阅读说明：本技术 一种可燃气体吹熄极限测试装置 (combustible gas blows out limit testing arrangement ) 是由 涂然 曾怡 周学进 杜建华 杨凯 姜羲 于 2019-07-08 设计创作，主要内容包括：本发明提供一种可燃气体吹熄极限测试装置,首先包含一个气流发生系统,该系统主要由进气箱、加热段模块、测试箱及风机动力箱组成,用于营造可变风速的平行风场气流；其次包含一个预混气火焰发生系统,主要囊括了高压高纯度燃气气瓶、高压空气气瓶、各个气路与流量计、以及燃烧器等；通过改变平行风场的气流的预热温度、流速,并配合不同预混气组份比例、流量等参量的组合调节,可系统研究强气流对可燃气体火焰形态及吹熄极限的作用规律。(the invention provides a combustible gas blow-out limit testing device, which comprises an airflow generation system, wherein the system mainly comprises an air inlet box, a heating section module, a testing box and a fan power box and is used for creating parallel wind field airflow with variable wind speed; secondly, a premixed gas flame generating system is included, which mainly comprises a high-pressure high-purity gas cylinder, a high-pressure air cylinder, each gas path, a flowmeter, a combustor and the like; by changing the preheating temperature and the flow velocity of the airflow of the parallel wind field and matching with the combined regulation of parameters such as component proportion, flow and the like of different premixed gases, the action rule of strong airflow on the flame shape and the blow-out limit of the combustible gas can be systematically researched.)

1. The utility model provides a combustible gas blows out limit testing arrangement which characterized in that includes: an airflow generating system and a premixed gas flame generating system;

the airflow generating system comprises an air inlet box with a square cross section, and a plurality of rectifying plates are welded at one end of the air inlet box where airflow flows in; the airflow outflow end of the air inlet box is connected with a heating section module with a square cross section;

the inner wall of the heating section module is provided with an electric heating belt, the electric heating belt is formed by arranging a plurality of electric heating wires, has adjustable power and is used for preheating the inflowing air flow so as to enable the air flow to reach a preset initial temperature;

A testing box is connected behind the heating section module, the middle part of the testing box is a cuboid cylinder, and the two end parts of the testing box are gradually reduced and are used for being in sealing connection with other parts;

A rectangular opening is formed in one vertical wall surface of the middle part of the test box, an observation window is hinged above the rectangular opening through two observation windows, and the size of each observation window is larger than that of the rectangular opening;

The rear end of the test box is connected with a fan power box, a high-power variable frequency fan is installed in the fan power box, the rear end of the fan power box is an airflow outlet, two supports are respectively welded at the bottoms of the test box and the fan power box and are arranged on the ground, and the whole airflow generation system is kept horizontal;

the premixed gas flame generating system comprises a high-pressure high-purity gas cylinder and a high-pressure air cylinder; the high-pressure high-purity gas cylinder is sequentially connected in series with a gas valve and a gas flowmeter through a gas circuit; the high-pressure air cylinder is sequentially connected in series with an air valve and an air flow meter through an air gas circuit; the rear end of the gas path is connected with the rear end of the air path, is connected with a gas mixer, is connected with a premixed gas flowmeter in series through a premixed gas path and is connected with the bottom of the combustor;

The burner comprises a burner outer wall, and the center of the bottom of the burner outer wall is perforated and welded with a guide pipe; the guide pipe penetrates through and is fixed in the center of the bottom of the test box and is used for being connected with the premixed gas circuit; a guide cylinder consisting of a plurality of conical cylinders is distributed inside the outer wall of the combustor and is fixed on the outer wall of the combustor in a welding way through a guide cylinder bracket;

in the test box, a thermocouple and an anemoscope are respectively arranged on the upstream of the air path of the combustor, an electric spark igniter capable of performing remote control discharge is arranged on the downstream of the air path of the combustor at the port of the combustor, and a high-speed camera is erected at a position opposite to the observation window for shooting a flame image.

2. a combustible gas blowout limit test apparatus according to claim 1, wherein: the rectifying plates are uniformly arrayed in the air inlet box according to a certain vertical distance.

3. A combustible gas blowout limit test apparatus according to claim 1, wherein: the heating section modules adopt one or more serial modes according to different air flow preheating temperatures.

4. a combustible gas blowout limit test apparatus according to claim 1, wherein: the upper combustion port section of the combustor is designed into various shapes according to different conditions.

5. A combustible gas blowout limit test apparatus according to claim 1, wherein: the section of the upper combustion port of the combustor is circular, square, rectangular or triangular.

