Three-dimensional Numerical Simulation Study On Spiral Intake Ports Of TY3100 Non-road Diesel Engine

Energy and environmental protection have become two main themes of the contemporary world. As society and economy developing, the problem caused by non-road diesel engine emission has been widely drawing people's attention, and lots of countries have established non-road diesel engine emission regulation. For small non-road diesel engines, optimized matching among the fuel injection, in-cylinder air movement and the combustion chamber is an important means to reduce exhaust emissions. The air quantity entering the cylinders of a diesel engine and its swirl intensity has an important influence on the power output, economical performance and emissions of the engine. Simulation and analysis for the flow characteristics in intake ports based on Computational Fluid Dynamics (CFD) method can provide references to intake system optimization.In this thesis, the steady flow characteristics of the spiral intake port of TY3100 diesel engine were tested on the port steady flow test rig, and the intake port flow performance and influence of pressure difference on steady flow test were analyzed. The results show that the swirl ratio and flow coefficient of spiral intake port will increase with the increasing of valve lift, but the increasing trend gradually slowed down. Under the same valve lift, the flow coefficient does not change with the pressure differences, and the swirl ratio will increase with the pressure difference increases in the undeveloped turbulence areas, but will not vary in the full developed turbulence areas.Secondly, a numerical calculation on three-dimensional steady flow of the TY3100 engine spiral intake port was carried on by using STAR-CD software. The three-dimensional spiral inlet model was established through reverse engineering. The boundary conditions were taken from the port steady flow test. The calculation results have good agreement with the test results. According to the simulation results, an improvement scheme to the spiral intake port has been put forward, and then a simulation test for it has been done.At the same time, numerical simulations were performed to the intake port steady flow under turbocharged conditions. The steady flow characteristics of the intake port were compared between the results turbocharged conditions and naturally inspiration conditions. The calculation method on theoretical flow rate in the case of charged condition was put forward.In addition, the intake ports design method was investigated when four valves were used in the TY3100 diesel engine. An intake-port layout scheme was put forward and flow simulations were performed with the STAR-CD software. The results can provide references for further improvements to the diesel engine.