Evaluation method and system for representing soot characteristics of fuel for complex fuel and medium

Abstract

The invention discloses a method and a system for evaluating soot characteristics of characterization fuels for complex fuels and a medium, the evaluation method comprises the following steps: preparing carbon-based fuels, and preparing characterization fuels with different components of the carbon-based fuels; building a laminar flow diffusion flame system to obtain laminar flow diffusion flame; after the flame is stable, carrying out a PAHs-LIF test; a Soot-LII test is carried out; and step 5, integrating the comparison results of the PAHs-LIF and the Soot-LII, and determining the optimal characterization fuel component capable of characterizing the soot characteristics of the carbon-based fuel in the whole combustion process. The method can explain whether the combustion chemical effect of the fuel can copy the whole process behavior of the real fuel combustion process from the soot precursor to the final soot particles, which is crucial for combustion modeling, emission prediction and optimization design of a power device.

Description

Technical Field

[0001] The present invention belongs to the field of data processing, and in particular relates to a method, system and medium for evaluating fuel soot characteristics for complex fuels. Background Art

[0002] The actual composition of carbon-based fuels for transportation, such as gasoline, diesel, biodiesel, kerosene, and jet fuel, is very complex and contains a variety of hydrocarbons and other compounds. Due to this complexity, it is extremely difficult to construct chemical kinetic mechanisms including all components in CFD simulations necessary for the optimal design of power plants (such as internal combustion engines, aircraft engines, and gas turbines) under the current level of computer performance and knowledge of fuel chemical kinetics. Therefore, using fuels with fewer pure components to characterize the key physical and chemical properties of complex fuels has become an effective solution. Since it is relatively simple to characterize fuel components, it is easier to construct chemical kinetic mechanisms and perform combustion simulations and emission predictions. The prediction of soot particle emissions is the most complex and challenging of all emission predictions due to its association with fuel chemistry, fuel composition, and soot particle physical models. For the various existing characterized fuels, it is necessary to understand which one is the best for predicting the soot properties of actual fuels. Summary of the invention

[0003] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a method, system and medium for evaluating the carbon soot characteristics of complex fuels.

[0004] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0005] A method for evaluating fuel soot characteristics for complex fuels, the evaluation method comprising the following steps:

[0006] Step 1: Prepare carbon-based fuel and configure the characterization fuel of its different components;

[0007] Step 2: Build a laminar diffusion flame system to obtain a laminar diffusion flame;

[0008] Step 3: After the flame is stabilized, the PAHs-LIF test is performed, the measured LIF signal peak is normalized with the carbon-based fuel as the standard, and then the LIF signal peak and distribution of various characterization fuels and carbon-based fuels are compared;

[0009] Step 4: Perform Soot-LII test, normalize the measured LII signal peak value with carbon-based fuel as the standard, and then compare the LII signal peak value and distribution of various characterization fuels and carbon-based fuels;

[0010] Step 5: Based on the comparison results of PAHs-LIF and Soot-LII, determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

[0011] Further, the laminar diffusion flame system comprises:

[0012] a burner body for simultaneously providing fuel vapor and co-flow air;

[0013] A liquid fuel supply pump, used to supply liquid fuel to the evaporator at a set flow rate;

[0014] An evaporator is used to mix the carrier nitrogen gas and the liquid fuel according to a set flow rate and heat them to completely volatilize so as to enter the burner body;

[0015] A flow controller for controlling the flow of carrier nitrogen and co-flow air;

[0016] An air compressor is used to provide co-flow air.

[0017] Furthermore, the burner body is composed of two concentric metal tubes, the inner tube is used to provide fuel vapor, the outer tube is used to provide co-flow air, and glass beads and sintered metal porous plates are filled between the inner and outer tubes to ensure uniformity of air flow.

[0018] Furthermore, PAHs-LIF testing includes:

[0019] A sheet laser is used to pass through the center of the flame to excite the fluorescence signals of PAHs in the flame;

[0020] The two-dimensional fluorescence signal was collected using a camera combined with a bandpass filter.

