阅读说明：本技术 实验室内超低温环境下飞机apu高温尾气降温排放方法 (Method for cooling and discharging high-temperature tail gas of airplane APU (auxiliary Power Unit) in ultralow-temperature environment in laboratory ) 是由 成竹 吴敬涛 任战鹏 李剑 杜文辉 于 2021-12-10 设计创作，主要内容包括：本发明公开了一种实验室内超低温环境下飞机APU高温尾气降温排放方法,包括步骤：一、风机选型；二、给定飞机APU高温尾气排放安全设定温度；三、确定电伴热带的加热温度；四、预估喷淋降温用水质量流量；五、飞机APU高温尾气初级降温排放；六、尾气排放温度检测与调节；七、飞机APU高温尾气持续降温排放。本发明利用实验室内排气口温度传感器、实验室环境温度传感器和实验室环境压力传感器检测APU开车条件下室内环境是否平衡,进而选定满足需求的风机类型,保证了实验室内温度、压力的稳定,确保了飞机及试验人员的安全,确定电伴热带的加热温度,有效防止供水管不会结冰冻结堵塞,在实验室内超低温环境下仍然具有稳定性。(The invention discloses a method for cooling and discharging high-temperature tail gas of an aircraft APU (auxiliary Power Unit) in an ultralow-temperature environment in a laboratory, which comprises the following steps: firstly, selecting a type of a fan; setting the safe set temperature for the high-temperature tail gas emission of the aircraft APU; thirdly, determining the heating temperature of the electric tracing band; fourthly, estimating the mass flow of the water for spraying and cooling; fifthly, primarily cooling and discharging high-temperature tail gas of the aircraft APU; sixthly, detecting and adjusting the exhaust gas emission temperature; and seventhly, continuously cooling and discharging the high-temperature tail gas of the aircraft APU. The invention utilizes the temperature sensor of the exhaust port in the laboratory, the temperature sensor of the environment in the laboratory and the pressure sensor of the environment in the laboratory to detect whether the environment in the laboratory is balanced under the driving condition of the APU, and then selects the type of the fan meeting the requirement, thereby ensuring the stability of the temperature and the pressure in the laboratory, ensuring the safety of the airplane and the testing personnel, determining the heating temperature of the electric tracing band, effectively preventing the water supply pipe from being frozen and blocked, and still having the stability in the ultralow temperature environment in the laboratory.)

1. A method for cooling and discharging high-temperature tail gas of an aircraft APU (auxiliary Power Unit) in a laboratory under an ultralow temperature environment comprises the steps of discharging and cooling the exhaust gas of the aircraft APU by utilizing a laboratory aircraft APU exhaust system, wherein the laboratory aircraft APU exhaust system comprises a laboratory (6) for accommodating an aircraft (7) and aircraft APU exhaust equipment for outputting the exhaust gas of the aircraft APU to the outside, the aircraft APU exhaust equipment comprises an initial adjusting pipeline (1), a drainage pipeline (2), a butterfly valve (3) and a fan (4) which are sequentially connected, a spray cooler (5) is arranged on the initial adjusting pipeline (1), the spray cooler (5) comprises a plurality of spray cooling mechanisms uniformly arranged along the length direction of the initial adjusting pipeline (1), the spray cooling mechanisms comprise water supply pipes (5-2) arranged outside the initial adjusting pipeline (1) and a plurality of spray ring pipes (5-1) uniformly arranged on the inner wall of the initial adjusting pipeline (1) along the length direction of the initial adjusting pipeline (1), a plurality of water spray holes are uniformly formed in the side wall of the spray ring pipe (5-1) facing the inner center direction of the initial adjusting pipeline (1);

the water supply pipe (5-2) is provided with an input pipe and a plurality of output pipes, the number of the output pipes on the water supply pipe (5-2) is equal to the number of the spray ring pipes (5-1) in the spray cooling mechanism and corresponds to one another, and the output pipes are provided with valves (5-3) and flow sensors (5-4);

the water supply pipe (5-2) is wrapped with an electric tracing band (5-5) in a winding way, and the electric tracing band (5-5) is wrapped with heat insulation cotton in a winding way;

