Numerical Simulation And Performance Optimization Of COG Engine Work Process

Coke oven gas (COG) is one of the by-products in coking industry. As the biggest coal producing country, China produces massive COG with low utilization ratio. The treatments such as direct discharging and sky burning lead to great resource waste and air pollution. Theoretically, as the main components in COG, hydrogen and methane can be used as clean alternative fuel in internal combustion engine. But the variety of impurities and uncertain component proportion become the barrier of the application of COG to the internal combustion engine, especially to the vehicle engine. The work is a part of Gui Zhou Major Scientific and Technological Special Project-Research and Demonstrating Application of the Key Technology of COG-based Vehicle. Based on the simulation of COG combusting process in vehicle engine, a theoretical support is established for the application of COG to internal combustion engine.The combustion model provided by the traditional3D simulation software is no longer suitable because of the various components with different combustion characteristics in COG. With the method of sensibility analysis, this work provided a simplified mechanism of COG combustion in its components and reactions after a thorough analysis on the kinetic mechanism of the chemical reaction in the combustion process of the components in COG. The variables of the simplified mechanism are adjusted after comparing the laminar flame speed and ignition delay period between the simplified and detailed mechanism. The accuracy of the simulation is verified by comparing simulation results of the simplified and detailed mechanism. The1D and3D mathematical models of working process of the COG-based engine are created in GT-Power and AVL FIRE correspondingly. The simplified chemical reaction mechanism is coupled in3D model. The test results from the engine test bench validate the accuracy of the mathematical model established in this work.At last, based on the mathematical model created in this work, the simulation for the process and characteristics of COG combustion in internal combustion engine is made for further analysis on the influences of the compression ratio and ignition power on engine working process. The results indicate the COG-based internal combustion engine may have some loss of power. But it can be improved by increasing the compression ratio and ignition power.