Method for optimizing combustion process of ammonia / diesel dual-fuel engine based on CFD simulation and Taguchi method

Abstract

An ammonia / diesel dual-fuel engine combustion process optimization method based on CFD simulation and a Taguchi method belongs to the technical field of internal combustion engines, and comprises the following steps: parameterizing a combustion chamber structure of a dual-fuel engine, obtaining characteristic points of the combustion chamber, carrying out single-factor influence rule analysis on each parameter, determining a combustion system parameter value range, and determining a combustion system parameter value range; selecting a proper level number, designing an orthogonal table according to a Taguchi method, and formulating a test scheme; establishing a corresponding engine model in CFD simulation software by using the designed orthogonal table, carrying out analogue simulation, and obtaining emission and thermal efficiency data under different parameter combinations; extracting emission and thermal efficiency data in a simulation result, calculating a signal-to-noise ratio of each factor under each level by using a signal-to-noise ratio calculation formula, and determining an optimal parameter combination; through range analysis, the influence degree of each factor on the performance index is evaluated, main influence factors are identified, and the optimization direction is defined; and adjusting and optimizing parameter setting according to an analysis result, and verifying the effectiveness of the optimization scheme by using CFD simulation software again. The problems that an ammonia / diesel oil dual-fuel engine is low in combustion efficiency and complex in combustion parameter optimization process are solved, and support can be provided for development of the high-efficiency dual-fuel engine.

Description

Technical Field

[0001] The present invention relates to a combustion process optimization method in the technical field of internal combustion engines, in particular to an ammonia / diesel dual-fuel engine combustion process optimization method based on CFD simulation and Taguchi method capable of realizing dual-fuel engine parameters. Background Art

[0002] With the increasing awareness of global environmental protection and the increasingly severe energy crisis, the carbon emission problem caused by the widespread use of traditional fossil fuels has become increasingly prominent. According to statistics, since the industrial revolution, the concentration of carbon dioxide (CO2) in the atmosphere has increased significantly, and global warming and extreme weather events have occurred frequently, seriously threatening human survival and development. Therefore, the development of clean, low-carbon or even zero-carbon emission alternative fuels has become an important direction for future energy development.

[0003] In recent years, ammonia, as a hydrogen-rich fuel, has attracted widespread attention due to its advantages such as zero carbon emissions and easy storage and transportation. Unlike traditional hydrocarbon fuels, ammonia does not directly produce CO2 during combustion. Therefore, in the context of global carbon emission reduction, ammonia is considered to be an alternative fuel with great potential, especially in the field of internal combustion engines. The dual-fuel engine of ammonia and diesel combines ammonia with diesel and ignites ammonia through diesel injection, thereby realizing the application of ammonia fuel on the existing internal combustion engine platform. However, ammonia as a fuel still faces many challenges, including slow combustion speed, high ignition temperature, and poor combustion stability, which makes it difficult to use ammonia efficiently in conventional internal combustion engines. Therefore, improving the combustion efficiency of ammonia-diesel dual-fuel engines and developing a combustion process optimization method for ammonia-diesel dual-fuel engines with strong operability and low experimental cost are the current research focuses. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned technologies, the present invention proposes a combustion process optimization method for an ammonia / diesel dual-fuel engine based on CFD simulation and Taguchi method, which captures the relationship between speed and torque at different times under transient operating conditions of the diesel engine to achieve combustion process optimization.

[0005] In order to solve the above technical problems, the present invention includes the following steps: Step 1, parameterize the combustion chamber structure of the dual-fuel engine, obtain the characteristic points of the combustion chamber, carry out the single factor influence law analysis of each parameter, determine the type and value range of the combustion system parameters, select the appropriate number of levels, and design the orthogonal table according to the Taguchi method to formulate the test plan; Step 2, use the designed orthogonal table to establish the corresponding engine model in the CFD simulation software, carry out simulation simulation, and obtain the emission, thermal efficiency and other performance data under different parameter combinations; Step 3, extract the emission and thermal efficiency data in the simulation results as the input data for signal-to-noise ratio analysis. Use the signal-to-noise ratio calculation formula to perform signal-to-noise ratio analysis on the data, calculate the signal-to-noise ratio of each factor at each level, and determine the optimal parameter combination; Step 4, through the range analysis, evaluate the influence of each factor on the performance index, identify the main influencing factors, and clarify the optimization direction; Step 5, adjust and optimize the parameter settings according to the analysis results, and use the CFD simulation software again to verify the effectiveness of the optimization plan.

[0006] Furthermore, in the present invention, the calculation formula of the signal-to-noise ratio with the expected large characteristic is:

[0007]

[0008] Where: is the signal-to-noise ratio, n is the total number of test samples, y i is the actual value;

[0009] Furthermore, in the present invention, the range analysis calculation formula is:

[0010]

[0011] Where: represents the average response value of the factor at the i-th level, Y ij represents the j-th test result of the factor at the i-th level, n i It represents the number of trials for this factor at the i-th level.

