A device and test method for measuring the airway spray characteristics of a methanol engine

Abstract

The present invention discloses a device and a test method for measuring the airway spray characteristics of a methanol engine, comprising a support, the support is fixedly connected to a constant volume combustion chamber cavity through a coupling, a wall-impacting plate is arranged inside the constant volume combustion chamber cavity, a transient thermocouple is arranged on the wall-impacting plate, a methanol nozzle is arranged on the top of the constant volume combustion chamber cavity, a fixing clamp is arranged on the methanol nozzle, a bolt is arranged on the fixing clamp, and the methanol nozzle is installed on the top of the constant volume combustion chamber cavity through the fixing clamp and the bolt. The device of the present invention is exquisitely designed and relatively simple in structure, and traditional complex and cumbersome measuring equipment is abandoned. This simplicity not only reduces the manufacturing cost, but also makes the operation process extremely convenient. Users can easily get started to accurately measure the airway spray characteristics of a methanol engine without long-term training or complex settings.

Description

Technical Field

[0001] The invention belongs to the technical field of methanol engines, and in particular, relates to a device and a testing method for measuring airway spray characteristics of a methanol engine. Background Art

[0002] Methanol fuel engine is an internal combustion engine that uses methanol as its main fuel. The current oil resources are very tight. Methanol is a by-product produced in the food and chemical processing process, so its cost is very low and it is suitable as a supplementary alternative energy source. The current methanol engines are mostly 2-4 stroke diesel engine structures.

[0003] The transient heat transfer during the methanol spray impact on the wall will affect the wall oil film formation and methanol evaporation. In each working cycle of the methanol engine, the heat transfer process on the inlet surface undergoes multiple modes such as film evaporation, nucleate boiling, transition boiling and even film boiling. In this process, the surface heat flux density on the inlet surface can reach 2MW / m2. Among various engine products, in the development of methanol engine combustion systems, the phenomenon of methanol spray hitting the wall is inevitable in methanol engines, which will cause an oil film to form on the surface of the intake duct, which will have an adverse effect on the thermal efficiency, combustion effect and emission performance of the methanol engine.

[0004] The existing measurement devices and methods often have problems such as low measurement accuracy and complicated operation, which are difficult to meet the needs of accurately measuring the airway spray characteristics of methanol engines. Summary of the invention

[0005] The present invention provides a device and a testing method for measuring the airway spray characteristics of a methanol engine, which solves the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a device for measuring the airway spray characteristics of a methanol engine, comprising a support, the support is fixedly connected to a constant volume combustion chamber cavity through a connecting shaft, a wall impact plate is arranged inside the constant volume combustion chamber cavity, a transient thermocouple is arranged on the wall impact plate, a methanol nozzle is arranged on the top of the constant volume combustion chamber cavity, a fixing clamp is arranged on the methanol nozzle, a bolt is arranged on the fixing clamp, and the methanol nozzle is installed on the top of the constant volume combustion chamber cavity through the fixing clamp and the bolts.

[0007] Preferably, the methanol nozzle is configured as a single-hole injector with a nozzle diameter of 0.1 mm, the impingement plate is made of titanium alloy, and the impingement plate is arranged directly below the methanol nozzle.

[0008] Preferably, the transient thermocouple is arranged at the center of the wall surface of the impact plate by means of a threaded connection, the temperature measuring surface of the transient thermocouple is parallel to the impact wall surface and is in the same plane, and the diameter of the temperature measuring surface of the transient thermocouple is only set to 2 mm.

[0009] A test method for measuring an airway spray characteristic device of a methanol engine, further comprising a methanol system for providing methanol, and the specific steps are as follows: Step S10, the high-pressure methanol pump in the methanol system is driven by a variable frequency motor to generate the required injection pressure, and the test accuracy of the injection pressure is 0.5 MPa; Step S20, setting the response time of transient thermocouples 1-5 to 20 s, and connecting the transient thermocouples to a data acquisition system, with a sampling frequency set to 20000 Hz; Step S30, under the conditions of a jet pressure of 80 MPa, a wall impact distance of 60 mm and an ambient temperature of 120°C, testing the change in the amount of liquid film attached to the wall of the airway at different temperatures of the wall impact plate; Step S40, under the conditions of the wall impact plate temperature of 175°C, the wall impact distance of 60 mm and the ambient temperature of 120°C, the change of the amount of liquid film attached to the wall of the airway under different injection pressures is tested.

