The Study On Exhaust System Of Big-Small-Turbine Sequential Turbocharged Diesel

Exhaust system not only affects the exhaust emission, but also have a major impact on Waste gas energy using,charge replacement,Pump gas losses and Diesel performance for the sequential turbocharged diesel. Reasonable choice and correct design of the diesel engine exhaust system is an important part of diesel engine system design. Big-Small--Turbine sequential turbocharged technology has a good effect on solving the diesel engine low load problem, so reasonable selection and design exhaust system are very important for the supercharged diesel engine which use this technology. therefore, the study on exhaust system of TBD234V12 Big-Small-Turbine sequential turbocharged diesel in this paper is of great significance.This article established the calculating model of TBD234V12 Big-Small-Turbine sequential turbocharged diesel. Cylinder used zero-dimensional model, taking into account the combustion characteristics of high-speed machine, and three-Weber curve has been used to simulate the heat release regulation; For intake and exhaust system, one-dimensional unsteady flow model was used, and used finite volume method to discrete partial differential equations. Based on the calculating model, the simulation models of the constant pressure, pulse and MPC three kinds of turbocharged system diesel engine were established using GT-POWER.The constant pressure, pulse and MPC three kinds of exhaust systems were designed for sequential turbocharged diesel; Based on the established simulation model, performance calculations were made for kinds of design projects of exhaust pipe and connecting pipe, and according to the calculated results determined the structure parameters of exhaust pipe.According to standard propeller characteristic, the three kinds of turbocharged system has been calculated using GT-POWER simulation models, and the impacts of the three kinds of exhaust system On performance parameters such as effective fuel consumption rate, the front row turbine temperature and pressure supercharger pressure, the biggest outbreak of pressure were studied. Finally, in accordance with calculation results, pulse turbocharged system was elected for the exhaust System of TBD234V12 Big-Small-Turbine sequential turbocharged diesel.In order to study the impact of exhaust pipe structure on the exhaust gas flow, and look for ways to reduce the flow losses, improve exhaust energy transfer efficiency , the three-dimensional flow of exhaust system was calculated by using Fluent software, and analyzed its three-dimensional flow characteristics. The results clearly showed that the structure of the exhaust pipe structure impacts on the flow field, and it provided a basis for the exhaust system design and optimization, and laid a foundation for further study.In addition, according to standard propeller characteristic, the strengthened TBD234V12 Big-Small-Turbine sequential turbocharged diesel of three kinds of turbocharged system have been calculated in this paper, and the characteristics of the three exhaust system were also analyzed, and provided a reference for the choice of High-pressure supercharger diesel's exhaust system.