[0012] Compared with the prior art, the invention has the following beneficial effects: the invention realizes the optimization of the combustion process of the ammonia-diesel dual-fuel engine based on CFD simulation and Taguchi method. The method can improve the combustion performance of the ammonia-diesel dual-fuel engine, optimize the ammonia-diesel-air mixing process, improve the economy and feasibility of the combustion system optimization process, and provide a basis for the development of high-efficiency dual-fuel engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure is a flow chart of the optimization method of the present invention. DETAILED DESCRIPTION

[0014] In order to make the contents of the present invention easier to understand, the technical scheme of the present invention is further explained below in conjunction with specific embodiments. The examples are only used to illustrate the present invention, but the present invention is not limited to the contents. The operation methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or according to the product instructions. The chemical reagents without specifying the manufacturer are all conventional drugs that comply with national standards and can be purchased on the market.

[0015] Example

[0016] Specific implementation examples include Figure 1 First, the combustion chamber structure of the dual-fuel engine is parameterized to obtain the characteristic points of the combustion chamber, and the single factor influence law analysis of each parameter is carried out to determine the type and value range of the combustion system parameters, select the appropriate number of levels, and design the orthogonal table according to the Taguchi method to formulate the test plan;

[0017] Secondly, using the designed orthogonal table, the corresponding engine model is established in the CFD simulation software, and simulation is carried out to obtain performance data such as emissions and thermal efficiency under different parameter combinations.

[0018] Then, the emission and thermal efficiency data in the simulation results are extracted as the input data for the signal-to-noise ratio analysis. The signal-to-noise ratio calculation formula is used to perform signal-to-noise ratio analysis on the data, calculate the signal-to-noise ratio of each factor at each level, and determine the optimal parameter combination. According to the Wangda characteristics, the signal-to-noise ratio calculation formula is:

[0019]

[0020] Where: is the signal-to-noise ratio, n is the total number of test samples, y i is the actual value;

[0021] Then, through range analysis, evaluate the impact of each factor on performance indicators, identify the main influencing factors, and clarify the optimization direction.

[0022] Among them, the calculation formula for range analysis is:

[0023]

[0024] Where: represents the average response value of the factor at the i-th level, Y ij represents the j-th test result of the factor at the i-th level, n i It represents the number of trials for this factor at the i-th level.

[0025] Finally, the parameter settings were adjusted and optimized based on the analysis results, and the CFD simulation software was used again to verify the effectiveness of the optimization solution.

[0026] Taking the specific test results of an ammonia-diesel dual-fuel engine as an example, the combustion system parameters are selected as injection timing, injection pressure and combustion chamber throat diameter, and the single factor influence law analysis of each parameter is carried out to determine the parameter value range. Each parameter is selected at three levels, and the corresponding table of combustion parameter control factors is obtained. Based on this table, a three-factor three-level L 9 (3 3 ) orthogonal table, as shown in Table 1; based on the orthogonal table, the signal-to-noise ratio analysis is carried out to obtain a set of optimal combustion system parameters

[0027] Table 1L 9 (3 3 )Orthogonal array

[0028]

[0029] After that, the Converge simulation software was used to verify the effectiveness of the optimization scheme. After applying the prediction method of the present invention, it can be seen from Table 1 that the combustion process optimization method of the ammonia-diesel dual-fuel engine based on CFD simulation and Taguchi method can effectively improve the performance parameters such as ammonia combustion efficiency, effective power, and mean indicated pressure. The results show that the combustion process optimization method of the ammonia-diesel dual-fuel engine based on CFD simulation and Taguchi method only uses 9 sets of test data, which greatly reduces the test cost and improves the optimization efficiency. The thermal efficiency after optimization is increased by 3.89%, achieving the performance improvement of the ammonia-diesel dual-fuel engine, as shown in Table 2.

[0030] Table 2 Comparison of performance parameters before and after optimization

[0031]

[0032]

[0033] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for optimizing the combustion process of an ammonia / diesel dual-fuel engine based on CFD simulation and Taguchi method, characterized in that: The following steps are involved: Step 1: Parameterize the combustion chamber structure of the dual-fuel engine, obtain the characteristic points of the combustion chamber, conduct single factor influence law analysis of each parameter, determine the type and value range of the combustion system parameters, select the appropriate number of levels, and design the orthogonal table according to the Taguchi method to formulate the test plan; Step 2: Use the designed orthogonal table to build a corresponding engine model in the CFD simulation software, carry out simulation, and obtain emission and thermal efficiency data under different parameter combinations; Step 3: Extract the emission and thermal efficiency data from the simulation results as input data for signal-to-noise ratio analysis. Use the signal-to-noise ratio calculation formula to perform signal-to-noise ratio analysis on the data, calculate the signal-to-noise ratio of each factor at each level, and determine the optimal parameter combination; Step 4: Evaluate the influence of each factor on the performance index through range analysis, identify the main influencing factors, and clarify the optimization direction; Step 5: Adjust and optimize the parameter settings based on the analysis results, and use CFD simulation software again to verify the effectiveness of the optimization solution.

2. The method for optimizing the combustion process of an ammonia / diesel dual-fuel engine based on CFD simulation and Taguchi method according to claim 1, characterized in that In step 3, according to the Wangda characteristic, the signal-to-noise ratio calculation formula is: Where: is the signal-to-noise ratio, n is the total number of test samples, y i is the actual value.

3. The method for optimizing the combustion process of an ammonia / diesel dual-fuel engine based on CFD simulation and Taguchi method according to claim 1, characterized in that In step 4, the range analysis calculation formula is: Where: represents the average response value of the factor at the i-th level, Y ij represents the j-th test result of the factor at the i-th level, n i It represents the number of trials for this factor at the i-th level.

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