An experimental device and method for online regulation of a combustion environment

Abstract

The application provides a test device and a regulating method for regulating combustion environment online. The gas in the test box can be sucked into the combustion chamber of the engine sample, one end of the exhaust pipe in the test box is connected with the exhaust port of the engine sample and the other end extends to outside of the test box, the exhaust gas generated by the sample during operation is independently discharged to outside of the test box through the exhaust pipe, and the air supply system connected with the air inlet of the test box is used for regulating the oxygen concentration in the gas entering the test box. The regulating method comprises the following steps: when the measured oxygen concentration is higher than the set value, the control valve on the water supply pipe is opened in batches, the oxygen concentration in the gas flowing through the heating pipe is detected, and the measured oxygen concentration is equal to the set value. The application can not only accurately and quickly regulate the combustion environment in the test box under the condition of meeting the requirement of large gas consumption, but also ensure that the composition uniformity and proportion of the gas entering the combustion space meet the requirements and can continuously carry out the environmental test.

Description

Technical Field

[0001] This invention relates to the field of environmental testing technology, specifically to a test apparatus and method for online control of the combustion environment. Background Technology

[0002] When evaluating the performance of a specific engine model, environmental tests need to be conducted under specific gradient oxygen content (including percentages of 12%, 14%, 15%, 17%, 19%, 20%, 21%, 22%, and 24%).

[0003] A domestic power research institute has developed a combustion chamber capable of regulating the gas environment (document CN113588864A). Through its chamber design, a relatively closed combustion environment can be achieved. The top serves as the exhaust port, and a mixture of nitrogen and oxygen is injected from bottom to top. Before the combustion test, the gas inside the chamber can be completely replaced to ensure the gas environment meets the test requirements. In this design, the required combustion gas ratio is supplied through nitrogen and oxygen cylinders. However, if used to supply the gas required for engine testing, under continuous testing conditions, the high-pressure gas stored in conventional nitrogen and oxygen cylinders can only meet the gas supply requirements for a short time (less than one hour), and the uniformity of the gas inside the test chamber cannot be guaranteed (because a single gas entering the chamber may be directly sucked in and used before being fully mixed), leading to difficulties in conducting related tests. Even with multiple sets of gas cylinders, it is necessary to periodically connect different cylinders, which is very cumbersome. Furthermore, in essence, it can only achieve non-continuous testing.

[0004] In the prior art, document CN108169407A discloses a controllable gas environment and a vertical combustion characteristic experimental device with a sidewall structure, including an experimental platform, an analysis and control cabinet, a combustible gas storage cylinder group and a vacuum pump. The experimental platform includes a combustion chamber, a fixing device for a variable sidewall structure, a gas homogenization device, a heat flow sensor, a linear ignition device and a flue gas collection device. This scheme still uses a combustible gas storage cylinder group to supply the required gas, which is not conducive to continuous combustion experiments.

[0005] More importantly, existing test devices capable of adjusting the combustion environment cannot implement precise and rapid control while meeting the requirement of high gas consumption (gas consumption per unit fuel not less than 14.7 liters), and it is also difficult to ensure that the gas composition entering the combustion space meets the requirements. Summary of the Invention

[0006] In order to solve the technical problems mentioned in the background art, the present invention aims to provide an experimental device and method for online control of the combustion environment.

[0007] The present invention adopts the following technical solution.

[0008] An online combustion environment control test device includes a test chamber with a pressure relief hole and a sample placement rack inside the test chamber. Gas inside the test chamber can be drawn into the combustion chamber of an engine sample. An exhaust pipe inside the test chamber is connected at one end to the exhaust port of the engine sample and extends to the outside of the test chamber at the other end. The exhaust gas generated by the engine sample during operation is independently discharged to the outside of the test chamber through the exhaust pipe. The air inlet of the test chamber is connected to an air supply system, which is used to control the oxygen concentration in the gas entering the test chamber.