an exhaust port temperature sensor (8) is arranged in the laboratory (6) at a position which is close to the 3m exhaust position of the airplane APU, and a laboratory environment temperature sensor (9) and a laboratory environment pressure sensor (10) are arranged in the laboratory (6) at a position which is in the non-working area of the airplane;

the initial adjusting pipeline (1) and the drainage pipeline (2) are both round pipes;

the method is characterized by comprising the following steps:

step one, fan type selection: adjusting the temperature in the laboratory (6) to an ultralow temperature set value, acquiring the temperature at a position 3m outside an exhaust port of the aircraft APU in real time by using an exhaust port temperature sensor (8), and acquiring the environmental temperature in the laboratory in real time by using a laboratory environment temperature sensor (9);

gradually increasing the frequency of the fan (4), increasing and then reducing the temperature value at the position of the exhaust port temperature sensor (8) in the laboratory, wherein the temperature value at the position of the exhaust port temperature sensor (8) in the laboratory is the same as the temperature value at the position of the laboratory environment temperature sensor (9), the pressure at the position of the laboratory environment pressure sensor (10) in the laboratory meets the micro-positive pressure index, stopping adjusting the frequency of the fan (4), and selecting the fan type meeting the requirement;

setting the safe set temperature for the high-temperature tail gas emission of the airplane APU;

step three, determining the heating temperature of the electric tracing band: starting the electric tracing band (5-5), maintaining the surface temperature of the water supply pipe (5-2) at a set temperature, and determining the heating temperature of the electric tracing band (5-5) at the moment;

estimating the mass flow of the water for spraying and cooling: according to the formulaMass flow of water for spraying and cooling is estimatedWherein, in the step (A),to initially adjust the mass flow rate of the gas stream in the duct,to initially adjust the average specific heat capacity of the air flow in the duct,to initially adjust the temperature of the air flow within the duct,the temperature is set for the safety of the tail gas emission,the percentage of water evaporation is used for spray cooling, the beta is the safety coefficient of water consumption,the specific heat capacity of water, delta T is the temperature variation of the water vapor changed from the initial temperature by the spraying cooling water, and delta Q is the specific latent heat of vaporization of the water;

step five, primary cooling emission of high-temperature tail gas of the aircraft APU: the plurality of spraying cooling mechanisms perform primary spraying cooling on the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline (1) according to the mass flow of the water used in the step four;

step six, detecting and adjusting the exhaust emission temperature: detecting the temperature of the tail gas at the discharge part of the drainage pipeline (2) by using a tail gas discharge temperature detector (11);

the tail gas emission temperature detector (11) comprises a first temperature sensor (11-1), a second temperature sensor (11-2), a third temperature sensor (11-3), a fourth temperature sensor (11-4), a fifth temperature sensor (11-5) and a sixth temperature sensor (11-6) which are arranged in a coplanar manner;

taking the average value of the temperatures measured by the first temperature sensor (11-1), the second temperature sensor (11-2), the third temperature sensor (11-3), the fourth temperature sensor (11-4), the fifth temperature sensor (11-5) and the sixth temperature sensor (11-6) as the actual exhaust emission temperature;

when the actual exhaust gas temperature is higher than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, increasing the water consumption safety coefficient beta in the fourth step, further increasing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

when the actual exhaust gas temperature is lower than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, reducing the water consumption safety coefficient beta in the fourth step, further reducing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

seventhly, continuously cooling and discharging high-temperature tail gas of the aircraft APU: and calculating the final mass flow of the water for spraying and cooling by using the final value of the water consumption safety coefficient beta in the step six, and continuously spraying and cooling the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline (1) by the plurality of spraying and cooling mechanisms according to the final mass flow of the water for spraying and cooling until the aircraft APU is closed.

2. The method for cooling and discharging the high-temperature tail gas of the APU of the airplane in the laboratory ultralow temperature environment according to claim 1 is characterized in that: the water consumption safety coefficient beta is 1.5-2.

3. The method for cooling and discharging the high-temperature tail gas of the APU of the airplane in the laboratory ultralow temperature environment according to claim 1 is characterized in that: the micro-positive pressure index is 10 Pa-80 Pa.

4. The method for cooling and discharging the high-temperature tail gas of the APU of the airplane in the laboratory ultralow temperature environment according to claim 1 is characterized in that: the safe set temperature of the exhaust emissionNot more than 80 ℃; the ultralow temperature set value is not higher than-50 ℃; the set temperature is 10-15 ℃.

