A method for measuring temperature distribution and estimating heat release in pool fire combustion in confined spaces

Abstract

The present invention relates to a method for testing the temperature distribution of pool fire combustion in a confined space and estimating heat release. By using the method for testing the temperature distribution of pool fire combustion in a confined space and estimating heat release provided by the present invention, the temperature distribution at different positions in the combustion chamber can be obtained by designing a thermocouple tree, arranging the thermocouple tree according to the requirements of the central fire and the side wall fire in the combustion chamber, and setting temperature measurement points. At the same time, by using the method provided by the present invention, the heat flux density of the fuel solution during combustion in the combustion chamber can be measured using a radiation heat flux density meter and a convection heat flux density meter, and the heat release rate and combustion efficiency of the pool fire combustion in a confined space can be estimated. The present invention provides fire safety technical support for buildings such as factories, equipment rooms, and oil depots.

Description

Technical Field

[0001] The present invention belongs to the technical field of pool fire accident research, and in particular relates to a method for testing the combustion temperature distribution and estimating the heat release of a pool fire in a confined space. Background Art

[0002] Pool fire accidents are one of the typical safety accidents in industrial production processes. The thermal radiation and heat flow generated by fire accidents will directly or indirectly affect safety-related buildings (structures), systems and components, and may even further cause explosion accidents. Therefore, it is crucial to study the distribution of temperature fields and heat release in pool fire accidents. Currently, the temperature field distribution and heat release can be obtained through calculations using some simulation software. However, there is still a certain gap between the temperature field distribution and heat release data obtained by simulation software and the temperature field distribution and heat release data obtained by actual measurements. Of course, the data obtained by actual measurements are more accurate.

[0003] Therefore, in order to facilitate the acquisition of temperature conditions at different locations, the inventors have designed a method for testing the temperature distribution and estimating heat release of pool fire combustion in a confined space. Summary of the Invention

[0004] In response to the defects in the existing technology, the purpose of the present invention is to provide a method for testing the temperature distribution of pool fire combustion in a confined space and estimating the heat release, so as to obtain the temperature conditions at different locations and a method for estimating the heat release of solution combustion, and provide fire safety technical support for buildings such as factories, equipment rooms and oil depots.

[0005] To achieve the above objectives, the present invention adopts a technical solution: a method for testing the combustion temperature distribution and estimating the heat release of a confined space pool fire, comprising the following steps:

[0006] S1. Designing a thermocouple tree: setting up a thermocouple tree formed by bundling multiple thermocouples, and transmitting data signals measured by the thermocouples to a computer for storage;

[0007] S2. Distributing temperature measurement points: Arranging the thermocouple tree and setting temperature measurement points to obtain the temperature distribution in the combustion chamber;

[0008] S3. Measure heat flux density and estimate heat release rate and combustion efficiency.

[0009] Furthermore, the thermocouple tree is suspended in the combustion chamber, and the outside of the thermocouple tree is protected by a stainless steel sleeve, which is fixed to the top of the combustion chamber;

[0010] The temperature compensation wire of the thermocouple passes through the wire hole preset on the top of the combustion chamber;

[0011] The data signal measured by the thermocouple is received by a data acquisition card and transmitted to a computer by the data acquisition card for storage.

[0012] Furthermore, step S2 includes the following steps:

[0013] S21. Arranging the thermocouple tree in the combustion chamber;

[0014] S22, estimate the flame height;

[0015] S23. Setting temperature measurement points: Based on the estimated flame height, ensure that there are three or more temperature measurement points in the flame, and that the temperature measurement points are evenly distributed in the flame;

[0016] S24. Obtain the temperature distribution in the combustion chamber.

[0017] Furthermore, the arrangement method of the thermocouple tree is as follows: according to the requirements of the center fire and / or side wall fire of the combustion chamber, the thermocouple tree is arranged in the combustion chamber with length, width and height dimensions of a, b and c respectively: the thermocouple tree is arranged starting from the center axis of the oil pan, and a thermocouple tree is arranged every 0.5m for the center fire; the side wall fire is arranged every 0.5m within b / 2 of the center axis of the oil pan, and a thermocouple tree is arranged every 1m outside b / 2 of the center axis of the oil pan.