6. A combustible gas blowout limit test apparatus according to claim 1, wherein: the thermocouple and the anemometer are installed at positions that avoid the flow path of the air flow of the burner.

7. A combustible gas blowout limit test apparatus according to claim 1, wherein: signals of the thermocouple, the anemoscope and the high-speed camera are all connected into a data acquisition card, and online data acquisition and monitoring are carried out through computer software.

Technical Field

the invention relates to the fields of combustible gas combustion, fire hazard characteristics and the like under the action of a wind field, in particular to a combustible gas blowout limit testing device.

Background

blow-out limit is an important parameter in combustion dynamics and can be used to characterize the stability of the flame under the action of external or internal gas flows. Furthermore, the blow-out limit of the flame under the action of external transverse airflow (or shear flow field) is one of important issues in fire and combustion research, and is helpful for relevant research such as combustible gas combustion performance analysis, combustor stability design and thermal hazard analysis.

heretofore, researchers have carried out certain research in the field of the limit of the blowing out of combustible gas, for example, in the third chapter of the article "research on the morphological characteristics and the promotion and blowing out behavior of the diffusion jet flame under different environmental conditions" (doctor's academic paper of the university of science and technology in China, the author: Wangqiang, the year: 2015), a testing device for the blowing out of combustible gas diffusion flame under the action of side wind is proposed, and the testing device is used for researching the combustion behavior change of single-component combustible gas (propane is selected in the article) under the action of environmental wind. However, such a test device also has some limitations for a thorough study of the blow-out characteristics of combustible gases: firstly, the combustible gas is a single-component gas and can only be used for carrying out a blow-out test of diffusion combustion; secondly, the transverse airflow can only adjust the wind speed and cannot adjust the temperature parameter of the airflow; meanwhile, the burner is single in form and cannot completely reflect the complex conditions in reality, so that the existing testing method cannot meet the deep discussion of the blowing-out limit of the combustible gas.

disclosure of Invention

The invention aims to provide a combustible gas blow-out limit testing device which is used for accurately and quickly proportioning premixed combustible gas and researching the blow-out characteristics of combustible gas flame under the action of transverse parallel wind fields at various concentrations and flows.

In order to solve the above technical problem, the present invention provides a combustible gas blowout limit testing apparatus, including: an airflow generating system and a premixed gas flame generating system;

The airflow generating system comprises an air inlet box with a square cross section, and a plurality of rectifying plates are welded at one end of the air inlet box where airflow flows in; the airflow outflow end of the air inlet box is connected with a heating section module with a square cross section;

The inner wall of the heating section module is provided with an electric heating belt, the electric heating belt is formed by arranging a plurality of electric heating wires, has adjustable power and is used for preheating the inflowing air flow so as to enable the air flow to reach a preset initial temperature;

A testing box is connected behind the heating section module, the middle part of the testing box is a cuboid cylinder, and the two end parts of the testing box are gradually reduced and are used for being in sealing connection with other parts;

A rectangular opening is formed in one vertical wall surface of the middle part of the test box, an observation window is hinged above the rectangular opening through two observation windows, and the size of each observation window is larger than that of the rectangular opening;

The rear end of the test box is connected with a fan power box, a high-power variable frequency fan is installed in the fan power box, the rear end of the fan power box is an airflow outlet, two supports are respectively welded at the bottoms of the test box and the fan power box and are arranged on the ground, and the whole airflow generation system is kept horizontal;

the premixed gas flame generating system comprises a high-pressure high-purity gas cylinder and a high-pressure air cylinder; the high-pressure high-purity gas cylinder is sequentially connected in series with a gas valve and a gas flowmeter through a gas circuit; the high-pressure air cylinder is sequentially connected in series with an air valve and an air flow meter through an air gas circuit; the rear end of the gas path is connected with the rear end of the air path, is connected with a gas mixer, is connected with a premixed gas flowmeter in series through a premixed gas path and is connected with the bottom of the combustor;

The burner comprises a burner outer wall, and the center of the bottom of the burner outer wall is perforated and welded with a guide pipe; the guide pipe penetrates through and is fixed in the center of the bottom of the test box and is used for being connected with the premixed gas circuit; a guide cylinder consisting of a plurality of conical cylinders is distributed inside the outer wall of the combustor and is fixed on the outer wall of the combustor in a welding way through a guide cylinder bracket;

in the test box, a thermocouple and an anemoscope are respectively arranged on the upstream of the air path of the combustor, an electric spark igniter capable of performing remote control discharge is arranged on the downstream of the air path of the combustor at the port of the combustor, and a high-speed camera is erected at a position opposite to the observation window for shooting a flame image.