[0009] In this invention, the air supply system includes an air compressor, the air outlet of which is connected to a rigid pipe. Several water curtains / films are arranged at intervals inside the rigid pipe. The gas entering the rigid pipe passes through all the water curtains / films in sequence and continues to flow forward. The rigid pipe is connected to an evaporator, which is connected to a heating tube. The gas flowing out of the rigid pipe is dehumidified by the evaporator and then enters the heating tube to be heated to the target temperature. The heating tube is connected to a test chamber through a flexible pipe, and an oxygen concentration sensor is installed inside the heating tube.

[0010] In order to more efficiently control the combustion environment, several flat-hole nozzles are installed at the top of the rigid pipe. The nozzle orifices are located inside the rigid pipe and are arranged downwards. The diameter of the water film sprayed through the flat-hole nozzle is not less than the diameter of the rigid pipe. Each flat-hole nozzle is equipped with a control valve on its water supply pipe.

[0011] In order to better control the combustion environment, in one design, the flat nozzle is arranged at an angle downward and toward the intake side, so that the water film sprayed by the flat nozzle forms an angle of 8-12° with the vertical plane.

[0012] In another embodiment, gauze is placed inside a rigid pipe near a flat-hole nozzle, and the water sprayed from the flat-hole nozzle flows downward along the gauze to form a water curtain.

[0013] As a preferred option, the spacing between adjacent water curtains / water films should be no less than 200mm.

[0014] As a preferred embodiment, an axially arranged strip groove is provided along the low point of the rigid pipe, through which water inside the rigid pipe is discharged.

[0015] Furthermore, an oxygen supply pipe is installed inside the final stage water curtain / water film. The oxygen supply pipe is connected to a pure oxygen supply system. The nozzles of the oxygen supply pipe are arranged facing the air inlet side, and a control valve is installed on the oxygen supply pipe.

[0016] A method for controlling the combustion environment using the aforementioned test apparatus, comprising the following steps:

[0017] Step 1: Place the engine sample on the sample rack, close the test chamber door, and open the pressure relief vent.

[0018] Step 2: Turn on the air supply system to allow the gas processed by the air supply system to enter the test chamber;

[0019] Step 3: Detect the oxygen concentration M in the gas flowing through the heating tube;

[0020] Step 4: When the measured oxygen concentration M is higher than the set value M0, open the control valve on the water supply pipe in batches, and after each opening of the control valve, detect the oxygen concentration M in the gas flowing through the heating pipe until the measured oxygen concentration M is equal to the set value M0.

[0021] A method for controlling the combustion environment using the aforementioned test apparatus, comprising the following steps:

[0022] Step 11: Place the engine sample on the sample rack, close the test chamber door, and open the pressure relief vent.

[0023] Step 12: Turn on the air supply system to allow the gas processed by the air supply system to enter the test chamber;

[0024] Step 13: Detect the oxygen concentration M in the gas flowing through the heating tube;

[0025] Step 14: When the measured oxygen concentration M is lower than the set value M0, the control valve on the water supply pipe is closed in batches, and the oxygen concentration M in the gas flowing through the heating pipe is detected two minutes after each closure of the control valve, until the measured oxygen concentration M is equal to the set value M0.

[0026] Step 15: If the oxygen concentration set value M0 is greater than the specific gravity of oxygen in the air, then directly close all control valves on the water supply pipe, simultaneously close the evaporator, and gradually open the control valves on the oxygen supply pipe until the measured oxygen concentration M equals the set value M0.

[0027] Beneficial effects: The solution of this invention not only enables precise and rapid control of the combustion environment within the test chamber while meeting high gas consumption requirements, with the oxygen content control gradient in the combustion environment accurate to 30-50 ml, fully meeting the requirement of a 1% oxygen content ratio for the experiment, but also ensures the uniformity and proportion of the gas composition entering the combustion space, and allows for continuous environmental testing. Furthermore, this test device primarily uses air as the gas source, significantly simplifying the operation process and reducing the cost and difficulty of the experiment. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the experimental device for online control of the combustion environment in the embodiment;

[0029] Figure 2 This is a schematic diagram of the rigid pipe cross-section of the test device in the embodiment. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the present invention,

[0031] Example

[0032] Combination Figure 1 and Figure 2 As shown, an online combustion environment control test device includes a test chamber 16, which is a simple and closable box. The test chamber 16 has a pressure relief hole and a sample rack inside. Gas inside the test chamber 16 can be drawn into the combustion chamber of an engine sample. An exhaust pipe inside the test chamber 16 is connected at one end to the exhaust port of the engine sample and extends to the outside of the test chamber 16. The exhaust gas generated when the engine sample is working is independently discharged to the outside of the test chamber 16 through the exhaust pipe. The air inlet of the test chamber 16 is connected to an air supply system, which is used at least to control the oxygen concentration in the gas entering the test chamber 16.