[0021] Furthermore, a laser beam with a wavelength of 266nm and suitable energy is used to form a sheet laser through a sheet light system; the camera gate width is 30ns, and four narrow bandpass filters with different central wavelengths of 320, 360, 400 and 450nm are installed in front of the camera lens to distinguish the relative sizes of PAHs.

[0022] Further, the Soot-LII test includes:

[0023] Use a sheet of laser to pass through the center of the flame to excite the incandescent signal of soot particles;

[0024] The two-dimensional incandescent signal is collected using a camera combined with a bandpass filter.

[0025] Furthermore, a laser beam with a wavelength of 532nm or 1064nm and suitable energy is used to form a sheet laser through a polarization system; the camera gate width is 20ns, and four narrow bandpass filters with different central wavelengths of 320, 360, 400 and 450nm are installed in front of the camera lens to distinguish the relative sizes of PAHs; the delay time of the camera is set to 30ns after the arrival of the sheet laser.

[0026] Furthermore, the carbon-based fuel is one of gasoline, diesel, biodiesel, kerosene, and aviation kerosene.

[0027] The present invention also provides a fuel soot characteristic evaluation system for complex fuels, comprising a flame control module for controlling a laminar diffusion flame system to obtain a laminar diffusion flame;

[0028] The first test module is used to perform a PAHs-LIF test after the flame is stabilized, normalize the measured LIF signal peak value with the carbon-based fuel as the standard, and then compare the LIF signal peak values ​​and distributions of various characterizing fuels and carbon-based fuels;

[0029] The second test module is used to perform Soot-LII test, normalize the measured LII signal peak value with carbon-based fuel as the standard, and then compare the LII signal peak value and distribution of various characterization fuels and carbon-based fuels;

[0030] The comparative analysis module is used to integrate the comparison results of PAHs-LIF and Soot-LII to determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

[0031] The present invention also provides a computer storage medium having a computer program stored thereon, characterized in that the above-mentioned evaluation method is implemented when the computer program is executed.

[0032] The beneficial effects of the present invention are:

[0033] From the perspective of fuel chemistry, this invention proposes a method for evaluating the full characteristics of soot for complex carbon-based fuels based on the excitation signals of aromatic hydrocarbons (soot precursors) with different ring numbers measured by laser-induced fluorescence (PAHs-LIF) and the soot particle excitation signals (Soot-LII) measured by laser-induced incandescence (LAI) in a simple atmospheric environment such as laminar diffusion flame. This method can illustrate whether these combustion chemical effects that characterize the fuel itself can replicate the full process behavior of the real fuel combustion process from soot precursors to final soot particles, which is crucial for combustion modeling, emission prediction and optimization design of power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 is a flow chart of the evaluation method of the present invention;

[0036] Figure 2 It is a schematic diagram of the comparison of normalized peak signals of aromatic hydrocarbons (carbon soot precursors) with different ring numbers between gasoline and various characterization fuels;

[0037] Figure 3 It is a comparative schematic diagram of PAHs-LIF signals detected at 450nm for gasoline and characterized fuel;

[0038] Figure 4 It is a schematic diagram of the comparison of the soot particle Soot-LII signal between gasoline and the representative fuel;

[0039] Figure 5 It is a structural block diagram of the evaluation system of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 A method for evaluating fuel soot characteristics for a complex fuel is shown, the evaluation method comprising the following steps:

[0042] Step 1: Prepare the carbon-based fuel and configure the characterization fuel of its different components. The carbon-based fuel is one of gasoline, diesel, biodiesel, kerosene, and aviation kerosene.

[0043] Step 2: Build a laminar diffusion flame system to obtain a laminar diffusion flame.

[0044] As a specific embodiment of the present invention, the laminar diffusion flame system comprises:

[0045] a burner body for simultaneously providing fuel vapor and co-flow air;

[0046] A liquid fuel supply pump, used to supply liquid fuel to the evaporator at a set flow rate;

[0047] The evaporator is used to mix the carrier nitrogen and liquid fuel according to the set flow rate, and heat them through the internal high-temperature spiral tube until they are completely volatilized and enter the burner body;

[0048] A flow controller for controlling the flow of carrier nitrogen and co-flow air;

[0049] An air compressor is used to provide co-flow air.

