heat transfer coefficient of the steel plate under the non-contact condition; chinese patent CN102661969A discloses a test device and a calculation method for testing the heat exchange coefficient of the surface of a steel plate under the condition of different water film thicknesses; chinese patent CN201799458U discloses a device for actually measuring the temperature field of a steel plate by a thermocouple under ultra-fast cooling conditions and calculating the heat exchange coefficient of the steel plate by using the inverse algorithm of the temperature field. Obviously, the current technology for measuring the heat exchange coefficient of the surface of the steel material in the cooling control process cannot be used for measuring the heat transfer mechanism and the heat transfer characteristic of the surface of the steel material under the condition of jet fire impact, and cannot be used for extracting and predicting the distribution characteristics of temperature and heat flow when the flame wall surface of the jet fire collides.

Disclosure of Invention

The invention provides a device and a method for measuring the heat transfer characteristic of a surface of a steel plate impacted by a leakage jet fire, aiming at the problems that the existing measurement of the heat exchange characteristic of the surface of an iron and steel material mostly aims at the cooling control in the production process of the iron and steel material and is not suitable for heat transfer analysis under the action of industrial jet fire hazard, so that a set of experimental device for measuring the heat transfer characteristic of the surface of the steel plate impacted by the leakage jet fire induced by a gas pipeline is specially designed on the basis of the theoretical analysis of jet flame impact heat transfer.

The technical solution of the invention is as follows: a device for measuring the heat transfer characteristic of the surface of a steel plate impacted by leaked jet fire structurally comprises a steel plate supporting device, a jet fire simulating device, a measuring device and a fuel gas safety detection device; the steel plate supporting device comprises an aluminum alloy frame and a steel plate, the steel plate is rotatably arranged on the aluminum alloy frame, and sensor measuring holes are arranged on the surface of the steel plate along the horizontal axis and the vertical axis; the device comprises a gas cylinder, a pressure reducing valve, a metal hose, a stainless steel pipe, a gas mass flow controller, a flame arrester, a burner and an igniter, wherein the gas cylinder is connected with the pressure reducing valve; the measuring device comprises a plurality of thermocouples, an infrared thermal imager and a heat flow sensor, the surface of the steel plate is provided with the plurality of thermocouples, and the infrared thermal imager and the heat flow sensor are arranged behind the steel plate; the gas safety detection device is a combustible gas detection alarm and is arranged at an experimental gas cylinder, a burner and each pipeline joint.

The steel plate supporting device comprises an aluminum alloy frame, a steel plate and ceramic fiber cotton, the size of the steel plate is 1m multiplied by 0.005m, sensor measuring holes are arranged along the horizontal and vertical axes of the surface of the steel plate, and the distance between the holes and the diameter of the holes are 8cm and 25mm respectively; the aluminum alloy frame bottom frame is a hollow rectangular frame with the side length of 1.20 multiplied by 1.05m, the vertical supports are two parallel hollow rectangular frames with the size of 1.20 multiplied by 1.05m, the two parallel hollow rectangular frames are connected through an aluminum alloy rod piece with the length of 15cm, and then the vertical supports are integrally fastened on the bottom frame through T-shaped nuts and inner hexagon bolts; the bottom of one of the vertical rods of the vertical support is provided with a bulge which can be clamped in a groove of the bottom frame, and the bulge can move in the groove and is used for driving the steel plate to rotate freely so as to realize different impact angles theta; the whole aluminum alloy frame is wrapped by high-temperature-resistant ceramic fiber cotton, so that the fireproof and heat-insulating effects are achieved.

The steel plate supporting device also comprises a blocking body, wherein the blocking body is a solid cylinder made of the same material as the steel plate, and the diameter and the thickness of the blocking body are respectively 25mm and 5 mm; when measuring the heat flux of steel sheet surface target position department, the measuring aperture of other positions department is carried out the shutoff with the shutoff body, prevents that the flame from scurrying out and roast peripheral experimental apparatus during the experiment, or causes the danger to personal safety.