[0010] Preferably, the above test is carried out under normal pressure conditions, the methanol injection duration is 1 ms, each test condition is repeated at least 3 times, and the average value of the test measurement parameters is taken to reduce the test error. The thermocouple response time and test accuracy used to measure the steady-state temperature of the impact wall plate and the ambient temperature are 0.1s and 1°C, respectively.

[0011] Preferably, in step S30, the original airway temperature is 200°C, the FH_OPT1 temperature is 175°C, the SQ_OPT1 temperature is 150°C, and the SQ_OPT0 temperature is 125°C.

[0012] Preferably, in step S40, the original airway injection pressure is 90 MPa and FH_OPT1 is 100 MPa.

[0013] The beneficial effects of adopting the above technical solution are: 1. The device of the present invention is exquisitely designed and relatively simple in structure, and the traditional complicated and cumbersome measuring equipment is abandoned. This simplicity not only reduces the manufacturing cost, but also makes the operation process extremely convenient. Users can easily carry out accurate measurement of the airway spray characteristics of the methanol engine without long-term training or complicated settings. In addition, the device is also highly maintainable. Once a fault occurs or calibration is required, it can be quickly handled, thereby ensuring the continuity and stability of the measurement; Second, by setting up transient thermocouples and titanium alloy wall-impacting plates, this technical solution has achieved a qualitative leap in measurement accuracy and reliability. The transient thermocouple can quickly respond to temperature changes during the spraying process and capture the instantaneous temperature fluctuations when the spray hits the wall, thereby more accurately reflecting the impact characteristics of the spray. The titanium alloy wall-impacting plate, with its excellent high temperature resistance and corrosion resistance, ensures stability and reliability during long-term measurements. The combination of the two makes the measurement results more accurate and reliable, providing strong data support for scientific researchers. 3. The test method adopted in this technical solution is scientific and rigorous, covering the comprehensive measurement of the impact, evaporation and distribution characteristics of methanol spray in the airway. By simulating the actual working conditions of the engine, the spray process is monitored and recorded in real time, which can fully reflect the dynamic change process of the spray in the airway. This comprehensive measurement not only helps scientific researchers to have an in-depth understanding of the impact, evaporation and distribution laws of methanol spray, but also provides a strong basis for the optimization and improvement of engine performance. At the same time, the test method is also highly repeatable and comparable, so that the measurement results under different conditions can be directly compared and analyzed, further improving the efficiency and accuracy of scientific research. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the constant volume combustion chamber cavity of the present invention; Figure 2 It is a schematic diagram of the overall device system of the present invention; Figure 3 It is the change in the amount of liquid film attached to the airway wall at different temperatures; Figure 4 It is the change of the amount of liquid film attached to the airway wall under different injection pressures; in: 1. Support; 2. Constant volume combustion chamber cavity; 3. Impact plate; 4. Transient thermocouple; 5. Methanol nozzle; 6. Fixing clamp; 7. Bolt. DETAILED DESCRIPTION

[0015] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation. Example 1

[0016] Specifically, Figures 1 to 4As shown, a device for measuring the airway spray characteristics of a methanol engine comprises a support 1, wherein the support 1 is fixedly connected to a constant volume combustion chamber cavity 2 via a coupling, wherein an impact wall plate 3 is arranged inside the constant volume combustion chamber cavity 2, wherein a transient thermocouple 4 is arranged on the impact wall plate 3, wherein a methanol nozzle 5 is arranged on the top of the constant volume combustion chamber cavity 2, wherein a fixing clamp 6 is arranged on the methanol nozzle 5, wherein a bolt 7 is arranged on the fixing clamp 6, wherein the methanol nozzle 5 is mounted on the top of the constant volume combustion chamber cavity 2 via the fixing clamp 6 and the bolt 7.