[0050] As a specific embodiment of the present invention, the burner body is composed of two concentric metal tubes, the inner tube is used to provide fuel vapor, the outer tube is used to provide co-flow air, and glass beads and sintered metal porous plates are filled between the inner tube and the outer tube to ensure the uniformity of air flow. The gas of the evaporator enters the inner tube (fuel tube) of the burner body and then ignites. Under the co-flow protection of the outer tube air (flow rate controlled by a flow controller), a laminar diffusion flame can be obtained.

[0051] Step 3: After the flame is stabilized, the PAHs-LIF test is performed, the measured LIF signal peak is normalized with the carbon-based fuel as the standard, and then the LIF signal peak and distribution of various characterization fuels and carbon-based fuels are compared.

[0052] As a specific embodiment of the present invention, the PAHs-LIF test includes:

[0053] A laser beam with a wavelength of 266nm and appropriate energy is used to form a sheet laser with a thickness of about 0.8mm through a sheet light system, and then the sheet laser passes through the center of the flame to excite the fluorescence signal (LIF signal) of PAHs in the flame. Then, an enhanced camera (ICCD) with a gate width of 30ns is used to collect two-dimensional LIF signals in combination with a bandpass filter. Four narrow bandpass filters with different central wavelengths of 320, 360, 400 and 450nm (FWHM10nm) are installed in front of the camera lens to distinguish the relative size of polycyclic aromatic hydrocarbons PAHs (carbon soot precursors). Among them, the fluorescence signal with a wavelength of 320nm represents single-ring aromatic hydrocarbons, the fluorescence signal with a wavelength of 360nm represents 2-3-ring aromatic hydrocarbons, the fluorescence signal with a wavelength of 400nm represents 3-4-ring aromatic hydrocarbons, and the fluorescence signal with a wavelength of 450nm represents 4-5-ring aromatic hydrocarbons.

[0054] Step 4: Perform Soot-LII test, normalize the measured LII signal peak value with carbon-based fuel as the standard, and then compare the LII signal peak value and distribution of various characterization fuels and carbon-based fuels.

[0055] As a specific embodiment of the present invention, the Soot-LII test includes:

[0056] A laser beam with a wavelength of 532nm or 1064nm and appropriate energy is used to form a sheet laser with a thickness of about 0.8mm through a polarization system, and then the sheet laser passes through the center of the flame to excite the incandescent signal (LII signal) of the soot particles. Then, an enhanced camera (ICCD) with a gate width of 20ns combined with a bandpass filter (central wavelength of about 650nm) is used to collect the two-dimensional LII signal, and the delay time of the ICCD is set to 30ns after the laser arrives (to eliminate fluorescence interference).

[0057] Step 5: Based on the comparison results of PAHs-LIF and Soot-LII, determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

[0058] Examples of evaluation of various gasoline fuel soot particle characteristics are shown in the following table:

[0059] Table 1 Components of various gasoline characterization fuels

[0060]

[0061] In summary Figure 2-Figure 4 According to the evaluation, surrogate 4 can best characterize the gasoline soot characteristics.

[0062] The second aspect of the present invention also provides a fuel soot characteristic evaluation system for complex fuels, comprising:

[0063] A flame control module, used for controlling the laminar diffusion flame system to obtain a laminar diffusion flame;

[0064] The first test module is used to perform PAHs-LIF test after the flame is stabilized, normalize the measured LIF signal peak value with carbon-based fuel as the standard, and then compare the LIF signal peak value and distribution of various characterization fuels and carbon-based fuels.

[0065] The second test module is used to perform the Soot-LII test, normalize the measured LII signal peak value with carbon-based fuel as the standard, and then compare the LII signal peak value and distribution of various characterization fuels and carbon-based fuels.