The jet fire simulation device comprises an experimental gas cylinder, a pressure reducing valve, a metal hose, a stainless steel pipe, a gas mass flow controller, a flame arrester, a burner and an igniter, wherein the experimental gas cylinder is made of 30kg of standard high-purity canned propane, the pressure reducing valve is connected with the experimental gas cylinder and used for adjusting outlet pressure, the input pressure of the pressure reducing valve is 3MPa, and the adjusting range is 0-0.16 MPa; the stainless steel pipe is connected with the pressure reducing valve through a metal hose, the outer diameter of the stainless steel pipe is 16mm, and the wall thickness of the stainless steel pipe is 0.8 mm; the gas mass flow controller is a digital mass flow meter, has a flow range of 0-50SLPM, is arranged at the middle section of the stainless steel pipeline, can quickly and accurately measure the mass flow, the volume flow, the pressure and the temperature of gas in the pipeline, and can adjust the gas flow; the flame arrester is a ferrule type flame arrester for a combustible gas pipeline, has the nominal pressure of 2.5Mpa, is arranged at the tail end of the stainless steel pipeline, and can prevent the externally-sprayed flame from entering the pipeline or prevent the flame in the pipeline from spreading; the combustor is connected with the flame arrester through the metal hose, the igniter is an electronic pulse ignition gun, continuous electric sparks can be generated, the total length is 50cm, and the success rate, the stability and the safety during manual ignition are guaranteed.

The combustor comprises two sections of equal-outer-diameter k110 steel, the total length is 150mm, the cross section of the inner diameter of the front section is circular, triangular, rectangular or rectangular, the length is 30mm, the inner diameter of the rear section is 10mm, the length is 120mm, and the combustor is convenient to install for the outer threads of the tail end of the combustor and is used for simulating the diameters and the shapes of leakage ports of different pipelines.

The measuring device comprises a K-type thermocouple, an N-type thermocouple, an S-type thermocouple, an infrared thermal imager and a Gardon-type heat flow sensor; according to the propagation characteristic of the jet fire on the surface of the steel plate, 26 thermocouples are arranged at the position 1cm away from the front surface of the steel plate at equal intervals, wherein 7S-type thermocouples, 11N-type thermocouples and 8K-type thermocouples are sequentially arranged along the vertical axis and the horizontal axis of the surface of the steel plate from inside to outside and are fixed by vertical and horizontal supports to form a thermocouple tree, the diameters of the thermocouples are 2mm, the insertion depth of the horizontally arranged thermocouples is 60cm, and the insertion depth of the vertically arranged thermocouples is 55 cm; the measuring range of the infrared thermal imager is-20-650 ℃, and the infrared thermal imager is arranged behind the steel plate; the selected ranges of the Gardon type heat flow sensor are 0-10kW/m respectively²And 0-50kW/m²When measuring the flame heat flow through steel sheet surface measuring hole, the sensor response face keeps flushing with the steel sheet surface, when measuring flame radiation heat flow, should install the sapphire window additional before the sensor response face, when measuring the total heat flow of flame, should demolish the sapphire window before the sensor response face, and heat flow sensor need keep the constant temperature through the water-cooling in whole measurement process.

The gas safety monitoring device is a combustible gas detection alarm; a combustible gas detection alarm is arranged below the experimental gas cylinder, the burner and each pipeline joint, the sensor is a semiconductor, the detection concentration is 0-10000ppm, the combustible gas concentration in the surrounding environment can be continuously monitored, and once the combustible gas concentration reaches the alarm preset value, an acoustic/optical alarm is given out.

The determination method comprises the following steps:

1) simulation of pipe leakage ignition to form a jet fire: the combustible gas monitoring alarm is opened in advance, then a gas cylinder valve and a pressure reducing valve are opened, gas is slowly introduced into a pipeline, the mass flow of gas required by an experiment is set through a gas mass flow controller, and when the reading of the gas mass flow controller is stable, continuous manual ignition is immediately carried out at a burner nozzle by an igniter until stable jet fire is formed. If the ignition fails, the set value of the gas mass flow controller returns to zero, the pressure reducing valve and the gas cylinder valve are closed, and the indoor ventilation is carried out. In addition, the diameters and the shapes of different leakage openings of the gas pipeline can be simulated by replacing the burner;

2) simulation of the impact of the jet fire on the steel plate and the impact angle: place steel sheet strutting arrangement certain distance department before the combustor spout perpendicularly, the spout axis is aligned all the time at the steel sheet center, through adjusting the distance between steel sheet and the combustor spout, guarantees to spray the fire and strikes the steel sheet. In addition, different impact angles of the jet fire can be simulated by rotating the vertical rod;