5. The method for cooling and discharging the high-temperature tail gas of the APU of the airplane in the laboratory ultralow temperature environment according to claim 1 is characterized in that: the water supply pipe (5-2) is a water supply pipe having one input pipe and two to four output pipes.

6. The method for cooling and discharging the high-temperature tail gas of the APU of the airplane in the laboratory ultralow temperature environment according to claim 1 is characterized in that: the first temperature sensor (11-1), the second temperature sensor (11-2), the third temperature sensor (11-3), the fourth temperature sensor (11-4), the fifth temperature sensor (11-5) and the sixth temperature sensor (11-6) are arranged at the positions of every 1/6 radius width and 60 degrees of turning angle in the radius direction of the pipeline by taking the central point of the pipeline as a starting point.

Technical Field

The invention belongs to the technical field of APU (auxiliary Power Unit) drainage, exhaust and cooling in the starting process of an APU (auxiliary Power Unit) of an airplane in a closed laboratory, and particularly relates to a method for cooling and discharging high-temperature tail gas of the APU of the airplane in an ultralow-temperature environment in the laboratory.

Background

The weather experiment is carried out in a full-aircraft climate laboratory, and an aircraft APU needs to be started to provide power for the aircraft. If the high-temperature and high-pressure tail gas discharged by the APU is directly discharged into a laboratory, the temperature and pressure environment in the laboratory can be damaged, and meanwhile, the tail gas is accumulated in the laboratory, so that the safety of the laboratory, an airplane and even testing personnel can be threatened. Therefore, when the aircraft APU is turned on in a laboratory, the exhaust gas needs to be discharged outside the laboratory. The aircraft APU exhaust equipment in the laboratory comprises an initial adjusting pipeline, a drainage pipeline used for discharging gas out of the laboratory and a fan arranged at the exhaust end of the drainage pipeline, wherein a spray cooling device is arranged in the initial adjusting pipeline, the existing spray cooling device has huge spray water amount and is wasteful of resources, in addition, the existing aircraft can often carry out aircraft climate tests in an ultralow temperature environment below-50 ℃, when the ultralow temperature environment test is carried out in the laboratory, on one hand, the temperature in the laboratory is extremely low, on the other hand, the aircraft tail gas still is high-temperature and high-pressure gas after entering the drainage pipeline, when the ultralow temperature environment test is carried out, the water spray link is adopted to cool the high-temperature tail gas, meanwhile, the spray water is required to be prevented from freezing at the temperature, and the blockage caused by the freezing of accumulated water at the low temperature is prevented, therefore, the aircraft APU exhaust equipment in the laboratory which saves material resources and manpower is absent at present, and an important foundation is laid for the development of an extreme climate test in a laboratory.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art and provides a method for cooling and discharging high-temperature tail gas of an aircraft APU (auxiliary Power Unit) in a laboratory ultralow temperature environment, which determines the tail gas amount which can be accommodated by an initial adjusting pipeline through the length of the initial adjusting pipeline so as to determine the water spraying amount of a spraying and cooling mechanism, detects whether the indoor environment is balanced under the driving condition of the APU by using an exhaust port temperature sensor, a laboratory environment temperature sensor and a laboratory environment pressure sensor in the laboratory, further selects the fan type meeting the requirement, ensures the stability of the temperature and the pressure in the laboratory, ensures the safety of the aircraft and testers, determines the heating temperature of an electric tracing band, effectively prevents a water supply pipe from being frozen and blocked, still has stability in the laboratory ultralow temperature environment, detects whether the tail gas temperature at the discharge position of a drainage pipeline reaches the design requirement by using a tail gas discharge temperature detector, and then provide the basis for adjusting the water consumption and realizing temperature control, guarantee the simulation of extreme climate in the laboratory, convenient to popularize and use.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for cooling and discharging high-temperature tail gas of an aircraft APU in an ultralow temperature environment in a laboratory utilizes an exhaust system of the aircraft APU in the laboratory to discharge and cool the exhaust gas of the aircraft APU, the laboratory aircraft APU exhaust system comprises a laboratory for accommodating an aircraft and aircraft APU exhaust equipment for outputting the exhaust of the aircraft APU to the outside, the aircraft APU exhaust equipment comprises an initial adjusting pipeline, a drainage pipeline, a butterfly valve and a fan which are sequentially connected, a spray cooler is arranged on the initial adjusting pipeline, the spray cooler comprises a plurality of spray cooling mechanisms which are uniformly arranged along the length direction of the initial adjusting pipeline, the spraying cooling mechanism comprises a water supply pipe arranged outside the initial adjusting pipeline and a plurality of spraying ring pipes uniformly arranged on the inner wall of the initial adjusting pipeline along the length direction of the initial adjusting pipeline, a plurality of water spray holes are uniformly formed in the side wall of the spray ring pipe facing the inner center direction of the initial adjustment pipeline;