[0066] The comparative analysis module is used to integrate the comparison results of PAHs-LIF and Soot-LII to determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

[0067] The third aspect of the present invention also provides a computer storage medium, on which a computer program is stored, and the computer program implements the above method when executed. The storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for evaluating fuel soot characteristics for complex fuels, characterized in that: The evaluation method includes the following steps: Step 1: Prepare carbon-based fuel and configure the characterization fuel of its different components; Step 2: Build a laminar diffusion flame system to obtain a laminar diffusion flame; Step 3: After the flame is stabilized, the PAHs-LIF test is performed, the measured LIF signal peak is normalized with the carbon-based fuel as the standard, and then the LIF signal peak and distribution of various characterization fuels and carbon-based fuels are compared; Step 4: Perform Soot-LII test, normalize the measured LII signal peak value with carbon-based fuel as the standard, and then compare the LII signal peak value and distribution of various characterization fuels and carbon-based fuels; Step 5: Based on the comparison results of PAHs-LIF and Soot-LI I, determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

2. The method for evaluating fuel soot characteristics for complex fuels according to claim 1, characterized in that: The laminar diffusion flame system consists of: a burner body for simultaneously providing fuel vapor and co-flow air; A liquid fuel supply pump, used to supply liquid fuel to the evaporator at a set flow rate; An evaporator is used to mix the carrier nitrogen gas and the liquid fuel according to a set flow rate and heat them to completely volatilize so as to enter the burner body; A flow controller for controlling the flow of carrier nitrogen and co-flow air; An air compressor is used to provide co-flow air.

3. The method for evaluating fuel soot characteristics for complex fuels according to claim 2, characterized in that: The burner body is composed of two concentric metal tubes. The inner tube is used to provide fuel vapor, and the outer tube is used to provide co-flow air. Glass beads and sintered metal porous plates are filled between the inner and outer tubes to ensure the uniformity of air flow.

4. The method for evaluating fuel soot characteristics for complex fuels according to claim 1, characterized in that: PAHs-LIF testing includes: A sheet laser is used to pass through the center of the flame to excite the fluorescence signals of PAHs in the flame; The two-dimensional fluorescence signal was collected using a camera combined with a bandpass filter.

5. The method for evaluating fuel soot characteristics for complex fuels according to claim 4, characterized in that: A laser beam with a wavelength of 266nm and appropriate energy is used to form a sheet laser through a sheet light system; the camera gate width is 30ns, and four narrow bandpass filters with different central wavelengths of 320, 360, 400 and 450nm are installed in front of the camera lens to distinguish the relative sizes of PAHs.

6. The method for evaluating fuel soot characteristics for complex fuels according to claim 1, characterized in that: Soot-LI I Test Tests include: Use a sheet of laser to pass through the center of the flame to excite the incandescent signal of soot particles; The two-dimensional incandescent signal is collected using a camera combined with a bandpass filter.

7. The method for evaluating fuel soot characteristics for complex fuels according to claim 6, characterized in that: A laser beam with a wavelength of 532nm or 1064nm and appropriate energy is used to form a sheet laser through a polarization system; the camera gate width is 20ns, and four narrow bandpass filters with different central wavelengths of 320, 360, 400 and 450nm are installed in front of the camera lens to distinguish the relative sizes of PAHs; the delay time of the camera is set to 30ns after the arrival of the sheet laser.

8. A method for evaluating fuel soot characteristics for complex fuels according to any one of claims 1 to 7, characterized in that: The carbon-based fuel is one of gasoline, diesel, biodiesel, kerosene, and aviation kerosene.

9. A fuel soot characteristic evaluation system for complex fuels, characterized by: include A flame control module, used for controlling the laminar diffusion flame system to obtain a laminar diffusion flame; The first test module is used to perform PAHs-LIF test after the flame is stabilized, normalize the measured LIF signal peak value with carbon-based fuel as the standard, and then compare the LIF signal peak value and distribution of various characterization fuels and carbon-based fuels; The second test module is used to perform a Soot-LI I test, normalize the measured LI I signal peak value with carbon-based fuel as the standard, and then compare the LI I signal peak value and distribution of various characterization fuels and carbon-based fuels; The comparative analysis module is used to integrate the comparison results of PAHs-LIF and Soot-LI I to determine the best fuel component that can characterize the soot characteristics of the entire combustion process of carbon-based fuels.

10. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the evaluation method according to any one of claims 1 to 8 is implemented.

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