Explosion-proof Diesel Engine Inlet And Exhaust System Research

Explosion-proof diesel as the power source of the underground auxiliary transportation is welcome due to its performance, flexibility, high thermal efficiency, low fuel consumption and the other advantages. However,combustible gas produced by coal makes coal mine to become an explosive atmosphere. As the vehicle power source of emission temperature of the diesel engine can be as high as 650 ?, so the diesel engine must be reformed. In general, the installation of explosion-proof components on the ordinary diesel engine to become explosion-proof diesel engine. The explosion-proof elements including intake explosion-proof fence, exhaust explosion-proof fence, waste water tank, exhaust pipe and exhaust manifold using with water jacket double tube, exhaust temperature of less than 70 ?, body temperature lower than150?. However, equipped with explosion-proof components will make diesel engine power, fuel economy and power will decline, while emissions will deteriorate. Therefore, it is very important to study the internal gas flow and heat transfer of the explosion-proof components to improve the performance of the explosion-proof diesel engine.In thesis, with a certain type of explosion-proof diesel engine as the research object, using computational fluid dynamics(CFD) technology and the analysis software FLUENT to analyze the flow characteristics of the diesel engine air inlet explosion-proof barrier, the intake manifold, the water jacket exhaust pipe and the exhaust explosion-proof barrier, and provide a basis for future-proof diesel engine intake and exhaust system of research and design,structural improvements and other work. The main contents and conclusions of this study are as follows1. The structure of explosion proof diesel engine intake and exhaust system, function of main components and fire resistance mechanism are described in detail. The measures to improve the performance of the engine are listed.2. By using the three-dimensional modeling software Pro/E, the air intake explosion-proof barrier was established, and the influence of the length and diameter of the flow guide cover on the intake system was analyzed in FLUENT software. The results show that with the increase of the length of the shroud, the gas pressure and flow rate in the flow dome become more uniform,the recirculation zone and the velocity of the lower side of the flow guide cover are decreased. With the increase of the diameter of the shroud and decrease of the velocity pressure distribution in the shroud, the velocity distribution in the fence gap becomes uneven, the speed of the upper and the lower sides become smaller, and the utilization rate of the fence is reduced.3. Using FLUENT software to simulate the flow field in the intake manifold. It is found that the symmetry of the structure makes the pressure and velocity of the flow field close to the symmetric distribution. Due to the pressure loss along the path and the wall friction, the manifold pressure loss from the intake manifold is larger than that of the manifold pressure loss which close to the intake manifold.4. The establishment of the exhaust pipe with a water jacket using 3D modeling software Pro/E and imported into FLUENT. By using the flow solid coupling method, and analysis its internal high temperature flue gas flow and cooling water flow state, the results accord with the MT990-2006 of mine explosion proof diesel engine general technical conditions "requirements of the body surface temperature not higher than 150?.5. Using 3D modeling software Pro/E to draw three-dimensional model of exhaust explosion-proof fence, the gas velocity and pressure distribution in the exhaust gas explosion barrier are analyzed in FLUENT, and the flow property of the gas velocity and pressure distribution is analyzed without considering the temperature change. The results show that the air pressure of the upper part of the exhaust explosion-proof fence is larger, the lower part of the air pressure is smaller, this is because the lower part is close to the exhaust pipe, and the gas flow is more smooth.