the water supply pipe is provided with an input pipe and a plurality of output pipes, the number of the output pipes on the water supply pipe is equal to the number of the spraying ring pipes in the spraying and cooling mechanism and corresponds to the number of the spraying ring pipes one by one, and the output pipes are provided with valves and flow sensors;

an electric tracing band is wound and wrapped outside the water supply pipe, and heat insulation cotton is wound and wrapped outside the electric tracing band;

an exhaust port temperature sensor is arranged in the position, which is close to the 3m position of the airplane APU exhaust in the laboratory, and a laboratory environment temperature sensor and a laboratory environment pressure sensor are arranged in the position, which is located in the non-working area of the airplane, in the laboratory;

the initial adjusting pipeline and the drainage pipeline are both round pipes;

the method is characterized by comprising the following steps:

step one, fan type selection: adjusting the temperature in the laboratory to an ultralow temperature set value, acquiring the temperature at a position 3m away from the exhaust port of the aircraft APU in real time by using an exhaust port temperature sensor, and acquiring the environmental temperature in the laboratory in real time by using a laboratory environment temperature sensor;

gradually increasing the frequency of the fan, increasing and then reducing the temperature value at the position of the exhaust port temperature sensor in the laboratory, wherein the temperature value at the position of the exhaust port temperature sensor in the laboratory is the same as the temperature value at the position of the laboratory environment temperature sensor in the laboratory, the pressure at the position of the laboratory environment pressure sensor in the laboratory meets the micro-positive pressure index, stopping adjusting the frequency of the fan, and selecting the fan type meeting the requirement;

setting the safe set temperature for the high-temperature tail gas emission of the airplane APU;

step three, determining the heating temperature of the electric tracing band: starting the electric tracing band to maintain the surface temperature of the water supply pipe at a set temperature, and determining the heating temperature of the electric tracing band at the moment;

estimating the mass flow of the water for spraying and cooling: according to the formulaMass flow of water for spraying and cooling is estimatedWherein, in the step (A),to initially adjust the mass flow rate of the gas stream in the duct,to initially adjust the average specific heat capacity of the air flow in the duct,to initially adjust the temperature of the air flow within the duct,for exhaust gas emissionThe temperature is set to be safe,the percentage of water evaporation is used for spray cooling, the beta is the safety coefficient of water consumption,the specific heat capacity of water, delta T is the temperature variation of the water vapor changed from the initial temperature by the spraying cooling water, and delta Q is the specific latent heat of vaporization of the water;

step five, primary cooling emission of high-temperature tail gas of the aircraft APU: the plurality of spraying cooling mechanisms perform primary spraying cooling on the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline according to the water mass flow in the step four;

step six, detecting and adjusting the exhaust emission temperature: detecting the temperature of the tail gas at the discharge position of the drainage pipeline by using a tail gas discharge temperature detector;

the tail gas emission temperature detector comprises a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor and a sixth temperature sensor which are arranged in a coplanar manner;

taking the average value of the temperatures measured by the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor and the sixth temperature sensor as the actual exhaust emission temperature;

when the actual exhaust gas temperature is higher than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, increasing the water consumption safety coefficient beta in the fourth step, further increasing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

when the actual exhaust gas temperature is lower than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, reducing the water consumption safety coefficient beta in the fourth step, further reducing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

seventhly, continuously cooling and discharging high-temperature tail gas of the aircraft APU: and calculating the final mass flow of the water for spraying and cooling by using the final value of the water consumption safety coefficient beta in the step six, and continuously spraying and cooling the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline by the plurality of spraying and cooling mechanisms according to the final mass flow of the water for spraying and cooling until the aircraft APU is closed.