3) and (3) measuring heat transfer characteristic parameters of the steel plate impacted by the jet fire: by arranging thermocouple trees along the vertical and horizontal axes of the surface of the steel plate according to the requirements, the near-wall reference temperature T can be measured_refA value of (d); the temperature T of the back surface of the flat plate can be measured by arranging the thermal infrared imager at a proper position behind the steel plate according to the requirements_bA value of (d); by arranging the heat flow sensor at the target position on the surface of the steel plate according to the requirements, the measurement is respectively carried out under the two conditions of adding and not adding the sapphire windowAnd

finally obtaining the heat transfer characteristic parameter h of the steel plate impacted by the jet fire through calculation_fj。

The invention has the beneficial effects that:

1) the existing device is mainly used for the water cooling process of a steel plate, is used for improving the performance of the steel plate, such as physical performance and machining performance, and cannot be applied to the background of industrial injection fire hazard, namely the damage influence of injection fire on adjacent steel structural materials.

2) The device can systematically research the heat transfer characteristic of the jet fire impacting the steel plate induced by the leakage of the gas pipeline and the distribution rule of temperature and heat flow when the flame wall surface of the jet fire collides, and provides more accurate and credible data support and theoretical basis for the deep research of the jet flame impacting heat transfer.

3) Can provide effective suggestions for safety problems related to the arrangement of the surrounding defense and the plane arrangement of the gas pipeline, and has great research and popularization values.

Drawings

FIG. 1 is a schematic illustration of the conservation of energy of a diffusion flame impinging on a flat plate surface.

FIG. 2 is a schematic diagram of a gas pipeline leakage ignition spray fire forming simulation device.

Fig. 3 is a schematic view of the burner structure.

FIG. 4 is a schematic diagram of the thermocouple arrangement on the surface of the steel plate.

Fig. 5 is a schematic diagram of a steel plate surface heat flow sensor arrangement.

Fig. 6 is a general layout (θ ═ 0 °).

Fig. 7 is a structural view of a steel plate supporting device.

In the figure, 1a steel plate supporting device (1a steel plate, 1b aluminum alloy bracket, 1c ceramic fiber cotton, 1d rotatable vertical rod and 1e blocking body), 2 igniters, 3 burners, 4 flame arresters, 5/6 metal hoses, 7 stainless steel pipes, 8 gas mass flow controllers, 9 pressure reducing valves, 10 experimental gas cylinders, 11 thermocouples, 12 infrared thermal imagers, 13 heat flow sensors, 14/15 combustible gas monitoring alarms and 16 experimental data acquisition devices.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

As shown in fig. 1, when the jet flame hits the flat plate, the energy conservation equation of the flat plate surface can be expressed by using the one-dimensional heat conduction assumption:

substituting equations (2) to (6) into equation (1) can derive:

wherein h is_fjIs the convective heat transfer coefficient of jet flame, W/(m)²·K)；h_NCIs the natural convection heat transfer coefficient of air, W/(m)²·K)；T_ref、T_f、T_bAnd T_∞Respectively obtaining a near-wall reference temperature, a front temperature of a flat plate, a back temperature of the flat plate and an ambient air temperature K;_pand_frespectively the emissivity of the plate and the emissivity of the flame covering the surface of the plate, sigma is the Stefan-Boltzmann constant, 5.67 × 10^-8W/(m²·K⁴)。

According to the formula (7), 4 known quantities are involved in the energy conservation equation after finishing, and the quantities are respectively h_NC、_p、T_∞And σ, the remaining 5 are unknowns, i.e. h_fj、T_ref、T_f、T_bAnd_f. In order to reduce the number of unknowns to be solvedAnd to reduce the complexity of the problem itself, while experimentation as a basic means of investigating fluid flow and heat transfer and related problems requires that the values of some unknown quantities be measured as accurately and reliably as possible during the course of the experiment. Wherein, T_refAnd T_bThe thermocouple tree and the infrared thermal imager can be respectively arranged on the near-wall surface and the back surface of the panel to carry out accurate measurement. In addition, by trying to mount the Gardon-type heat flow sensor sensing surface (with a removable sapphire window attachment to shield the effects of convection) flush with the surface of the plate, further measurements can be madeAnd

value of [1 ]]. Finally, the solution problem of the jet flame impingement plate heat transfer fundamental equation is simplified to a 3-element (h) solution of 3 equations (1), (2) and (7))_fj、T_fAnd_f) The specific solving process of the nonlinear equation system can be realized by a fsolve function in Matlab, and the algorithm adopted by the function is a nonlinear least square method.

