基于GT-Power的天然气发动机数值模拟与研究

发布时间：2017-12-28 09:04

本文关键词：基于GT-Power的天然气发动机数值模拟与研究　出处：《山东理工大学》2016年硕士论文　论文类型：学位论文

更多相关文章： 天然气发动机 GT-Power DOE 性能优化

【摘要】：天然气作为一种清洁能源具有储存量大、燃烧后有害物质排放少、抗爆性好等特点,是一种较为理想的替代燃料。但是天然气发动机与汽油机和柴油机相比,在动力性和经济性方面有较大的差距,为了改善天然气发动机的动力性和经济性,需要对发动机的参数进行优化。在对天然气发动机参数进行优化时,爆震现象是制约发动机性能提高的重要因素,因此需要对天然气发动机的爆震规律进行研究。本文以某发电用增压天然气发动机模型为基础对天然气发动机的性能和爆震规律进行了研究。主要研究工作包括:(1)利用GT-Power软件建立了某发电用增压天然气发动机仿真模型,通过对试验数据和模拟数据进行对比对模型的精确性进行了验证。(2)利用发动机仿真模型,研究了不同压缩比、点火提前角等参数对天然气发动机动力性、经济性和排放特性及爆震发生时刻、爆震强度、爆震指数的影响规律。(3)利用GT-Power中的DOE(试验设计)模块对天然气发动机性能及其重要参数进行优化,并总结出了预测发动机性能变化的数学公式。通过将天然气发动机仿真模型的模拟结果与试验结果进行对比,对仿真模型的精确性进行了验证。在仿真模型中研究了压缩比、点火提前角等参数对不同负荷下天然气发动机动力性、经济性及排放特性的影响规律,并研究了压缩比、点火提前角等因素对天然气发动机爆震开始时刻、爆震强度及爆震指数的影响规律。结果表明:随着压缩比的不断增加,发动机的爆震可能性不断增大,爆震开始时刻不断提前,爆震强度不断增大;随着点火提前角的增加,发动机的爆震可能性不断增大,爆震开始时刻不断提前,爆震强度有一定程度增大;最后利用DOE(试验设计)技术,以压缩比、点火提前角、进气门开启时刻及排气门开启时刻为影响因素,以发动机的扭矩、燃气消耗率、NOx排放量、CO排放量及HC排放量为目标变量,以气缸爆发压力为约束条件对天然气发动机的性能进行了优化。对发动机的性能进行优化之后,发动机的燃气消耗率最大降低15.3%,扭矩最大提高10.3%,NOx排放量最大降低19.6%;额定功率工况下扭矩提高了10.3%,燃气消耗率降低了5.3%,NOx排放量降低了6.4%,CO排放量降低了3.6%,HC排放量降低了1.9%。
[Abstract]:As a kind of clean energy, natural gas has the characteristics of large storage, less emission of harmful substances after combustion and good antiknock, and it is an ideal alternative fuel. However, compared with gasoline engine and diesel engine, there is a big gap between the natural gas engine and the gasoline engine and the diesel engine. In order to improve the power and economy of the natural gas engine, the parameters of the engine need to be optimized. When optimizing the parameters of natural gas engine, knock is an important factor that restricts the improvement of engine performance. Therefore, it is necessary to study the knock rule of natural gas engine. In this paper, the performance and detonation laws of a natural gas engine are studied on the basis of a turbocharged natural gas engine model for a power generation. The main research work includes: (1) a simulation model of a turbocharged natural gas engine is built by using GT-Power software. The accuracy of the model is verified by comparing the experimental data with the simulated data. (2) by using the engine simulation model, the influence of different compression ratio, ignition advance angle and other parameters on the power performance, economy and emission characteristics, detonation time, detonation strength and knock index of natural gas engine are studied. (3) use GT-Power's DOE module to optimize the performance and important parameters of CNG engine, and summarize the mathematical formula to predict engine performance change. By comparing the simulation results of the natural gas engine simulation model with the test results, the accuracy of the simulation model is verified. In the simulation model of the compression ratio, ignition advance angle and other parameters on the different load of natural gas engine power, economy and emission characteristics were investigated, and the effects of the compression ratio, ignition advance angle and other factors on the influence of natural gas engine knock start time, and knock knock intensity index. The results show that with the increasing of compression ratio, the possibility of increasing the engine knock, knock start time continue to advance, the knock intensity increasing; with the increase of spark advance angle, increasing the possibility of engine knock, knock knock intensity start time continue to advance, to a certain extent increase; finally the use of DOE (design of experiment) technology. The compression ratio, ignition advance angle, intake valve timing and exhaust valve opening time for the influence factors to the torque of the engine, the gas consumption rate, NOx emissions, CO emissions and HC emissions as the target variable, to the cylinder explosion pressure as constraint conditions to optimize the performance of natural gas engine. After the performance of the engine is optimized, the engine gas consumption rate decreased 15.3%, the maximum torque is increased by 10.3%, the NOx emissions decreased 19.6%; rated power under the condition of torque is increased by 10.3%, the gas consumption rate decreased by 5.3%, the NOx emissions decreased 6.4%, the CO emissions decreased 3.6%, the HC emissions decreased 1.9%.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK431

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