[0033] In this embodiment, the air supply system includes an air compressor 10. The gas pressure at the outlet of the air compressor 10 is between 0.4 and 0.6 MPa. The gas outlet of the air compressor 10 is connected to a rigid pipe 11. Several water curtains / water films (referred to as 13 here) are arranged at intervals inside the rigid pipe 11. The spacing between adjacent water curtains / water films is 250 mm. A baffle 17 is provided on the top wall of the inner cavity of the rigid pipe 11 and between adjacent water curtains / water films. (Because the root of the flat nozzle 12 has a small dead zone 21 without water film, the baffle 17 can prevent pressurized gas from interfering with / tearing open the water curtains / water films.) At the root of the water film, thus preventing the formation of the water curtain / water film or even destroying the water film, the baffle plate 17 is an arc-shaped plate adapted to the inner cavity of the rigid pipe 11. The height of the baffle plate 17 is no more than 1 / 2 of the inner diameter of the rigid pipe 11. The gas entering the rigid pipe 11 passes through all the water curtains / water films in sequence and continues to flow forward. The rigid pipe 11 is connected to the evaporator 14, and the evaporator 14 is connected to the heating tube 15. The gas flowing out of the rigid pipe 11 is dehumidified by the evaporator 14 and then enters the heating tube 15 to be heated to the target temperature. The heating tube 15 is connected to the test chamber 16 through a flexible pipe. An oxygen concentration sensor is installed in the heating tube 15.

[0034] In this embodiment, several flat-hole nozzles 12 are installed at the top of the rigid pipe 11. The nozzle orifices of the flat-hole nozzles 12 are located inside the rigid pipe 11 and arranged downwards. The diameter of the water film sprayed through the flat-hole nozzles 12 is not less than the diameter of the inner cavity of the rigid pipe 11. A control valve is installed on the water supply pipe of each flat-hole nozzle 12. The flat-hole nozzles 12 are arranged obliquely downwards and towards the air inlet side so that the water film sprayed by the flat-hole nozzles forms a 10° angle with the vertical plane. In another embodiment, gauze is installed inside the rigid pipe 11 and near the flat-hole nozzles 12. The water sprayed by the flat-hole nozzles 12 flows downwards along the gauze to form a water curtain.

[0035] Among them, an axially arranged strip groove is provided along the low point of the rigid pipe 11, and the water in the rigid pipe 11 is discharged through the strip groove.

[0036] An oxygen supply pipe 20 is installed inside the final stage water curtain / water film. The oxygen supply pipe 20 is connected to a pure oxygen supply system 19. The nozzles of the oxygen supply pipe 20 are arranged facing the air inlet side. A control valve is installed on the oxygen supply pipe.

[0037] One method for controlling the combustion environment using the test apparatus in this embodiment includes the following steps:

[0038] Step 1: Place the engine sample on the sample rack, close the door of test chamber 16, and open the pressure relief hole;

[0039] Step 2: Turn on the air supply system (in this state, some control valves on the water supply pipe can be pre-set to open) to allow the gas processed by the air supply system to enter the test chamber 16.

[0040] Step 3: Detect the oxygen concentration M in the gas flowing through the heating tube 15;

[0041] Step 4: When the measured oxygen concentration M is higher than the set value M0 (M0 is less than 21% of the oxygen content in the air), open the control valve on the water supply pipe in batches (open 3 control valves in each batch), and after each control valve is opened, detect the oxygen concentration M in the gas flowing through the heating pipe 15 two minutes later, until the measured oxygen concentration M is equal to the set value M0.