In a preferred embodiment: the rectifying plates are uniformly arrayed in the air inlet box according to a certain vertical distance.

In a preferred embodiment: the heating section modules adopt one or more serial modes according to different air flow preheating temperatures.

In a preferred embodiment: the upper combustion port section of the combustor is designed into various shapes according to different conditions.

in a preferred embodiment: the section of the upper combustion port of the combustor is circular, square, rectangular or triangular.

In a preferred embodiment: the thermocouple and the anemometer are installed at positions that avoid the flow path of the air flow of the burner.

In a preferred embodiment: signals of the thermocouple, the anemoscope and the high-speed camera are all connected into a data acquisition card, and online data acquisition and monitoring are carried out through computer software.

compared with the prior art, the device has the following technical advantages:

1. The invention provides a combustible gas blowout limit testing device, wherein a rectifying plate of an air inlet box can enable the entering air flow to be as stable and uniform as possible, and the accurate variable air flow velocity and flow field can be created for the testing box through the frequency conversion adjustment of a fan and the real-time data feedback of an anemoscope.

2. the invention provides a combustible gas blow-out limit testing device, wherein the size and the outlet section shape of a burner can be flexibly customized, so that the blow-out limit of combustible gas flame under different working conditions can be researched.

3. The invention provides a combustible gas blow-out limit testing device, wherein due to the combined use of each flowmeter and a gas mixer, the proportioning process of combustible premixed gas can be accurate and quick; at the same time, if the high pressure air cylinder is not used in the test, a diffusion combustion flame blow-out test of a single (non-premixed) combustible gas can also be performed.

4. The invention provides a combustible gas blowout limit testing device, wherein the heating section module is matched with a thermocouple to realize temperature adjustment of airflow, and is used for further researching the rule of influence of a complex airflow environment on the combustible gas blowout limit.

drawings

FIG. 1 is an overall schematic view of a combustible gas blow-off limit test apparatus;

FIG. 2 is a schematic view of a burner in the test apparatus in a square configuration;

FIG. 3 is a schematic view of a circular configuration of the burner in the test apparatus;

Wherein: 100 is an air inlet box, 101 is a rectifying plate, 102 is a heating section module, 103 is an electric heating belt, 104 is a test box, 105 is an observation window, 106 is an observation window hinge, 107 is a fan power box, 108 is a fan, 109 is a support, 110 is the ground, 111 is air flow, 112 is a burner, 113 is a thermocouple, 114 is an anemometer, 115 is an electric spark igniter, 116 is a premixed gas circuit, 117 is a premixed gas flowmeter, 118 is a gas mixer, 119 is a gas circuit, 120 is a gas flowmeter, 121 is an air circuit, 122 is an air flowmeter, 123 is a gas valve, 124 is a high-pressure high-purity gas cylinder, 125 is an air valve, 126 is a high-pressure air cylinder, and 127 is a high-speed camera;

200 is the outer wall of the square combustor, 201 is a guide shell bracket, and 202 is a guide shell;

300 is a circular burner outer wall.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

