基于朗肯循环的汽油机尾气余热回收模拟与实验研究

发布时间：2018-06-02 14:56

本文选题：余热回收 + 朗肯循环　；参考：《天津大学》2016年硕士论文

【摘要】：发动机尾气能量占燃料燃烧放热总量的35%左右,采用朗肯循环系统回收尾气能量,是实现发动机节能的有效途径。本文针对基于朗肯循环的汽油机尾气余热回收系统开展了理论和实验研究。利用GT-Power建立了汽油机模型,对尾气能量分布和余热利用潜力进行了分析,研究表明尾气带走的热量与汽油机输出功率相当,尾气最大可利用率在46%以上,具有较大的回收潜力。利用汽油机模型模拟了尾气背压对汽油机功率的影响,以指导朗肯循环系统的设计。从系统回收效率以及设备小型化的角度考虑,选择水为朗肯循环工质,并确定了评价系统性能的指标。建立了单阀膨胀机Matlab/Simulink模型,对朗肯循环热功转化的核心部件单阀膨胀机进行了热力循环过程分析。分析了结构参数(膨胀机的缸径、行程和相对余隙容积系数)、运行参数(进气压力、进气温度和转速)、以及配气相位(进气阀升程和排气口宽度和高度)对膨胀机的输出功率、膨胀机效率、质量流量的影响规律。搭建了朗肯循环余热回收实验系统,确定了实验的控制策略。完成了实验系统性能测试实验,实验表明:在汽油机不同工况下,膨胀机转速为1352r/min—1978r/min,输出功率为2.06k W—3.47k W。当汽油机在转速为5500r/min,功率为76.6k W的稳定工况下,膨胀机的最高压力可以达到6.69MPa,膨胀机的指示功率可以达到5.06k W。朗肯循环的总效率在10%以上,使汽油机功率提高率最大达到5.8%。利用单阀膨胀机的升功率概念,从单位气缸容积做功能力的角度,对膨胀机做出评价。单阀膨胀机的升功率达到35.3k W/L,满足系统小型化的要求,具有良好的工程应用前景。理论分析与实验结果表明单阀膨胀机由于体积小、结构简单,适合小流量、小功率的场合,可以应用到发动机余热回收朗肯循环系统。
[Abstract]:The engine tail gas energy accounts for about 35% of the total amount of fuel burning and exothermic. Using the Rankine cycle system to recover the energy of exhaust gas is an effective way to save energy of the engine. In this paper, a theoretical and experimental study is carried out on the exhaust heat recovery system of gasoline engine tail gas based on the Rankine cycle. A gasoline engine model is established by using GT-Power, and the energy of exhaust gas is divided. The utilization potential of cloth and waste heat is analyzed. The study shows that the heat from the tail gas is equal to the output power of the gasoline engine, the maximum utilization rate of the tail gas is above 46%, and it has a great recovery potential. The effect of the back pressure on the power of the gasoline engine is simulated by using the gasoline engine model, which means the design of the guide Rankine cycle system. As well as the miniaturization of the equipment, water is selected as the Rankine cycle working substance and the performance index of the system is determined. A single valve expander Matlab/Simulink model is established. The thermodynamic cycle process is analyzed for the single valve expander, the core component of the transformation of the Rankine cycle, and the structure parameters (the cylinder diameter, stroke and phase of the expander) are analyzed. For the clearance volume coefficient), the operating parameters (intake pressure, intake temperature and speed), and the effect of the gas phase (intake valve lift and outlet width and height) on the output power of the expander, the efficiency of the expander and the mass flow. A Rankine cycle waste heat recovery experiment system was set up, and the experimental control strategy was determined. The experiment was completed. The experiment of system performance test shows that the expansion speed of the expander is 1352r/min 1978r/min and the output power is 2.06k W to 3.47k W. at different working conditions of the gasoline engine. When the gasoline engine is 5500r/min and the power is 76.6k W, the maximum pressure of the expander can reach 6.69MPa. The indicator power of the expander can reach the 5.06k W. Lang. The total efficiency of the Ken cycle is above 10%, which makes the increase of the power of the gasoline engine maximum to reach the concept of 5.8%. using the lift power of the single valve expander. From the angle of the capacity of the unit cylinder volume, the expander is evaluated. The rise power of the single valve expander reaches 35.3k W/L, which meets the requirements of the miniaturization of the system, and has a good prospect of engineering application. The analysis and experimental results show that the single valve expander can be applied to the engine waste heat recovery Rankine cycle system because of its small volume, simple structure, suitable for small flow and small power.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK115;TK411

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