Inversing Design On Performance And Turbocharging System Of A Long-stroke Sequential Turbocharging Diesel Engine

The inversing design of long-stroke sequential turbocharging (STC) diesel engine is discussed in this paper. Based on the software GT-POWER, a calculating model is set up. The mathematic model of the work processes in the cylinder is set up by zero-dimension model. And the air-flow in the inlet and exhaust pipe model is set up by one-dimensional unsteady flow model. And the mathematic model of turbocharging is set up by the equilibrium condition of the turbocharger.The STC system which has either 1TC or 2TC has been calculated and analyzed also, the calculated result tends to be in agreement with the experimental ones. It proved that the calculation model, method and the selection of the relative parameter are reasonable and the result could predict the performance of the diesel well. The performance of this diesel is discussed further based on the model above and is compared with the original diesel. In the circle of the work processes of the diesel, whether the gas exchanging processes is consummated is an important factor to the performance of the diesel. The gas fluctuation rule in the gas exchanging system is analyzed, and the influence of the work processes from it has been known.To avoid the surging problem, the working area is extened and the work processes using bypass pipe of the intake and exhaust system is simulated. After comparing with the experimental data and analyzing the performance and the running process of the diesel, the switch point and the bypass area are confirmed.Using the software Pro/E to set up the 3-D model of the inlet pipe of the diesel and the exhaust connect pipe of the two turbocharger, and using the software GAMBIT to carve up the mesh of the gridding, the flow field of the turbocharging system is calculated and analyzed in the rated operating condition by the software FLUENT. A new MPC exhaust pipe is designed in this thesis and is compared with the original one. The result of the exhaust pipe and the exhaust connect pipe is a good reference to the design, amelioration and optimum of the turbocharging system.