as shown in fig. 1, the combustible gas blowout limit testing device firstly comprises an airflow generation system, the system comprises an air inlet box 100, the air inlet box 100 is formed by welding stainless steel plates with the thickness of 3mm, a plurality of rectifying plates with equal distance from top to bottom are welded at one end, where the airflow 111 enters, the cross section of the air inlet box 100 at the inflow end of the airflow 111 is a square with the height of 50cm and the width of 50cm, the cross section of the other end (outflow end) of the air inlet box 100 is the height of 35cm and the width of 35cm, and is then connected with a heating section module 102, the module 102 is also a metal cylinder with a square section, an electric heating belt 103 is arranged on the inner wall of the module, and the electric heating belt 103 is formed by arranging a plurality of electric heating wires and has adjustable power; a test box 104 is connected behind the heating section module 102, the shell of the test box 104 is formed by welding stainless steel plates with the thickness of 5mm, the middle part of the test box 104 is a cuboid cylinder with the height of 60cm, the width of 60cm and the length of 120cm, the two end parts of the test box are gradually reduced, a rectangular opening with the height of 50cm and the length of 110cm is arranged right in front of the middle part of the test box 104, an observation window 105 is arranged through two observation window hinges 106, the observation window 105 is made of refractory glass with the thickness of 8mm, the size of the observation window is slightly larger than that of a square opening right in front of the test box 104, so that the opening of the side wall of the test box 104 is completely covered and closed, and meanwhile, the observation window 105 can be flexibly opened through the hinges 106, so that the internal equipment can be; the rear end of the test box 104 is connected with a fan power box 107, a high-power and variable-frequency fan 108 is installed in the fan power box 107, the high-power and variable-frequency fan 108 and the fan power box are coaxial, the rear end of the fan power box 107 is provided with an outlet for discharging airflow 111, two supports 109 are welded at the bottoms of the test box 104 and the fan power box 107 respectively, the supports are placed on the ground 110, and the whole airflow generation system is kept horizontal. The second main system of the testing device is a premixed gas flame generating system, which comprises a high-pressure high-purity gas cylinder 124, such as a methane gas cylinder with a pressure of 10Mpa, which is connected with a gas circuit 119 and is sequentially connected in series with a gas valve 123 and a gas flowmeter 120, similarly, a high-pressure air cylinder 126 is connected with an air gas circuit 121 and is sequentially connected in series with an air valve 125 and an air flowmeter 122, the rear end of the gas circuit 119 is connected into the rear end of the air gas circuit 121 by welding and is connected into a gas mixer 118, so that the two gases are fully premixed, then the two gases are connected into the bottom of a stainless steel burner 112 by a premixed gas circuit 116 and is connected in series with a premixed gas flowmeter 117, the bottom of the burner 112 is cylindrical and just penetrates through and is fixed in the center of the bottom of the testing box 104, while the upper portion of the burner 112 may be shaped and sized as desired, as will be further described below in conjunction with fig. 2 and 3. In addition, a thermocouple 113 and an anemometer 114 are installed in the test box 104 in the left and right oblique directions of the upstream of the air path of the burner 112, respectively, an electric spark igniter 115 is installed at the burner port, the igniter 115 can perform remote control high-voltage electric spark discharge, and a high-speed camera 127 is installed at a position facing the observation window 105 at a certain distance.

As shown in fig. 2, the present embodiment shows a structure of a square burner 112, which includes a square burner outer wall 200 made of stainless steel, the upper portion of the outer wall 200 is a box-shaped structure with a square cross section, for example, 10cm long, 10cm wide, and 5cm high at the inner wall, a hole is drilled and a metal conduit is welded at the center of the bottom portion for connecting the premixed gas path 116, a guide cylinder 202 made of a plurality of similar conical cylinders is arranged inside the outer wall 200, and is welded and fixed in the outer wall 200 through a guide cylinder bracket 201.

as shown in fig. 3, this embodiment also shows another circular burner 112 structure, in which the outer wall of the burner is replaced by a circular outer wall 300, and the shape and size of the burner 112 can be flexibly designed according to the actual test requirements, and the square and circular structures are not limited in this embodiment.

During testing, the flow rate of premixed gas and the temperature of the gas flow 111 are preset in the first step, for example, the initial temperature of the gas flow 111 is determined to be 50 degrees celsius, the gas flow rate of the gas flow meter 120 is preset to be 10 liters per minute, and the flow rate of the air flow meter 122 is preset to be 20 liters per minute; secondly, starting the thermocouple 113, the anemometer 114 and the high-speed camera 127 to start measurement in advance; thirdly, opening the gas valve 123 and the air valve 125, premixing the gas according to a preset flow and proportion, and simultaneously starting the electric spark igniter 115 until the premixed gas in the combustor 112 is ignited and then closing the igniter 115; fourthly, turning on the fan 108 and the electric heating belt 103, increasing the power of the fan 108 and the electric heating belt 103 step by step, and keeping the temperature of the air flow 111 in the test box 104 at 50 ℃ (a disturbance error within 10% is allowed) by matching with the measurement of the thermocouple 113; and fifthly, continuing to slowly increase the power of the fan 108 (meanwhile, increasing the power of the electric heating belt 103 to maintain the preset temperature value of the air flow 111, in the process, performing adjustment on the power of the electric heating belt 103 by taking the reading of the thermocouple 113 more in real time), when the air flow 111 in the test box 104 is increased to a critical value, the flame on the combustor 112 is blown out, and at the moment, the test can be stopped, and relevant temperature, speed and image data are kept for analysis.

and then, the change rule of the blowing-out limit of the strong airflow to the flame of the combustible gas can be further researched through the combination of parameters such as different premixed airflow ratios, airflow preheating temperatures and the like.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby. Equivalent changes and modifications made according to the patent scope and the specification of the present invention should be covered by the present invention.