[0042] A second method for controlling the combustion environment using the test apparatus in this embodiment includes the following steps:

[0043] Step 11: Place the engine sample on the sample rack, close the door of the test chamber 16, and open the pressure relief hole;

[0044] Step 12: Turn on the air supply system to allow the gas processed by the air supply system to enter the test chamber 16;

[0045] Step 13: Detect the oxygen concentration M in the gas flowing through the heating tube 15;

[0046] Step 14: When the measured oxygen concentration M is lower than the set value M0, the control valve on the water supply pipe is closed in batches, and two minutes after each closure of the control valve, the oxygen concentration M in the gas flowing through the heating pipe 15 is detected until the measured oxygen concentration M is equal to the set value M0.

[0047] Step 15: If the oxygen concentration set value M0 is greater than the specific gravity of oxygen in the air, then directly close all control valves on the water supply pipe, and at the same time close the evaporator 14, and open the control valves on the oxygen supply pipe one by one until the measured oxygen concentration M is equal to the set value M0.

[0048] During operation, atmospheric air is drawn in and compressed by the air compressor 10 to become pressurized gas. The pressurized gas then enters the rigid pipe 11. Each time the pressurized gas passes through a water curtain / water film, a trace amount of oxygen is absorbed. After the pressurized gas passes through multiple water curtains / water films, the oxygen content in the pressurized gas can be reduced to the target value, while the water containing dissolved oxygen will be discharged through the strip groove. When the oxygen content in the pressurized gas meets the requirements, it will be introduced into the evaporator 14 for dehumidification. The dehumidified gas then enters the heating tube 15 and is heated to the required temperature (e.g., 25°C).

[0049] As a key aspect of this invention, the oxygen content in the gas required for the experiment can be rapidly and online controlled via the air compressor 10, the aforementioned rigid pipe 11 with a specific structure, the water supply system, the evaporator 14, and the heating element 15. This achieves precise and rapid control of the combustion environment within the test chamber while meeting the requirements for high gas consumption. Since approximately 30 mL of oxygen can dissolve in 1 L of water at room temperature and standard atmospheric pressure, and excluding the dissolved oxygen already present in the water, when the inner diameter of the rigid pipe 11 is 200 mm and the thickness of a single water curtain / film is controlled at 2 mm, a single water curtain / film can absorb milliliters of oxygen. Using multiple water curtains / films can absorb 30-50 ml of oxygen, fully meeting the requirement of a 1% oxygen content ratio for the experiment. In application, if a 20% oxygen content requirement is needed, only 100 ml of oxygen per unit volume (1 L) at room temperature and pressure needs to be absorbed. When it is necessary to meet the requirement that the oxygen content in the gas is higher than 21%, it is only necessary to increase the oxygen content per unit volume (1L) at normal temperature and pressure. This can be done by closing the control valves on all water supply pipes and then opening the control valve on the oxygen supply pipe until the measured oxygen concentration equals the set value. In this case, since the added oxygen is mixed at the end of the rigid pipe 11, the gas is fully mixed before entering the test chamber, ensuring the uniformity of the gas composition entering the combustion space.

[0050] As another key point of the present invention, by placing the evaporator 14 and heating tube 15 externally and connecting them in series with the rigid pipe 11, the traditional test chamber layout is completely changed, which enables the test to be carried out smoothly and safely in the test chamber. Moreover, all the gas required for the engine sample test is drawn in from the inner cavity of the test chamber and discharged separately, which can ensure that the uniformity and proportion of the gas composition entering the combustion space meet the requirements.

[0051] The solution of this invention not only enables precise and rapid control of the combustion environment within the test chamber while meeting high gas consumption requirements, but also ensures that the uniformity and proportion of the gas composition entering the combustion space meet the requirements, and allows for continuous environmental testing. Furthermore, this test device primarily uses air as the gas source, significantly simplifying the operation process and reducing the cost and operational difficulty of the test.