[0018] Furthermore, the flame height is estimated by formula (1):

[0019]

[0020] Where, L is the flame height, m;

[0021] D—equivalent diameter of oil pan, m;

[0022] —dimensionless heat release rate;

[0023] The dimensionless heat release rate According to formula (2), we can get:

[0024]

[0025] in,

[0026] —dimensionless heat release rate;

[0027] —heat release rate, kW;

[0028] ρ ∞ —Ambient air density, 1.2 kg / m 3 ;

[0029] c p —Specific heat capacity of ambient air, 1.0 kJ / (kg·K);

[0030] T ∞ —Ambient air temperature, 293K;

[0031] g—acceleration due to gravity, 9.81 kg·m / s;

[0032] D—equivalent diameter of oil pan, m;

[0033] The heat release rate According to formula (3), we can get:

[0034]

[0035] in,

[0036] —heat release rate, kW;

[0037] x—combustion efficiency, taking the maximum value x=1.0;

[0038] —Solution burning rate, kg / s;

[0039] A f —Oil pan area, m 2 ;

[0040] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0041] ΔH c —Heat of combustion of the solution, MJ / kg.

[0042] Furthermore, when c / 8>0.5m, a temperature measurement point is set at every 0.5m along the height direction of the combustion chamber except the flame area; when c / 8≤0.5m, a temperature measurement point is set at every c / 8 along the height direction of the combustion chamber except the flame area;

[0043] The thermocouples set at the temperature measurement points in the flame are 5mm diameter armored K-type thermocouples with a measuring range of 0 to 1300°C; in closed or semi-sealed spaces, the thermocouples set at the temperature measurement points outside the flame are all 1mm armored K-type thermocouples.

[0044] Furthermore, the temperature distribution at different positions on the axial surface of the combustion chamber is calculated by the point distance inverse interpolation method; or the temperature distribution results in the combustion chamber are directly fitted using the contour module of the Origin curve software.

[0045] Furthermore, the heat flux density measurement method is as follows: two groups of heat flux density sensors are set at the monitoring point, including a first heat flux density sensor and a second heat flux density sensor; and each group of heat flux density sensors includes a radiation heat flux density meter and a convection heat flux density meter, respectively used to measure the radiation heat flux density and the convection heat flux density;

[0046] The first heat flux density sensor is used to monitor the heat flux density in the horizontal direction of the horizontal plane where the flame center is located, and the second heat flux density sensor is used to monitor the heat flux density at a 45° angle to the horizontal plane where the flame center is located;

[0047] The horizontal distance between the monitoring point and the center of the combustion pool flame is adjusted according to the actual oil pan size. As the oil pan increases, the distance increases accordingly to avoid the flame burning the sensor.

[0048] Furthermore, the estimation of the heat release rate refers to respectively calculating the heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located and the heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the heat release rate is calculated according to the following formula (4):

[0049] Q s =Q x +Q r +Q d (4)

[0050] in,

[0051] Q s —Solution combustion heat release rate, J / s;

[0052] Q x —Solution heat absorption rate, J / s;

[0053] Q r —Radiative heat release rate, J / s;

[0054] Q d —Convective heat release rate, J / s;

[0055] The heat absorption rate Q of the solution x It can be calculated according to formula (5):

[0056]

[0057] in,

[0058] Q x —Solution heat absorption rate, kW;

[0059] C p —Specific heat capacity of the burning solution, kJ / (kg·K);

[0060] T f —Flame temperature of the solution surface, °C;

[0061] T l —Temperature of the solution, °C;

[0062] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0063] A f —Oil pan area, m 2 ;

[0064] The radiative heat release rate Q r is the radiation heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located, or the radiation heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the radiation heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located and the radiation heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated according to formula (6):

[0065] Q r =(4πr 2 / t c )h fr (6)

[0066] in,

[0067] Q r —Radiative heat release rate, J / s;

[0068] r—the distance between the monitoring point and the flame center, m;

[0069] t c —Penetration coefficient, select value 1;

[0070] h fr —Radiant heat flux, W·m -2 ;

[0071] The convective heat release rate Q d is the convective heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located, or the convective heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the convective heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located and the convective heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated according to formula (7):

[0072] Q d =(4πr 2 / t c )h fd(7)

[0073] in,

[0074] Q d —Convective heat release rate, J / s;

[0075] r—the distance between the monitoring point and the flame center, m;

[0076] t c —Penetration coefficient, select value 1;

[0077] h fd —Convective heat flux, W·m -2 .