As shown in figure 6, based on the theoretical analysis of the jet flame impingement heat transfer, a method and a device for measuring the heat transfer characteristic of the jet fire impinging on the surface of the steel plate, which is induced by the simulated gas pipeline leakage, are designed, and are used for researching the change of the heat transfer rule between the gas pipeline leakage jet fire and the adjacent steel structure in the industrial fire.

The experimental simulation device consists of a steel plate supporting device, a simulation device for forming jet fire by the leaked and ignited gas pipeline, a measuring device and a gas safety detection device.

The steel plate supporting device comprises: the aluminum alloy plug consists of an aluminum alloy frame, a steel plate, ceramic fiber cotton and a plug body. As shown in fig. 7, the size of the steel plate is 1m × 1m × 0.005m, the sensor measuring holes are arranged along the horizontal and vertical axes of the surface of the steel plate, the hole distance and the diameter are 8cm and 25mm respectively, the aluminum alloy frame bottom frame is a hollow rectangular frame with the side length of 1.20 × 1.05m, the vertical support is two parallel hollow rectangular frames (the size is 1.20 × 1.05m), the two parallel hollow rectangular frames are connected through an aluminum alloy rod with the length of 15cm, and then the vertical support is integrally fastened on the bottom frame through a T-shaped nut and an inner hexagon bolt. One of them vertical pole bottom of vertical support has the arch, but the joint is in underframe recess, and the arch can be in the recess internalization for drive steel sheet free rotation realizes different striking angle theta. The whole aluminum alloy frame is wrapped by high-temperature-resistant ceramic fiber cotton, so that the fireproof and heat-insulating effects are achieved. The plugging body is a solid cylinder made of the same material as the steel plate, and the diameter and the thickness of the plugging body are respectively 25mm and 5mm. When the heat flux of the target position on the surface of the steel plate is to be measured, the measuring holes at other positions can be blocked by the blocking bodies, so that the flame is prevented from escaping to bake peripheral experimental instruments or causing danger to the personal safety during the experiment.

The gas pipeline leaks and ignites to form the analogue means that sprays the fire: mainly by experiment gas cylinder, relief pressure valve, metal collapsible tube, stainless steel pipe, gas mass flow controller, spark arrester, combustor and ignition etc. constitute, specific structure is as shown in figure 2. The experimental gas cylinder can adopt 30kg of standard high-purity (99.9%) canned propane. The pressure reducing valve is connected with the gas cylinder and used for adjusting outlet pressure, the input pressure of the pressure reducing valve is 3Mpa, and the adjusting range is 0-0.16 Mpa. The stainless steel pipe is connected with the pressure reducing valve through a metal hose, the outer diameter of the stainless steel pipe is 16mm, and the wall thickness of the stainless steel pipe is 0.8 mm. The gas mass flow controller is a digital mass flow meter, has a flow range of 0-50SLPM, is arranged in the middle section of the stainless steel pipeline, can quickly and accurately measure the mass flow, the volume flow, the pressure and the temperature of gas in the pipeline, and can adjust the gas flow. The flame arrester is a ferrule type flame arrester for a combustible gas pipeline, has nominal pressure of 2.5Mpa, is arranged at the tail end of the stainless steel pipeline, and can prevent external jet flame from entering the pipeline or prevent the flame in the pipeline from spreading. The combustor is connected with the spark arrester through metal collapsible tube, the combustor comprises outer footpath k110 steel such as two sections, and total length is 150mm, and the anterior segment internal diameter is 2mm, 3mm, 4mm respectively, and length is 30mm (also can process into triangle-shaped, rectangle and rectangle etc. with cross sectional shape), and the back end internal diameter is 10mm, and length is 120mm to terminal car external screw thread, the installation of being convenient for, concrete structure is as shown in fig. 3, can be used to simulate different pipeline leakage mouth diameters and shape. The igniter is an electronic pulse igniter gun which can generate continuous electric sparks, the total length is 50cm, and success rate, stability and safety during manual ignition are guaranteed.