The method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow-temperature environment in the laboratory is characterized in that: the water consumption safety coefficient beta is 1.5-2.

The method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow-temperature environment in the laboratory is characterized in that: the micro-positive pressure index is 10 Pa-80 Pa.

The method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow-temperature environment in the laboratory is characterized in that: the safe set temperature of the exhaust emissionNot more than 80 ℃; the ultralow temperature set value is not higher than-50 ℃; the set temperature is 10-15 ℃.

The method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow-temperature environment in the laboratory is characterized in that: the water supply pipe is a water supply pipe having one input pipe and two to four output pipes.

The method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow-temperature environment in the laboratory is characterized in that: the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the fifth temperature sensor and the sixth temperature sensor are arranged at the position of every 1/6 radius widths and 60-degree turning angles in the radius direction of the pipeline by taking the central point of the pipeline as a starting point.

Compared with the prior art, the invention has the following advantages:

1. the invention adjusts the indoor temperature to reach the ultralow temperature set value, simulates the extreme environment, detects whether the indoor environment is balanced under the driving condition of the APU by utilizing the temperature sensor of the exhaust port in the laboratory, the temperature sensor of the environment in the laboratory and the pressure sensor of the environment in the laboratory, and further selects the type of the fan meeting the requirement, thereby ensuring the stability of the temperature and the pressure in the laboratory, ensuring the safety of the airplane and the tester and being convenient for popularization and use.

2. The electric tracing band has the temperature-controllable heating function, can maintain the surface temperature of the water supply pipe within a set temperature range, can be automatically disconnected after the temperature is reached, and can be restarted after the temperature is lower than the set temperature, so that the heating temperature of the pipeline is ensured, the phenomenon that the heat-insulating cotton is burnt even the electric tracing band is short-circuited and burnt due to overhigh local temperature in the traditional electric heating uncontrollable way can be prevented, the aim of spraying and cooling high-temperature tail gas in the pipeline in an ultralow temperature environment is fulfilled, and the use effect is good.

3. The method has simple steps, determines the tail gas amount which can be accommodated by the initial adjusting pipeline through the length of the initial adjusting pipeline so as to determine the water spraying amount of the spraying and cooling mechanism, still has stability in the ultralow temperature environment in the laboratory, ensures the simulation of extreme climate in the laboratory, and is convenient for popularization and use.

In conclusion, the tail gas amount which can be accommodated by the initial adjusting pipeline is determined through the length of the initial adjusting pipeline, the water spraying amount of the spraying and cooling mechanism is further determined, whether the indoor environment is balanced under the driving condition of the APU is detected by utilizing the temperature sensor of the exhaust port in the laboratory, the temperature sensor of the environment in the laboratory and the pressure sensor of the environment in the laboratory, the fan type meeting the requirement is further selected, the stability of the temperature and the pressure in the laboratory is ensured, the safety of an airplane and testing personnel is ensured, the heating temperature of the electric tracing band is determined, the water supply pipe is effectively prevented from being frozen and blocked, the stability is still provided under the ultralow temperature environment in the laboratory, the simulation of the extreme climate in the laboratory is ensured, and the popularization and the use are convenient.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a layout diagram of an aircraft APU exhaust system in a laboratory of the present invention.

Fig. 2 is a schematic structural view of the exhaust mechanism of the present invention.

FIG. 3 is a schematic view of the connection between the spray cooler and the initial adjustment pipe according to the present invention.

FIG. 4 is a schematic view showing the arrangement of the electric tracing band outside the water supply pipe according to the present invention.

FIG. 5 is a schematic diagram of the arrangement of the tail gas emission temperature detector at the tail of the drainage pipeline.

FIG. 6 is a block flow diagram of a method of the present invention.