[0078] Furthermore, the combustion efficiency is estimated by: calculating the combustion efficiency of a monitoring point in the horizontal direction of the horizontal plane where the flame center is located and the combustion efficiency of a monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the combustion efficiency of the fuel solution is calculated as the average of the combustion efficiency of the horizontal monitoring point and the combustion efficiency of the monitoring point at an angle of 45°;

[0079] According to formula (8), the combustion efficiency of the monitoring point horizontal to the horizontal plane where the flame center is located and the combustion efficiency of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated respectively:

[0080]

[0081] in,

[0082] η—solution combustion efficiency, J / s;

[0083] Q s —Solution combustion heat release rate, J / s;

[0084] A f —Oil pan area, m 2 ;

[0085] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0086] ΔH c —Heat of combustion of the solution, MJ / kg.

[0087] The beneficial effects of the present invention are as follows: using the temperature distribution testing and heat release estimation method for confined space pool fire combustion provided by the present invention, the temperature distribution at different locations in the combustion chamber can be determined by designing a thermocouple tree, arranging the thermocouple tree according to the requirements of the combustion chamber center fire and side wall fire, and setting temperature measurement points. Furthermore, using the method provided by the present invention, the heat flux density of the fuel solution burning in the combustion chamber can be measured using a radiation heat flux meter and a convection heat flux density meter to estimate the heat release rate and combustion efficiency of confined space pool fire combustion. The present invention provides fire safety technical support for buildings such as factories, equipment rooms, and oil depots. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a flow chart of the method for testing the temperature distribution of pool fire combustion in a confined space and estimating heat release according to the present invention.

[0089] Figure 2 Schematic diagram of a thermocouple tree according to an embodiment of the present invention.

[0090] Figure 3 Schematic top view of the central fire thermocouple tree according to an embodiment of the present invention.

[0091] Figure 4 2. It is a top view schematic diagram of the side wall fire thermocouple tree according to an embodiment of the present invention.

[0092] Figure 5 Schematic diagram of the heat flux measurement method according to an embodiment of the present invention.

[0093] Figure 6 Schematic diagram of probe arrangement of temperature sensors in the combustion pool according to an embodiment of the present invention. DETAILED DESCRIPTION

[0094] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the implementation mode of the present invention will be further clearly and completely described below in combination with the drawings in the implementation mode of the present invention. Obviously, the described implementation mode is only a part of the implementation mode of the present invention, not all implementation modes.

[0095] like Figures 1 to 6 As shown, this embodiment provides a method for testing the combustion temperature distribution and heat release estimation of a pool fire in a confined space, the method comprising the following steps:

[0096] S1. Design a thermocouple tree: Set up a thermocouple tree consisting of multiple thermocouples bundled together, receive the data signals measured by the thermocouples through a data acquisition card and transmit them to a computer for storage;

[0097] like Figure 2As shown, this embodiment measures the temperature distribution of a pool fire by designing a thermocouple tree consisting of three or more thermocouples bundled together. The number of thermocouples in the tree is proportional to the height of the combustion chamber. The thermocouple tree is suspended in the combustion chamber and protected by a stainless steel sleeve fixed to the top of the combustion chamber to prevent the thermocouples from moving. The thermocouple temperature probes face downward, and the temperature compensation wires of each thermocouple are passed through a wire hole in the top of the combustion chamber. The data signals measured by the thermocouples are received by a data acquisition card and transmitted to a computer for storage.

[0098] S2. Distributed temperature measurement points: Arrange thermocouple trees and set temperature measurement points according to the requirements of the central fire and / or side wall fire in the combustion chamber to obtain the temperature distribution in the combustion chamber.