[0017] It should be noted that the constant volume combustion chamber cavity 2 is designed to simulate the engine airway environment, and its internal space accurately simulates the pressure and temperature conditions in the engine airway, thereby ensuring the accuracy and reliability of the measurement results. The function of the wall impact plate 3 is to simulate the engine airway wall, so as to observe and analyze the behavioral characteristics of the methanol spray when it hits the wall. The transient thermocouple 4 can monitor the wall temperature changes in the process of the spray hitting the high-temperature wall in real time, thereby capturing the temperature fluctuations at the moment of spray impact, providing valuable data support for scientific researchers. The methanol nozzle 5 is firmly installed on the top of the cavity by the fixing clamp 6 and the bolt 7 to ensure that no displacement or leakage occurs during the measurement process.

[0018] The methanol nozzle 5 is configured as a single-hole fuel injector with a nozzle diameter of 0.1 mm. The impingement plate 3 is made of titanium alloy. The impingement plate 3 is configured directly below the methanol nozzle 5 .

[0019] It should be noted that the wall plate 3 is made of titanium alloy because titanium alloy has low thermal conductivity and can effectively reduce the influence of heat transfer on the measurement results. At the same time, titanium alloy also has excellent high temperature resistance and corrosion resistance, and can maintain stability and reliability during long-term high temperature measurement. The methanol nozzle 5 is set as a single-hole injector with a nozzle diameter of 0.1mm. This fine nozzle design helps to achieve precise control and measurement of the spray.

[0020] The transient thermocouple 4 is set at the center of the wall surface of the impact plate 3 by threaded connection. The temperature measuring surface of the transient thermocouple 4 is parallel to the impact wall surface 3 and is in the same plane. The diameter of the temperature measuring surface of the transient thermocouple 4 is only set to 2 mm.

[0021] It should be noted that the temperature measuring surface of the transient thermocouple 4 is parallel to the impact wall 3 and is in the same plane. This design ensures that the thermocouple can accurately measure the temperature change when the spray impacts the wall. The diameter of the temperature measuring surface of the transient thermocouple 4 is only set to 2 mm, which has little effect on the spray impact process. Example 2

[0022] Specifically, Figures 2 to 4As shown, a test method for measuring the airway spray characteristics of a methanol engine also includes a methanol system for providing methanol, and the specific steps are as follows: Step S10, the high-pressure methanol pump in the methanol system is driven by a variable frequency motor to generate the required injection pressure, and the test accuracy of the injection pressure is 0.5 MPa; Step S20, setting the response time of transient thermocouples 1-5 to 20 s, and connecting the transient thermocouples to a data acquisition system, with a sampling frequency set to 20000 Hz; Step S30, under the conditions of a jet pressure of 80 MPa, a wall impact distance of 60 mm and an ambient temperature of 120°C, testing the change in the amount of liquid film attached to the wall of the airway at different temperatures of the wall impact plate 3; Step S40, under the conditions of the temperature of the impingement plate 3 being 175°C, the impingement distance being 60 mm and the ambient temperature being 120°C, the variation of the amount of liquid film attached to the wall of the airway under different injection pressures is tested.

[0023] The above tests were carried out under normal pressure conditions. The methanol injection duration was 1ms. Each test condition was repeated at least 3 times, and the average value of the test measurement parameters was taken to reduce the test error. The thermocouple response time and test accuracy used to measure the steady-state temperature of the impact plate and the ambient temperature were 0.1s and 1°C, respectively.

[0024] In step S30, the original airway temperature is 200°C, the FH_OPT1 temperature is 175°C, the SQ_OPT1 temperature is 150°C, and the SQ_OPT0 temperature is 125°C.

[0025] It should be noted that the ordinate is the amount of liquid film attached to the airway wall, in mg; the abscissa is the injection time, in ms; When the spray hits the high-temperature wall with an initial wall temperature range of 125 to 200°C 1-6, as the initial wall temperature increases from 125°C to 200°C, the maximum surface heat flux density and the maximum heat transfer coefficient both increase first and then decrease, and reach the maximum value when the initial wall temperature is about 175°C, and the amount of liquid film attached to the wall in the airway is the smallest; analysis shows that the evaporation of methanol on the high-temperature wall causes bubbles to form continuously on the wall, and the heat transfer mode on the high-temperature wall is transformed from a film evaporation mode to a nucleate boiling mode, and finally to a transition boiling mode, and the maximum surface heat flux density is reached in the transition zone between nucleate boiling and transition boiling.