Claims

1. A test device for online control of combustion environment, comprising a test chamber, a pressure relief hole provided on the test chamber, and a sample placement rack provided inside the test chamber, characterized in that: The gas inside the test chamber can be drawn into the combustion chamber of the engine sample; an exhaust pipe located inside the test chamber connects one end to the exhaust port of the engine sample and extends the other end outside the test chamber, allowing the exhaust gas generated by the engine sample to be discharged independently outside the test chamber during operation; the air inlet of the test chamber is connected to an air supply system, which is used to regulate the oxygen concentration in the gas entering the test chamber; the air supply system includes an air compressor, the gas outlet of which is connected to a rigid pipe, and several spaced water curtains / films are installed inside the rigid pipe. The gas entering the rigid pipe passes through all the water curtains / films in sequence and continues to flow forward. The rigid pipe is connected to an evaporator, which is connected to a heating element. The gas flowing out of the rigid pipe is dehumidified by the evaporator and then enters the heating element to be heated to the target temperature. The heating element then... The flexible pipe connection test chamber has an oxygen concentration sensor installed inside the heating tube. Several flat-hole nozzles are installed at the top of the rigid pipe, with the nozzle orifices located inside the rigid pipe and facing downwards. The diameter of the water film sprayed through the flat-hole nozzles is not less than the diameter of the rigid pipe's inner cavity. Each flat-hole nozzle has a control valve on its water supply pipe. When the measured oxygen concentration M is higher than the set value M0, the control valves on the water supply pipes are opened in batches. Two minutes after each valve is opened, the oxygen concentration M in the gas flowing through the heating tube is measured until the measured oxygen concentration M equals the set value M0. If the set oxygen concentration M0 is greater than the oxygen concentration in the air, all control valves on the water supply pipes are closed directly, the evaporator is shut off, and the control valves on the oxygen supply pipes are opened in stages until the measured oxygen concentration M equals the set value M0.

2. The experimental apparatus according to claim 1, characterized in that: The flat nozzle is arranged at an angle downwards and toward the air intake side so that the water film sprayed from the flat nozzle forms an angle of 8-12° with the vertical plane.

3. The experimental apparatus according to claim 2, characterized in that: A gauze cloth is placed inside a rigid pipe near a flat-hole nozzle. The water sprayed from the flat-hole nozzle flows downward along the gauze to form a water curtain.

4. The test apparatus according to any one of claims 1-3, characterized in that: The distance between adjacent water curtains / water films shall not be less than 200mm.

5. The test apparatus according to claim 4, characterized in that: An axially arranged strip groove is provided along the lowest point of the rigid pipe, through which water inside the rigid pipe is discharged.

6. The test apparatus according to claim 5, characterized in that: An oxygen supply pipe is installed inside the final stage water curtain / water film. The oxygen supply pipe is connected to a pure oxygen supply system. The nozzles of the oxygen supply pipe are arranged facing the air inlet side. A control valve is installed on the oxygen supply pipe.

7. A method for controlling the combustion environment using the test apparatus described in claim 5 or 6, characterized in that the steps include... include: Step 1: Place the engine sample on the sample rack, close the test chamber door, and open the pressure relief vent. Step 2: Turn on the air supply system to allow the gas processed by the air supply system to enter the test chamber; Step 3: Detect the oxygen concentration M in the gas flowing through the heating tube; Step 4: When the measured oxygen concentration M is higher than the set value M0, open the control valve on the water supply pipe in batches, and after each opening of the control valve, detect the oxygen concentration M in the gas flowing through the heating pipe until the measured oxygen concentration M is equal to the set value M0.

8. A method for controlling the combustion environment using the test apparatus of claim 6, characterized in that the steps include... include: Step 11: Place the engine sample on the sample rack, close the test chamber door, and open the pressure relief vent. Step 12: Turn on the air supply system to allow the gas processed by the air supply system to enter the test chamber; Step 13: Detect the oxygen concentration M in the gas flowing through the heating tube; Step 14: When the measured oxygen concentration M is lower than the set value M0, the control valve on the water supply pipe is closed in batches, and the oxygen concentration M in the gas flowing through the heating pipe is detected two minutes after each closure of the control valve, until the measured oxygen concentration M is equal to the set value M0. Step 15: If the oxygen concentration setpoint M0 is greater than the oxygen concentration in the air, then directly close all control valves on the water supply pipe, simultaneously close the evaporator, and gradually open the control valves on the oxygen supply pipe until the measured oxygen concentration M equals the setpoint M0.

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