[0099] A center fire is a simulation of a fire accident caused by flammable liquid leaking onto the combustion chamber floor, forming an oil pool (i.e., an oil pan) at the center of the floor. A fire simulation in which the center of gravity of the oil pool is at the center of the floor is considered a center fire.

[0100] The sidewall fire is a simulation test that simulates a fire accident caused by flammable liquid leaking onto the ground and gathering into an oil pool near the sidewall surface. The oil pool is considered to be close to the sidewall surface when the edge of the burning pool is adjacent to the sidewall surface.

[0101] In this embodiment, step S2 includes the following steps:

[0102] S21. Arrange the thermocouple tree described in step S1 in the combustion chamber. The dimensions of the combustion chamber are: length × width × height = a × b × c, where a, b, and c are all in meters. This embodiment needs to take into account the requirements of the combustion chamber center fire and / or side wall fire. The plane layout is as follows: Figure 3 and Figure 4 As shown. Arrange thermocouple trees starting from the center axis of the oil pan: for center fires, place a thermocouple tree every 0.5m; for side wall fires within a distance b / 2 from the center axis of the oil pan, place a thermocouple tree every 0.5m; for fires outside a distance b / 2 from the center axis of the oil pan, place a thermocouple tree every 1m.

[0103] S22. Estimation of flame height: The actual shape of the oil pan is diverse, so the actual area needs to be estimated. The diameter of the equivalent circle is calculated based on the area of ​​the oil pan. The flame height can be estimated using the relationship between the flame height and the oil pan diameter in formula (1):

[0104]

[0105] Where, L is the flame height, m;

[0106] D—equivalent diameter of oil pan, m;

[0107] —dimensionless heat release rate;

[0108] The dimensionless heat release rate According to formula (2), we can get:

[0109]

[0110] in,

[0111] —dimensionless heat release rate;

[0112] —heat release rate, kW;

[0113] ρ ∞ —Ambient air density, 1.2 kg / m 3 ;

[0114] c p —Specific heat capacity of ambient air, 1.0 kJ / (kg·K);

[0115] T ∞ —Ambient air temperature, 293K;

[0116] g—acceleration due to gravity, 9.81 kg·m / s;

[0117] D—Equivalent diameter of oil pan, m.

[0118] The heat release rate According to formula (3), we can get:

[0119]

[0120] in,

[0121] —heat release rate, kW;

[0122] x—combustion efficiency, taking the maximum value x=1.0;

[0123] —Solution burning rate, kg / s;

[0124] A f —Oil pan area, m 2 ;

[0125] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0126] ΔH c—Heat of combustion of the solution, MJ / kg.

[0127] S23. Setting temperature measurement points: Based on the estimated flame height, it is necessary to ensure that there are more than 3 temperature measurement points in the flame, and the temperature measurement points are evenly distributed in the flame. The thermocouples set at the temperature measurement points in the flame are 5mm diameter armored K-type thermocouples with a measuring range of 0 to 1300°C; in a closed or semi-sealed space, the thermocouples set at the temperature measurement points in the area outside the flame are all 1mm armored K-type thermocouples. When c / 8>0.5m, then, in addition to the flame area, a temperature measurement point is set at a spacing of every 0.5m along the height direction of the combustion chamber (i.e., thermocouples are arranged); when c / 8≤0.5m, then, in addition to the flame area, a temperature measurement point is set at a spacing of every c / 8 along the height direction of the combustion chamber (i.e., thermocouples are arranged).

[0128] S24. Obtaining the temperature distribution in the combustion chamber: The temperature data measured by the thermocouple can be used to calculate the temperature distribution at different locations on the central axis of the combustion chamber by using the point distance inverse interpolation method, or the temperature distribution results in the combustion chamber can be directly fitted using the contour module of the Origin curve software.

[0129] S3. Measure the heat flux and estimate the heat release rate.

[0130] S31. Measurement of heat flux density: The measurement of heat flux density during combustion of fuel solution in the combustion chamber includes the measurement of radiation heat flux density and the measurement of convection heat flux density, which are monitored and measured using a radiation heat flux density meter and a convection heat flux density meter respectively.