[0026] In step S40, the original airway injection pressure is 90 MPa and FH_OPT1 is 100 MPa.

[0027] It should be noted that the ordinate is the amount of liquid film attached to the airway wall, in mg; the abscissa is the injection time, in ms; As the injection pressure increases, the heat transfer of the spray hitting the high-temperature wall surface is enhanced. Although increasing the injection pressure will make methanol easier to break and form smaller droplets, and the air entrainment effect will be enhanced, since different injection pressures have the same injection duration in the test, increasing the injection pressure will increase the mass of the sprayed methanol. In summary, higher injection pressure can increase the momentum of the methanol spray, thereby forming a greater impact on the wall surface, increasing the turbulence intensity near the wall surface, and at the same time, it also makes the splashing phenomenon more obvious when the spray hits the wall, reducing the formation of the wall oil film.

[0028] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A device for measuring the airway spray characteristics of a methanol engine, comprising a support (1), characterized in that: The support (1) is fixedly connected to a constant volume combustion chamber cavity (2) via a connecting shaft; a wall collision plate (3) is arranged inside the constant volume combustion chamber cavity (2); a transient thermocouple (4) is arranged on the wall collision plate (3); a methanol nozzle (5) is arranged on the top of the constant volume combustion chamber cavity (2); a fixing clamp (6) is arranged on the methanol nozzle (5); a bolt (7) is arranged on the fixing clamp (6); and the methanol nozzle (5) is mounted on the top of the constant volume combustion chamber cavity (2) via the fixing clamp (6) and the bolt (7).

2. The device for measuring the airway spray characteristics of a methanol engine according to claim 1, characterized in that: The methanol nozzle (5) is configured as a single-hole fuel injector with a nozzle diameter of 0.1 mm. The impingement plate (3) is made of a titanium alloy. The impingement plate (3) is disposed directly below the methanol nozzle (5).

3. The device for measuring the airway spray characteristics of a methanol engine according to claim 1, characterized in that: The transient thermocouple (4) is arranged at the center of the wall surface of the impact plate (3) by means of a threaded connection; the temperature measuring surface of the transient thermocouple (4) is parallel to the impact wall surface (3) and is located in the same plane; the diameter of the temperature measuring surface of the transient thermocouple (4) is only set to 2 mm.

4. A test method for measuring the airway spray characteristics of a methanol engine according to any one of claims 1 to 3, characterized in that: A methanol system for providing methanol is also included, and the specific steps are as follows: Step S10, the high-pressure methanol pump in the methanol system is driven by a variable frequency motor to generate the required injection pressure, and the test accuracy of the injection pressure is 0.5 MPa; Step S20, setting the response time of transient thermocouples 1-5 to 20 s, and connecting the transient thermocouples to a data acquisition system, with a sampling frequency set to 20000 Hz; Step S30, under the conditions of a jet pressure of 80 MPa, a wall impact distance of 60 mm and an ambient temperature of 120° C., testing the change in the amount of liquid film attached to the wall of the airway at different temperatures of the wall impact plate (3); Step S40, under the conditions that the temperature of the impingement plate (3) is 175°C, the impingement distance is 60 mm and the ambient temperature is 120°C, the change in the amount of liquid film attached to the wall of the airway under different injection pressures is tested.

5. The device for measuring the airway spray characteristics of a methanol engine according to claim 4, characterized in that: The above tests were carried out under normal pressure conditions. The methanol injection duration was 1ms. Each test condition was repeated at least 3 times, and the average value of the test measurement parameters was taken to reduce the test error. The thermocouple response time and test accuracy used to measure the steady-state temperature of the impact plate and the ambient temperature were 0.1s and 1°C, respectively.

6. The device for measuring the airway spray characteristics of a methanol engine according to claim 4, characterized in that: In step S30, the original airway temperature is 200°C, the FH_OPT1 temperature is 175°C, the SQ_OPT1 temperature is 150°C, and the SQ_OPT0 temperature is 125°C.

7. The device for measuring the airway spray characteristics of a methanol engine according to claim 2, characterized in that: In step S40, the original airway injection pressure is 90 MPa and FH_OPT1 is 100 MPa.

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