Description of reference numerals:

1-initial adjustment of the pipeline; 2-a drainage pipeline; 3, a butterfly valve;

4, a fan; 5, a spray cooler; 5-1-spraying ring pipe;

5-2-water supply pipe; 5-3-valve; 5-4-flow sensor;

5-electric tracing band; 6-laboratory; 7-an airplane;

8-exhaust port temperature sensor; 9-a laboratory ambient temperature sensor;

10-a laboratory ambient pressure sensor; 11-exhaust emission temperature detector;

11-1 — a first temperature sensor; 11-2 — a second temperature sensor;

11-3 — a third temperature sensor; 11-4-a fourth temperature sensor;

11-5-a fifth temperature sensor; 11-6-sixth temperature sensor.

Detailed Description

As shown in fig. 1 to 6, the method for cooling and discharging the high-temperature tail gas of the aircraft APU in the ultralow temperature environment in the laboratory of the present invention comprises discharging and cooling the exhaust gas of the aircraft APU by using a laboratory aircraft APU exhaust system in the laboratory, wherein the laboratory aircraft APU exhaust system in the laboratory comprises a laboratory 6 for accommodating an aircraft 7 and aircraft APU exhaust equipment for outputting the exhaust gas of the aircraft APU to the outside, the aircraft APU exhaust equipment comprises an initial adjusting pipeline 1, a drainage pipeline 2, a butterfly valve 3 and a fan 4 which are connected in sequence, a spray cooler 5 is arranged on the initial adjusting pipeline 1, the spray cooler 5 comprises a plurality of spray cooling mechanisms uniformly arranged along the length direction of the initial adjusting pipeline 1, the spray cooling mechanisms comprise a water supply pipe 5-2 arranged outside the initial adjusting pipeline 1 and a plurality of spray ring pipes 5-1 uniformly arranged on the inner wall of the initial adjusting pipeline 1 along the length direction of the initial adjusting pipeline 1, a plurality of water spray holes are uniformly formed in the side wall of the spray ring pipe 5-1 facing the inner center direction of the initial adjustment pipeline 1;

the water supply pipe 5-2 is provided with an input pipe and a plurality of output pipes, the number of the output pipes on the water supply pipe 5-2 is equal to the number of the spray ring pipes 5-1 in the spray cooling mechanism and corresponds to one, and the output pipes are provided with valves 5-3 and flow sensors 5-4;

the water supply pipe 5-2 is externally wound and wrapped with an electric tracing band 5-5, and the electric tracing band 5-5 is externally wound and wrapped with heat insulation cotton;

an exhaust port temperature sensor 8 is arranged in the position, close to the 3m position of the airplane APU exhaust, in the laboratory 6, and a laboratory environment temperature sensor 9 and a laboratory environment pressure sensor 10 are arranged in the position, located in the airplane non-working area, in the laboratory 6;

the initial adjusting pipeline 1 and the drainage pipeline 2 are both round pipes;

the method comprises the following steps:

step one, fan type selection: adjusting the temperature in the laboratory 6 to an ultralow temperature set value, acquiring the temperature at a position 3m away from the exhaust port of the aircraft APU in real time by using an exhaust port temperature sensor 8, and acquiring the environmental temperature in the laboratory in real time by using a laboratory environment temperature sensor 9;

gradually increasing the frequency of the fan 4, increasing and then reducing the temperature value at the position of the exhaust port temperature sensor 8 in the laboratory, wherein the temperature value at the position of the exhaust port temperature sensor 8 in the laboratory is the same as the temperature value at the position of the laboratory environment temperature sensor 9 in the laboratory, the pressure at the position of the laboratory environment pressure sensor 10 in the laboratory meets the micro-positive pressure index, stopping adjusting the frequency of the fan 4, and selecting the fan type meeting the requirement;

setting the safe set temperature for the high-temperature tail gas emission of the airplane APU;

step three, determining the heating temperature of the electric tracing band: starting the electric tracing band 5-5 to maintain the surface temperature of the water supply pipe 5-2 at a set temperature, and determining the heating temperature of the electric tracing band 5-5 at the moment;

estimating the mass flow of the water for spraying and cooling: according to the formulaMass flow of water for spraying and cooling is estimatedWherein, in the step (A),to initially adjust the mass flow rate of the gas stream in the duct,to initially adjust the average specific heat capacity of the air flow in the duct,to initially adjust the temperature of the air flow within the duct,the temperature is set for the safety of the tail gas emission,the percentage of water evaporation is used for spray cooling, the beta is the safety coefficient of water consumption,the specific heat capacity of water, delta T is the temperature variation of the water vapor changed from the initial temperature by the spraying cooling water, and delta Q is the specific latent heat of vaporization of the water;