[0131] In this embodiment, the Figure 5 The heat flux density measurement method shown in the figure uses two sets of heat flux density sensors, including a first heat flux density sensor and a second heat flux density sensor, installed at the monitoring point. Each set includes a radiation heat flux meter and a convection heat flux meter. The first heat flux density sensor monitors the heat flux density horizontally in the plane of the flame center, while the second heat flux density sensor monitors the heat flux density at a 45° angle to the horizontal plane of the flame center. The horizontal distance between the monitoring point of the first and second heat flux density sensors and the center of the combustion pool flame is adjusted according to the actual oil pan size. The distance increases with the size of the oil pan to prevent the flame from burning the sensors.

[0132] Optionally, the horizontal distance between the monitoring points where the first heat flux density sensor and the second heat flux density sensor are located and the center of the combustion pool flame is 1.2 m.

[0133] S32. Estimate heat release rate: Calculate the heat release rate of the monitoring point horizontal to the horizontal plane where the flame center is located and the heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located.

[0134] The heat release rate of the fuel solution combustion in the combustion chamber is calculated according to the following formula (4):

[0135] Q s =Q x +Q r +Q d (4)

[0136] in,

[0137] Q s —Solution combustion heat release rate, J / s;

[0138] Q x —Solution heat absorption rate, J / s;

[0139] Q r —Radiative heat release rate, J / s;

[0140] Q d —Convective heat release rate, J / s.

[0141] The heat absorption rate Q of the solution x It can be calculated according to formula (5):

[0142]

[0143] in,

[0144] Q x —Solution heat absorption rate, kW;

[0145] C p —Specific heat capacity of the burning solution, kJ / (kg·K);

[0146] T f —Flame temperature of the solution surface, °C;

[0147] T l —Temperature of the solution, °C;

[0148] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0149] A f —Oil pan area, m 2 .

[0150] Among them, the flame temperature T of the solution surface f and the temperature inside the solution, T l The temperature is obtained by the temperature sensor arranged in the combustion pool. The probe arrangement of the temperature sensor in the combustion pool (i.e. the temperature measurement point) is as follows Figure 6 As shown, there are 4 temperature measurement points in total: ① The first temperature measurement point is set in the fuel solution to monitor the temperature T inside the fuel solution. l ; ② The second temperature measurement point is set on the wall of the combustion pool at the same height as the first temperature measurement point, which is used to measure the temperature of the combustion pool wall; ③ The third temperature measurement point is arranged above the fuel liquid surface, which can monitor the flame temperature T of the solution surface during the combustion process f ④ The fourth temperature measurement point is set on the combustion pool wall at the same height as the third temperature measurement point to monitor the temperature at that wall location. The temperature measurement points set on the combustion pool wall (the second and fourth temperature measurement points) use patch-type temperature sensors, while the first and third temperature measurement points use 5mm diameter K-type armored thermocouples.

[0151] Optionally, the third temperature measurement point is arranged above the fuel liquid surface, 1 to 3 cm away from the fuel liquid surface. In another preferred embodiment, the third temperature measurement point is arranged above the fuel liquid surface, 2 cm away from the fuel liquid surface.

[0152] The radiative heat release rate Q r The radiation heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located or the radiation heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located is calculated according to the following formula (6):

[0153] Q r =(4πr 2 / t c )h fr (6)

[0154] in,

[0155] Q r —Radiative heat release rate, J / s;

[0156] r—the distance between the monitoring point and the flame center, m;

[0157] t c —Penetration coefficient, select value 1;

[0158] h fr —Radiant heat flux, W·m -2 .

[0159] The convective heat release rate Q dThe convective heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located or the convective heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located is calculated according to the following formula (7):

[0160] Q d =(4πr 2 / t c )h fd (7)

[0161] in,

[0162] Q d —Convective heat release rate, J / s;

[0163] r—the distance between the monitoring point and the flame center, m;

[0164] t c —Penetration coefficient, select value 1;

[0165] h fd —Convective heat flux, W·m -2 .