A measuring device: including K-, N-, and S-type thermocouples, infrared thermal imagers, and Gardon-type thermal flow sensors. According to the propagation characteristic of the jet fire on the surface of the steel plate, 26 thermocouples are arranged at the position 1cm away from the front surface of the steel plate at equal intervals (5cm), wherein 7S-type thermocouples, 11N-type thermocouples and 8K-type thermocouples are sequentially arranged from inside to outside along the vertical axis and the horizontal axis of the surface of the steel plate and are fixed by vertical and horizontal supports to form a thermocouple tree, the diameters of the thermocouples are 2mm, the insertion depth of the horizontally arranged thermocouples is 60cm, the insertion depth of the vertically arranged thermocouples is 55cm, and the specific arrangement structure is shown in FIG. 4. By adopting the thermocouple tree arrangement mode on the surface of the steel plate, the influence of the thermocouple diameter on the flame propagation on the surface of the steel plate can be reduced, and the (reference) temperature distribution characteristic of the whole steel plate surface can be accurately and completely acquired. An infrared thermal imager (the selected range is-20-650 ℃) is arranged at a proper position behind the steel plate, and the thermal image of the back of the whole steel plate can be clearly obtained through the automatic focusing function. Gardon type heat flow sensor (the selected ranges are 0-10kW/m respectively²And 0-50kW/m²) When measuring the flame heat flow through steel sheet surface measurement hole, the sensor response face will keep flushing (as shown in fig. 5) with the steel sheet surface, when measuring flame radiation heat flow, should install the sapphire window additional before the sensor response face, when measuring the total heat flow of flame, should demolish the sapphire window before the sensor response face, and heat flow sensor need keep the constant temperature through the water-cooling in whole measurement process.

Gas safety monitoring device: the commercial combustible gas detection alarm is arranged below the experimental gas cylinder, the burner and each pipeline joint, the sensor is a semiconductor, the detection concentration is 0-10000ppm, the combustible gas concentration in the surrounding environment can be continuously monitored, and once the alarm preset value is reached, an acoustic/optical alarm can be sent out.

Simulation of pipe leakage ignition to form a jet fire: the combustible gas monitoring alarm is opened in advance, then a gas cylinder valve and a pressure reducing valve are opened, gas is slowly introduced into a pipeline, the mass flow of gas required by an experiment is set through a gas mass flow controller, and when the reading of the gas mass flow controller is stable, continuous manual ignition is immediately carried out at a burner nozzle by an igniter until stable jet fire is formed. If the ignition fails, the set value of the gas mass flow controller returns to zero, the pressure reducing valve and the gas cylinder valve are closed, and the indoor ventilation is carried out. In addition, different leakage opening diameters and shapes of the gas pipeline can be simulated by replacing the burner.

Simulation of the impact of the jet fire on the steel plate and the impact angle: place steel sheet strutting arrangement certain distance department before the combustor spout perpendicularly, the spout axis is aligned all the time at the steel sheet center, through adjusting the distance between steel sheet and the combustor spout, guarantees to spray the fire and strikes the steel sheet. In addition, different impact angles of the jet fire can be simulated by rotating the vertical rod.

And (3) measuring heat transfer characteristic parameters of the steel plate impacted by the jet fire: by arranging the thermocouple trees along the vertical and horizontal axes of the surface of the steel plate according to the requirements, the unknown parameter T can be measured_refA value of (d); the unknown parameter T can be measured by arranging the thermal infrared imager at a proper position behind the steel plate according to the requirements_bA value of (d); by arranging the heat flow sensor at the target position on the surface of the steel plate according to the requirements, the unknown parameters can be respectively measured under the two conditions of adding and not adding the sapphire windowAnd

the value of (c). After the values of four unknown parameters are obtained, a ternary nonlinear equation set is formed through simultaneous formulas (1), (2) and (7), a fsolve function in Matlab is used for solving, and finally, a parameter h of the heat transfer characteristic of the steel plate impacted by the jet fire can be obtained_fj。