step five, primary cooling emission of high-temperature tail gas of the aircraft APU: the plurality of spraying cooling mechanisms perform primary spraying cooling on the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline 1 according to the water mass flow in the step four;

step six, detecting and adjusting the exhaust emission temperature: detecting the temperature of the tail gas at the discharge part of the drainage pipeline 2 by using a tail gas discharge temperature detector 11;

the exhaust emission temperature detector 11 comprises a first temperature sensor 11-1, a second temperature sensor 11-2, a third temperature sensor 11-3, a fourth temperature sensor 11-4, a fifth temperature sensor 11-5 and a sixth temperature sensor 11-6 which are arranged in a coplanar manner;

taking the average value of the temperatures measured by the first temperature sensor 11-1, the second temperature sensor 11-2, the third temperature sensor 11-3, the fourth temperature sensor 11-4, the fifth temperature sensor 11-5 and the sixth temperature sensor 11-6 as the actual exhaust emission temperature;

when the actual exhaust gas temperature is higher than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, increasing the water consumption safety coefficient beta in the fourth step, further increasing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

when the actual exhaust gas temperature is lower than the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, reducing the water consumption safety coefficient beta in the fourth step, further reducing the mass flow of water for spray cooling until the actual exhaust gas emission temperature is equal to the set safety set temperature for the high-temperature exhaust gas emission of the aircraft APU, and determining the final value of the water consumption safety coefficient beta;

seventhly, continuously cooling and discharging high-temperature tail gas of the aircraft APU: and calculating the final mass flow of the water for spraying and cooling by using the final value of the water consumption safety coefficient beta in the step six, and continuously spraying and cooling the high-temperature tail gas of the aircraft APU flowing through the initial adjusting pipeline 1 by the plurality of spraying and cooling mechanisms according to the final mass flow of the water for spraying and cooling until the aircraft APU is closed.

In the embodiment, the water consumption safety coefficient beta is 1.5-2.

In this embodiment, the micro positive pressure index is 10 to 80 Pa.

In this embodiment, the exhaust emission safety set temperatureNot more than 80 ℃; the ultralow temperature set value is not higher than-50 ℃; the set temperature is 10-15 ℃.

In this embodiment, the water supply pipe 5-2 is a water supply pipe having one input pipe and two to four output pipes.

In this embodiment, the first temperature sensor 11-1, the second temperature sensor 11-2, the third temperature sensor 11-3, the fourth temperature sensor 11-4, the fifth temperature sensor 11-5 and the sixth temperature sensor 11-6 are arranged at a position of every 1/6 radius widths and 60 degrees of turning angles in the radius direction of the pipeline with the central point of the pipeline as a starting point.

When the system is used, the temperature in the laboratory is adjusted to reach the ultralow temperature set value, the extreme environment is simulated, whether the indoor environment is balanced under the driving condition of the APU is detected by utilizing the temperature sensor of the exhaust port in the laboratory, the temperature sensor of the environment in the laboratory and the pressure sensor of the environment in the laboratory, and then the type of the fan meeting the requirement is selected, so that the stability of the temperature and the pressure in the laboratory is ensured, and the safety of an airplane and a tester is ensured; the electric tracing band has a temperature-controllable heating function, so that the surface temperature of the water supply pipe can be maintained in a set temperature range, the electric tracing band can be automatically switched off when the temperature reaches the set temperature, and the heating function can be switched on again when the temperature is lower than the set temperature, so that the heating temperature of the pipeline is ensured, the phenomenon that the heat-preservation cotton is burnt or even the electric tracing band is short-circuited and burnt due to overhigh local temperature caused by the traditional electric heating temperature-uncontrollable mode can be prevented, and the aim of spraying and cooling the high-temperature tail gas in the pipeline in the ultralow temperature environment is fulfilled; confirm the tail gas volume that initial adjustment pipeline can hold and then decide the water spray volume that sprays the cooling mechanism through initial adjustment pipeline length, still have stability under the ultra-low temperature environment in the laboratory, guarantee the simulation of extreme climate in the laboratory.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.