[0166] S33. Estimation of combustion efficiency: Calculate the combustion efficiency of the horizontal monitoring point on the horizontal plane where the flame center is located and the combustion efficiency of the monitoring point at a 45° angle to the horizontal plane where the flame center is located. The combustion efficiency of the fuel solution is the average of the combustion efficiency of the horizontal monitoring point and the combustion efficiency of the monitoring point at a 45° angle. Calculate the combustion efficiency of the horizontal monitoring point on the horizontal plane where the flame center is located and the combustion efficiency of the monitoring point at a 45° angle to the horizontal plane where the flame center is located according to the following formula (8):

[0167]

[0168] in,

[0169] η—solution combustion efficiency, J / s;

[0170] Q s —Solution combustion heat release rate, J / s;

[0171] A f —Oil pan area, m 2 ;

[0172] —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D );

[0173] ΔH c—Heat of combustion of the solution, MJ / kg.

[0174] The methods described herein are not limited to the specific embodiments described. The embodiments described above are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or in other specific forms without departing from the gist or essential characteristics of the present invention. Therefore, the embodiments described herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is to be determined by the appended claims, and any variations that are equivalent to the intent and scope of the claims are intended to be within the scope of the present invention.

Claims

1. A method for testing the combustion temperature distribution and estimating heat release of a pool fire in a confined space, characterized by: The method comprises the following steps: S1. Designing a thermocouple tree: setting up a thermocouple tree formed by bundling multiple thermocouples, and transmitting data signals measured by the thermocouples to a computer for storage; S2. Distributing temperature measurement points: Arranging the thermocouple tree and setting temperature measurement points to obtain the temperature distribution in the combustion chamber; The thermocouple tree is suspended in the combustion chamber, and the outside of the thermocouple tree is protected by a stainless steel sleeve, which is fixed to the top of the combustion chamber; The temperature compensation wire of the thermocouple passes through the wire hole preset on the top of the combustion chamber; The data signal measured by the thermocouple is received by a data acquisition card and transmitted to a computer for storage; The thermocouple trees are arranged as follows: according to the requirements of the center fire and / or side wall fire of the combustion chamber, the thermocouple trees are arranged in the combustion chamber with length, width and height dimensions a, b and c respectively: the thermocouple trees are arranged starting from the central axis of the oil pan, and a thermocouple tree is arranged every 0.5m for the center fire; the thermocouple trees are arranged every 0.5m for the side wall fire within a distance b / 2 from the center axis of the oil pan, and every 1m for the side wall fire beyond a distance b / 2 from the center axis of the oil pan; S3. Measure heat flux density and estimate heat release rate and combustion efficiency; The heat flux density measurement method comprises: setting two groups of heat flux density sensors at a monitoring point, including a first heat flux density sensor and a second heat flux density sensor; each group of heat flux density sensors includes a radiation heat flux meter and a convection heat flux meter, respectively used to measure radiation heat flux density and convection heat flux density; the first heat flux density sensor is used to monitor the heat flux density in the horizontal direction of the horizontal plane where the flame center is located, and the second heat flux density sensor is used to monitor the heat flux density at a 45° angle to the horizontal plane where the flame center is located; The combustion efficiency estimation method is as follows: the combustion efficiency of the horizontal monitoring point on the horizontal plane where the flame center is located and the combustion efficiency of the monitoring point at a 45° angle to the horizontal plane where the flame center is located are calculated respectively; the combustion efficiency of the fuel solution is taken as the average of the combustion efficiency of the horizontal monitoring point and the combustion efficiency of the monitoring point at a 45° angle.

2. A method for measuring the temperature distribution and estimating heat release of a confined space pool fire according to claim 1, characterized in that: The step S2 comprises the following steps: S21. Arranging the thermocouple tree in the combustion chamber; S22, estimate the flame height; S23. Setting temperature measurement points: Based on the estimated flame height, ensure that there are three or more temperature measurement points in the flame, and that the temperature measurement points are evenly distributed in the flame; S24. Obtain the temperature distribution in the combustion chamber.

3. A method for measuring the combustion temperature distribution and estimating heat release in a confined space pool fire according to claim 2, characterized in that: The flame height is estimated by formula (1): in, L—flame height, m; D—equivalent diameter of oil pan, m; —dimensionless heat release rate; The dimensionless heat release rate According to formula (2), we can get: in, —dimensionless heat release rate; —heat release rate, kW; ρ ∞ — Ambient air density, 1.2 kg / m 3 ; c p —Specific heat capacity of ambient air, 1.0 kJ / (kg·K); T ∞ —Ambient air temperature, 293K; g—acceleration due to gravity, 9.81 kg·m / s; D—equivalent diameter of oil pan, m; The heat release rate According to formula (3), we can get: in, —heat release rate, kW; x—combustion efficiency, taking the maximum value x=1.0; —Solution burning rate, kg / s; A f —Oil pan area, m 2 ; —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D ); ΔH c —Heat of combustion of the solution, MJ / kg.

4. The method for measuring the combustion temperature distribution and estimating the heat release of a confined space pool fire according to claim 1, wherein: When c / 8>0.5m, a temperature measurement point is set at every 0.5m along the height direction of the combustion chamber except the flame area; when c / 8≤0.5m, a temperature measurement point is set at every c / 8 along the height direction of the combustion chamber except the flame area; The thermocouples set at the temperature measurement points in the flame are 5mm diameter armored K-type thermocouples with a measuring range of 0 to 1300°C; in closed or semi-sealed spaces, the thermocouples set at the temperature measurement points outside the flame are all 1mm armored K-type thermocouples.

5. The method for measuring the temperature distribution and estimating the heat release of a pool fire in a confined space according to claim 1, wherein: The temperature distribution at different locations on the central axis of the combustion chamber is calculated by the point distance inverse interpolation method; or the temperature distribution results in the combustion chamber are directly generated by fitting the contour module of the Origin curve software.

6. The method for measuring temperature distribution and estimating heat release in a confined space pool fire according to claim 1, wherein: The horizontal distance between the monitoring point and the center of the combustion pool flame is adjusted according to the actual oil pan size. As the oil pan increases, the distance increases accordingly to avoid the flame burning the sensor.

7. A method for measuring temperature distribution and estimating heat release in a confined space pool fire according to claim 4, characterized in that: The heat release rate estimation refers to calculating the heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located and the heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located. The heat release rate is calculated according to the following formula (4): Q s =Q x +Q r +Q d (4) in, Q s —Solution combustion heat release rate, J / s; Q x —Solution heat absorption rate, J / s; Q r —Radiative heat release rate, J / s; Q d —Convective heat release rate, J / s; The heat absorption rate Q of the solution x It can be calculated according to formula (5): in, Q x —Solution heat absorption rate, kW; C p —Specific heat capacity of the burning solution, kJ / (kg·K); T f —Flame temperature of the solution surface, °C; T l —Temperature of the solution, °C; —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D ); A f —Oil pan area, m 2 ; The radiative heat release rate Q r is the radiation heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located, or the radiation heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the radiation heat release rate of the horizontal monitoring point on the horizontal plane where the flame center is located and the radiation heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated according to formula (6): Q r =(4πr 2 / t c )h fr (6) in, Q r —Radiative heat release rate, J / s; r—the distance between the monitoring point and the flame center, m; t c —Penetration coefficient, select value 1; h fr —Radiant heat flux, W·m -2 ; The convective heat release rate Q d is the convective heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located, or the convective heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located; the convective heat release rate of the monitoring point in the horizontal direction of the horizontal plane where the flame center is located and the convective heat release rate of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated according to formula (7): Q d =(4πr 2 / t c )h fd (7) in, Q d —Convective heat release rate, J / s; r—the distance between the monitoring point and the flame center, m; t c —Penetration coefficient, select value 1; h fd —Convective heat flux, W·m -2 .

8. The method for measuring temperature distribution and estimating heat release in a confined space pool fire according to claim 1, wherein: According to formula (8), the combustion efficiency of the monitoring point horizontal to the horizontal plane where the flame center is located and the combustion efficiency of the monitoring point at an angle of 45° to the horizontal plane where the flame center is located are calculated respectively: in, η — Solution combustion efficiency, J / s; Q s —Solution combustion heat release rate, J / s; A f —Oil pan area, m 2 ; —Solution burning rate, kg / (m 2 ·s), refer to the kerosene calculation formula 0.022(1-e -4.5D ); ΔH c —Heat of combustion of the solution, MJ / kg.

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